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Applied Surface Science (v.259, #)

Investigation on the paraffin prevention performance of lanthanum-modified zinc powder by Zhiwei Wang; Liqun Zhu; Huicong Liu; Weiping Li (pp. 1-6).

► Lanthanum compound deposits on zinc powder by immersion La(NO₃)₃ solution. ► Paraffin prevention performance is evaluated by capillary rise experiment. ► Modified zinc powder has good paraffin prevention performance.Paraffin deposition in the oil pipeline is a serious problem during oil production. The zinc-rich coating can be a good candidate for paraffin prevention. In this paper, zinc powder used for the zinc-rich coating was modified with rare earth lanthanum to improve the paraffin prevention performance. Wetting behaviors (the relative contact angle and the saturation rate for paraffin on zinc powder) of bare and modified powder zinc were studied by capillary rise experiment to evaluate the paraffin prevention performance. The results indicated that the modification changed the surface morphology and composition of zinc powder, and modified zinc powder showed the best paraffin prevention performance (contact angle and saturation rate were 55° and 87.4%, respectively) after modification in the solution of 0.012mol/L La(NO₃)₃ for 24h.

Keywords: Zinc powder; Paraffin prevention; Lanthanum modification; Wetting behavior

Photoreactive mesoporous carbon/Bi₂WO₆ composites: Synthesis and reactivity by Su-Hua Chen; Zhen Yin; Sheng-Lian Luo; Xue-Jun Li; Li-Xia Yang; Fang Deng (pp. 7-12).

Display Omitted► We described the preparation and characterization of the mesoprous carbon/Bi₂WO₆ composites. ► The photocatalytic activities of the composites were also investigated. ► With the combination of photocatalysts and mesoporous carbon, increased separation efficiency of photoinduced electron–hole pairs and larger specific surface areas can be achieved. ► And to our knowledge, this is the first report concerning Bi₂WO₆ nanoparticles loaded on a mesoprous carbon.In order to develop highly efficient visible-light induced photocatalysts, Bi₂WO₆ powders and mesoporous carbon (MC)-modified Bi₂WO₆ (MC/Bi₂WO₆) photocatalysts were synthesized via a simple hydrothermal process in this paper. The samples of Bi₂WO₆ and MC/Bi₂WO₆ were characterized by X-ray diffraction (XRD), UV–visible spectroscopy, scanning electron microscopy (SEM) and BET surface area analysis, and their photocatalytic activity were evaluated by photocatalytic decoloration of rhodamine B (RhB) aqueous solution under visible light. It was found that the presence of MC could significantly improve the crystallization of Bi₂WO₆ species and photoabsorption property of Bi₂WO₆ in the visible region. The results also showed that the BET surface areas of MC/Bi₂WO₆ composites were larger than that of the pure Bi₂WO₆ and the photocatalytic activity of the MC/Bi₂WO₆ is much higher than that of Bi₂WO₆ with the optimum effect occurring at R_MC=0.10 (the weight ratio of MC to Bi₂WO₆). Close investigation revealed that the surface area, grain size and charge transfer of the as-prepared MC/Bi₂WO₆ composites could improve the photocatalytic activities.

Keywords: Mesoporous carbon; Bi; ₂; WO; ₆; Photocatalysis; Visible light

The numerical analysis of the spherical carbon adsorbents obtained from ion-exchange resins in one-step steam pyrolysis by M. Kwiatkowski; M. Wiśniewski; G. Rychlicki (pp. 13-20).

Display Omitted► The numerical analysis of spherical carbon adsorbents produced by the single-step steam pyrolysis have been presented. ► The porous structure was easily controlled by varying such factors as the carbonization temperature, atmosphere or the heating rate. ► The computer calculations using the LBET class models with the fast multivariant identification procedure were carried out. ► The research results will provide interesting information for the specialists engaged in porous structure description.This paper presents the numerical analysis of spherical carbon adsorbents produced by the single-step steam pyrolysis of a polystyrene-divinylbenzene resin. The porous structure of the materials produced this way was easily controlled by varying such factors as the carbonization temperature, atmosphere or the heating rate, allowing carbonaceous materials to have a controlled microporous structure. Due to their unique properties, the obtained adsorbents can be considered applicable in various processes in technology and environmental protection. The fast multivariant fitting procedure with the new adsorption numerical models of the LBET class was used for the analysis of the microporous structure. The computer calculations using the LBET class models with the fast multivariant identification procedure were carried out with the application of the nitrogen (77.15K) adsorption isotherms.

Keywords: Adsorbents; Micropores; Isotherms; Pyrolysis; Numerical analysis

Facile thermal explosion synthesis and optical properties of Al-doped flatted 3C-SiC microcrystals with 4H-SiC quantum interlayers by Yong Li; Jiangtao Li; Changxin Chen; Zengchao Yang; Yun Yang; Zhiming Lin (pp. 21-28).

► High-quality Al-doped flatted 3C-SiC microcrystals were in situ synthesized by a facile thermal explosion synthesis (TES) method. ► Structural and optical analysis reveals that one dimensional (1D) disordered regions, which structurally resemble wide band-gap 4H-SiC nano-interlays, are acquired and sandwiched in the 3C-SiC microcrystal matrix via Al doping. ► A new intensive, sharp ultraviolet (UV) photoluminescence is observed from the Al-doped flatted 3C-SiC microcrystals and the emission mechanism is discussed in terms of spontaneous polarization at the stacking faults.A facile thermal explosion synthesis (TES) method is developed to in situ synthesize batches of high-quality Al-doped flatted 3C-SiC microcrystals. Structural and optical analysis reveals that one dimensional (1D) disordered regions, which structurally resemble wide band-gap 4H-SiC nano-interlays, are acquired and sandwiched in the 3C-SiC microcrystal matrix via Al doping. High-resolution transmission electron microscopy (HRTEM) studies demonstrate that both atomic arrangements with growth predominantly in the 〈111〉 direction and planar structural defects coexist in the Al-doped flatted 3C-SiC microcrystals. A stacking sequence model is adopted to explain the formation mechanism of 4H-SiC nano-interlayers induced via Al doping. The photoluminescence (PL) spectra analysis shows that a new intensive, sharp ultraviolet (UV) emission (3.5eV) was observed for the flatted 3C-SiC microcrystal, except for a blue emission (3.1eV) derived from the surface defects. It is speculated that the quantum confined effect induced by quantum barrier structures is responsible for the new sharp UV emission. This comprises the first report of using a TES method for the synthesis of flatted Al-doped SiC microcrystals. The present method suggests a unique technique for synthesizing quantum barrier structures in SiC microcrystal matrix, which could be extended to other doping elements, and gives a new insight to understand the PL behavior of SiC materials.

Keywords: 3C-SiC; 4H-SiC; Al-doping; Optical properties; Quantum barrier structure

Effect of heterogeneous interface on the microwave dielectric properties of Ca(Mg_1/3Nb_2/3)O₃/CaTiO₃ thin films by Jing Zhou; Runrun Li; Ru Li; Wen Chen (pp. 29-33).

► Effect of heterogeneous interface on the microwave dielectric properties was studied. ► The CMN/CT films were uniform, smooth and dense. ► The CMN/CT films have single perovskite phase regardless of interface number. ► The depletion layers were formed between CMN and CT films. ► The dielectric properties of films were improved with adding heterogeneous interfaces.Effects of heterogeneous interface on the dielectric properties of Ca(Mg_1/3Nb_2/3)O₃/CaTiO₃ (CMN/CT) thin films fabricated by Pechini technique were investigated in this work. As-prepared CMN/CT thin films were uniform, smooth and dense with the thickness of around 190nm. AFM results showed that the root mean square (RMS) surface roughness of CMN/CT thin films decreased as the heterogeneous interface numbers increases and the NI-11 sample possesses minimal RMS. Compared with measured results, the calculated dielectric constant was slightly lower and with increasing heterogeneous interface numbers, the measured dielectric constant of the films increased gradually while the dielectric loss decreased. These results implied that heterogeneous interfaces were favorable for the improvement of dielectric properties, which was also attributed to the formation and accumulation of depletion layers at the CMN/CT interfaces that reduced lattice relaxation. Being indexed by XRD patterns and EDS spectrum, the inter-diffusion between the CMN and CT layer was further confirmed. Moreover, the CMN/CT thin films had single phase in their own layers independently regardless of interface number.

Keywords: CMN/CT; Heterogeneous interface; Thin film; Dielectric property

RHEED study of the growth of cerium oxide on Cu(111) by Karel Mašek; Jan Beran; Vladimír Matolín (pp. 34-38).

► Epitaxial (111) oriented CeO₂ layers were grown on Cu(111)) surface at different substrate temperatures. ► The CeO₂ layers grew by formation of flat islands. ► Morphology of CeO₂ layers was determined from RHEED profile analysis. ► The contraction of CeO₂ crystal lattice with respect to the bulk value was observed. ► XPS measurements have shown that the CeO₂ structure contained only Ce⁴⁺ oxidation state.This article reports RHEED and XPS studies of the growth of epitaxial cerium oxide layers on (111) surface of copper single-crystal. The layers were prepared by reactive evaporation of cerium in 5×10⁻⁵Pa of oxygen at different substrate temperatures. Cerium oxide layers exhibited (111) crystallographic plane parallel to the substrate surface. The model of CeO₂(111)/Cu(111) epitaxial system is proposed. Morphological parameters of cerium oxide layer were deduced from RHEED diffraction patterns. It was found that average island size increased with the substrate temperature during the deposition. The obtained results are in agreement with the similar studies performed by STM. An experimental arrangement of the RHEED technique permitted to measure an evolution of lattice parameter of cerium oxide during the growth. A contraction of crystal lattice was observed especially in early stages of the growth. XPS measurements indicated the growth of stoichiometric cerium oxide.

Keywords: PACS; 61.05.jh; 68.47.GhCerium; Cerium oxide; Epitaxial growth; RHEED; XPS; Lattice parameter

Chemical synthesis of spinel cobalt ferrite (CoFe₂O₄) nano-flakes for supercapacitor application by V.S. Kumbhar; A.D. Jagadale; N.M. Shinde; C.D. Lokhande (pp. 39-43).

► The first time preparation of cobalt ferrite material in thin film form, using chemical method at low temperature. ► A nano-flake like morphology of the cobalt ferrite thin film. ► An application of the film as an electrode in supercapacitor cell.The present paper reveals the formation of cobalt ferrite (CoFe₂O₄) thin film on stainless steel substrate by simple chemical route from an alkaline bath containing Co²⁺ and Fe²⁺ ions. The films are characterised for structural, surface morphological and FT-IR properties. The XRD and FT-IR studies revealed formation of single phase of CoFe₂O₄. The formation of nano-flakes-like morphology is observed from scanning electron microscope. The electrochemical behaviour of CoFe₂O₄ film has been studied using cyclic voltammetry in 1M NaOH electrolyte. The maximum specific capacitance of 366Fg⁻¹ is obtained at the scan rate of 5mVs⁻¹. Using AC impedance technique equivalent series resistance (ESR) value is found to be 1.1Ω.

Keywords: Ferrite; Chemical route; Nano-flakes; Supercapacitor

Arrays of nanostructured antidot in Ni₈₀Fe₂₀ magnetic thin films by photolithography of polystyrene nanospheres by Paola Tiberto; Luca Boarino; Federica Celegato; Gabriele Barrera; Natascia De Leo; Marco Coisson; Franco Vinai; Paolo Allia (pp. 44-48).

► Arrays of antidot in Ni₈₀Fe₂₀ thin films by photolithography of polystyrene nanospheres. ► Well-ordered Antidot arrays on a large scale. ► Novel method exploiting optical lithography with enhanced spatial resolution. ► We report on the presence of an anisotropic magnetoresistance signal.Ordered nanostructures consisting in arrays of nanopores and nanoholes in magnetic thin films have been the subject of intensive research. In this work, a novel multi-step lithography process based on self-assembling of polystyrene nanospheres is proposed to pattern arrays of nanoholes on a Ni₈₀Fe₂₀ thin film. Such a method allows antidot patterns to be fabricated on a wider area with respect to the standard sequential lithography. A polymeric mask is created by depositing a layer of polystyrene nanospheres on a photoresist subsequently exposed to a mercury lamp. The novelty in the procedure lies in exploiting low-cost and fast, non-sequential optical lithography with enhanced spatial resolution. Arrays of holes having mean size ranging in the interval of 250–280nm depending on the experimental conditions have been prepared in Ni₈₀Fe₂₀ films of different thickness (between 20 and 60nm). Sample morphology has been checked by scanning electron microscopy. Magnetic and magnetotransport properties have been measured as a function of temperature on films of different thickness. An anisotropic magnetoresistance effect has been observed in all patterned films independent on the film thickness. This result, similar to the ones reported for patterned nanostructure obtained with conventional lithography techniques, confirms the potential of the proposed technique.

Keywords: Self-assembling; Polystyrene; Nanospheres; Nanomagnetism

Raman and NMR studies of aged LiFePO₄ cathode by Shrikant C. Nagpure; Bharat Bhushan; S.S. Babu (pp. 49-54).

► Raman spectroscopy used to characterize the quality of carbon coating in LiFePO₄ commercial cells aged with C-rate. ► Structural change in the carbon coating leading to low electrical conductivity is observed for the cells aged at higher C-rate. ► Nuclear magnetic spectroscopy used to characterize LiFePO₄ nanoparticles for the presence of Li. ►⁷Li peak is observed in an unaged cell, while the similar peak is absent in the aged cells.The carbon coated LiFePO₄ nanoparticles are used in advanced lithium-ion batteries due to low cost, high energy and power density. In this paper Raman spectroscopy is used to analyze the degradation of carbon coating around these nanoparticles in several commercial cells aged with different C-rate. Magic angle spinning⁷Li Nuclear magnetic resonance (NMR) spectroscopy is used to characterize these nanoparticles for the presence of Li. In Raman spectroscopy data, structural change in the carbon leading to low electrical conductivity is observed for the cells aged at higher C-rate. In NMR spectroscopy data, isotropic⁷Li peak is observed in an unaged cell, while the similar peak is absent in the aged cells.

Keywords: Lithium-ion batteries; Aging; Carbon-coating; Raman spectroscopy (RS); Magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy

Sorbitol as an efficient reducing agent for laser-induced copper deposition by V.A. Kochemirovsky; L.S. Logunov; S.V. Safonov; I.I. Tumkin; Yu. S. Tver’yanovich; L.G. Menchikov (pp. 55-58).

Display Omitted► Copper lines were deposited on the surface of ceramics using sorbitol. ► Sorbitol as a reductant leads to deposition of conductive copper lines. ► Topology of deposits was studied by SEM and scanning probe microscopy. ► Elemental composition of deposited lines was studied by EDX analysis. ► Electrical properties of copper were examined by impedance spectroscopy.We have pioneered in revealing the fact that sorbitol may be used as an efficient reducing agent in the process of laser-induced copper deposition from solutions; in this case, it is possible to obtain copper lines much higher quality than by using conventional formalin.

Keywords: Sorbitol; Reducing agent; LCLD; Laser-induced deposition; Solution; Copper; Topology

c-axis orientation and piezoelectric coefficients of AlN thin films sputter-deposited on titanium bottom electrodes by A. Ababneh; M. Alsumady; H. Seidel; T. Manzaneque; J. Hernando-García; J.L. Sánchez-Rojas; A. Bittner; U. Schmid (pp. 59-65).

► The surface roughness of the titanium bottom electrode (Ti) is a dominating factor on the piezoelectric coefficients and structure of AlN thin films. ► Increasing the surface roughness of Ti bottom electrode results in open-porous surface characteristics and low piezoelectric coefficients of the AlN top layer. ► Decreasing the surface roughness of Ti bottom electrode results in a smooth and dense surface which is a necessary requirement for high piezoelectric coefficients. ► Both piezoelectric coefficients d₃₃ and d₃₁ were determined by comparing the experimental and simulated displacement profile of the piezoelectric film.Aluminum nitride (AlN) reactively sputter deposited from an aluminum target is an interesting compound material due to its CMOS compatible fabrication process and its piezoelectric properties. To obtain high piezoelectric coefficients it is a necessary pre-request to synthesize films with c-axis orientation. Besides the influence of sputter conditions on the microstructure of AlN thin films the condition of the substrate surface is another important factor of utmost importance. In this study, the influence of 350nm thick titanium metallization DC sputter-deposited on SiO₂/Si substrates at varying back pressure levels b_p,Ti in the range of 2×10⁻³ to 14×10⁻³mbar on the c-axis orientation and the piezoelectric coefficients of 600nm thick AlN thin films is investigated. Besides the plasma power for Ti deposition ( P_p,Ti=100W) the parameters for AlN synthetization are fixed to P_p=1000W and b_p,AlN=4×10⁻³mbar in 100% N₂ atmosphere. Basically, the surface roughness of the Ti bottom layer is the dominating factor resulting either in a high degree of c-axis orientation (i.e. at low b_p,Ti values) or in an amorphous AlN microstructure (i.e. at high b_p,Ti values). Under low pressure conditions, a smooth and dense surface characteristics is achieved due to a higher kinetic energy associated with the adatoms what is especially important at nominally unheated substrate conditions. The piezoelectric coefficient d₃₃ decreases from 2.55 to 1.7pm⁻¹ when increasing the titanium sputter pressure from 2×10⁻³ to 14×10⁻³mbar. When decreasing the Ti film thickness to 60nm and hence, reducing the root mean square roughness by a factor of about 2, the intensity associated with the AlN (002) peak is increased by a factor of about 1.7 demonstrating the direct impact. Furthermore, the highest values for d₃₃ and d₃₁ (i.e. 3.15pmV⁻¹ and −1.28pmV⁻¹) are determined.

Keywords: Aluminum nitride; Metal electrode; Thin film; Sputter deposition technique; XRD analyses; c; -axis orientation; Surface roughness; Piezoelectric coefficients; Laser vibrometry

Research on the effects of machining-induced subsurface damages on mono-crystalline silicon via molecular dynamics simulation by Hongwei Zhao; Chengli Shi; Peng Zhang; Lin Zhang; Hu Huang; Jiwang Yan (pp. 66-71).

► MD simulations of nano-cutting process are carried out to obtain machining-induced subsurface with diamond cutting tools. ► After cutting, the crystal lattice reconstructed and led to the formation of the machined surface. ► The mechanical properties of the pristine and machining-induced subsurface Si are studied by means of nanoindentation. ► Nanoindentation results show that the hardness of the machined surface was smaller than mono-crystalline Si.Nanoindentation simulation via molecular dynamic (MD) method was carried out to investigate the characteristics of machining-induced subsurface damage of mono-crystalline silicon with a spherical diamond indenter. In this study, MD simulations of nano-cutting process were carried out firstly to cut through the specimen's surface with diamond cutting tools of different edge radius of 0nm, 3nm and 5nm respectively. Then, MD simulation of nanoindentation on the machined surface was carried out. Tersoff potential was used to model the interaction of Si atoms, and the interaction between Si and C atoms was modeled by Morse potential. Simulational results indicate that during cutting process, the specimen undergo plastic deformation and phase transformation. After cutting process, the crystal lattice reconstructs and the residual amorphous layers lead to the formation of the machined surface. Nanoindentation results show that the hardness of the machined surface is smaller than mono-crystalline Si. So in order to get accurate properties of the pristine silicon or other semiconductor materials via experiments, the amorphous phase should be completely removed or it would influence the mechanical properties of the pristine materials.

Keywords: Molecular dynamics; Nano-cutting; Nanoindentation; Machining-induced phase transform; Silicon

Effect of n-HA with different surface-modified on the properties of n-HA/PLGA composite by Jiang Liuyun; Xiong Chengdong; Chen Dongliang; Jiang Lixin; Pang xiubing (pp. 72-78).

The bend strength of n-HA/PLGA composite with the unmodified n-HA becomes lower than that of PLGA. However, when n-HA was modified by different methods, the bend strength of g-n-HA/PLGA composites gets a little increase than PLGA, and the g3-n-HA/PLGA shows the highest bend strength at 3% g3-n-HA loading amount in weight, reached 162MPa, which was 24.4% higher than that of pure PLGA.Display Omitted► A new surface modification method for n-HA of combining stearic acid with surface-graftingl-lactic was adopted. ► Three different surface modification methods for n-HA were compared in detail. ► The new surface modification method was the most ideal method in this study. ► The g3-n-HA/PLGA composite had the highest bending strength, which would be potential to be used as bone fracture internal fixation materials.Three different surface modification methods for nano-hydroxyapatite (n-HA) of stearic acid, grafted withl-lactide, combining stearic acid and surface-graftingl-lactic were adopted, respectively. The surface modification reaction and the effect of different methods were evaluated by Fourier transformation infrared (FTIR), X-ray photoelectron spectra (XPS), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM). The results showed that n-HA surfaces were all successful modified, and the modification method of combining stearic acid and surface-graftingl-lactic had the greatest grafting amount and the best dispersion among the three modification methods. Then, the n-HA with three different surface modification and unmodified n-HA were introduced into PLGA, respectively, and a serials of n-HA/PLGA composites with 3% n-HA amount in weight were prepared by solution mixing, and the properties of n-HA/PLGA composites were also investigated by electromechanical universal tester and scanning electron microscope(SEM), comparing with PLGA. The results showed that the n-HA/PLGA composite with the n-HA surface modified by combining stearic acid and surface-graftingl-lactic had the highest bending strength and the best dispersion and interfacial adhesion among the three different modification methods, suggesting the surface modification of combining stearic acid and surface-graftingl-lactic was the most ideal method in this study, which has a great deal of enhancement of bending strength than PLGA, and it would be potential to be used in the field of bone fracture internal fixation in future.

Keywords: Poly-lactic-co-glycolic acid; Nano-hydroxyapatite; Surface modification

Synthesis and field emission of β-SiC nanowires on silicon nanoporous pillar array by Haiyan Wang; Zijiong Li; Liping Kang; Xinjian Li (pp. 79-82).

► β-SiC nanowires were grown on silicon nanoporous pillar array by a CVD method. ► Low turn-on field and high enhancement factor were obtained in nw-SiC/Si-NPA. ► Enhanced field-emission was due to the hierarchy structure of nw-SiC/Si-NPA.Nonaligned β-SiC nanowires ( nw-SiC) were grown on silicon nanoporous pillar array (Si-NPA) by a chemical vapor deposition (CVD) method with nickel as the catalyst. The curly hair like SiC nanowires and the silicon pillar array formed a nanometer-micron hierarchy structure. The field-emission measurements to nw-SiC/Si-NPA showed that a lower turn-on field of 2.9Vμm⁻¹ was obtained, and the enhancement factor of nw-SiC/Si-NPA according to the Fowler–Nordheim (F–N) theory reached 5200. The excellent field-emission performance was attributed to the nanometer-micron hierarchy structure of nw-SiC/Si-NPA, including the high aspect ratio of the SiC nanowires and the regular surface undulation of Si-NPA which increased the emission sites density and might have reduced the electrostatic shielding among the emitters.

Keywords: Silicon carbide nanowires; Silicon nanoporous pillar array; Field emission

Mechanism analysis of improved DLC films friction behaviors with liquid sulfidation treatment by Qunfeng Zeng; Fei Yu; Guangneng Dong; Junhong Mao (pp. 83-92).

► Liquid sulfidation is applied to treat DLC films. ► Sulfur atoms are chemically bonded and the graphitization presented in the treated films. ► The treated films exhibited much lower coefficient of friction than the untreated films under dry friction condition. ► The sulfidation mechanisms are supposed as surface chemical reaction and surface diffusion. ► The presence of sulfur-containing materials and graphitization are beneficial to improve anti-friction behaviors of the treated films.Diamond like carbon (DLC) films were treated by liquid sulfidation to improve their friction behaviors. Friction behaviors of DLC films were experimentally evaluated in ambient air under dry friction using GCr15 steel ball sliding over DLC-coated steel flat in a ball-on-disk tribometer system. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were applied to identify the chemical composition and structure of DLC films. It was found that the content of sp² carbon bond increased and G peak shifted to high wave number after sulfidation treatment. The measurement results showed that sulfur atoms were chemically bonded and the graphitization occurred in the treated DLC films. It was indicated that the treated DLC films exhibited much better friction behaviors than the untreated films, especially for DLC films deposited with high nitrogen ratio. In this paper, we proposed the possible sulfidation mechanism of sulfurized DLC films. Sulfidation mechanism is postulated that thiourea reacted with oxygen to form sulfur-containing organic compounds which included CSSC, CSOH and (NH₂)NHCSO₂H and surface diffusion during sulfidation treatment. The anti-friction behaviors of the treated DLC films can be attributed to the production of the compounds containing sulfur on the DLC film surface, the reduce of oxygen content and the presence of graphitization of DLC films.

Keywords: Diamond like carbon films; Liquid sulfidation; Structure; Mechanism; Anti-friction behaviors

Surface properties of bionic micro-pillar arrays with various shapes of tips by Dapeng Wang; Aiwu Zhao; Rui Jiang; Da Li; Maofeng Zhang; Zibao Gan; Wenyu Tao; Hongyan Guo; Tao Mei (pp. 93-98).

► A facile strategy was reported to fabricate gecko-inspired micro-pillar arrays. ► The spatular, spherical and concave tips were obtained. ► Spatular tips are helpful for adhesion enhancement of micro-pillar arrays. ► The shape of tip controls the contact angles of water droplets on the interface.Gecko-inspired micro-pillar arrays with various tip structures including spatular, spherical and concave tips were fabricated by a facile soft-molding method. The tip structures of micro-pillar arrays strongly depend on different curing processes in soft-molding using the same template. The adhesion and the wetting properties of these micro-pillar arrays are investigated by means of triboindenter and optical contact angle measurement. The results suggest that the surface properties are determined by different tip structures of micro-pillars. The spatular tip and concave tip are helpful for the adhesion enhancement and the shape of tip can control the contact angles and stabilities of water droplets on the micro-pillar arrays. In addition, the procedures demonstrate that the present route to fabricate gecko-inspired micro-pillar arrays with various tip structures is reliable and convenient. We believe that this research may pave the road to further understanding the gecko-inspired attachment systems and designing new artificial structures for dry adhesives.

Keywords: Gecko-inspired; Micro-pillar array; Tip structure; Adhesion; Wetting

Controllable electrochemical synthesis of ZnO nanorod arrays on flexible ITO/PET substrate and their structural and optical properties by Yeong Hwan Ko; Myung Sub Kim; Jae Su Yu (pp. 99-104).

Display Omitted► Vertically aligned ZnO nanorod arrays were grown on flexible transparent substrate by the electrodeposition. ► Morphology and optical properties were controlled by varying the deposition voltage and the concentration of growth solution. ► Crystallinity and photoluminescence were studied under different growth conditions. ► Well aligned ZnO nanorod arrays show the good antireflection and wetting properties. ► Optimized ZnO nanorod arrays exhibit an increased diffuse light scattering with keeping high transparency.The structural and optical properties of vertically aligned zinc oxide (ZnO) nanorod arrays (NRAs) which were grown on the flexible indium tin oxide (ITO) coated polyethylene terephthalate (PET) substrate (i.e., ITO/PET substrate) with a thin sputtered ZnO seed layer via the electrochemical deposition method were studied. By changing the applied voltage and zinc nitrate concentration, the height/width and density of ZnO NRAs were controlled, with investigation on their crystallinity and optical properties. To understand the effect of ZnO seed layer on the growth property of ZnO nanorods, they were also grown on ITO/PET without any seed layer. Under an applied cathodic voltage of −2V and zinc nitrate concentration of 10mM, the ZnO NRAs increased the total transmittance up to 88.7% in the visible wavelength region due to the antireflective property and their X-ray diffraction (002) peak intensity was largely enhanced. Additionally, the near band edge emission of ZnO was significantly enhanced in photoluminescence spectrum. The light scattering and surface wetting properties were also explored.

Keywords: PACS; 81.05.Dz; 82.45.Aa; 81.07.−b; 78.55.Et; 42.79.WcFlexible substrate; ZnO nanorod arrays; Electrochemical deposition; Antireflection; Photoluminescence; Crystallinity; Hydrophilicity

Inductively coupled plasma etching to fabricate sensing window for polymer waveguide biosensor application by Xibin Wang; Jie Meng; Xiaoqiang Sun; Tianfu Yang; Jian Sun; Changming Chen; Chuantao Zheng; Daming Zhang (pp. 105-109).

► We designed and fabricated an improved sensing window based on the ICP method. ► The sensitivity of the sensor was enhanced by a factor of 2.8 in theory. ► The etching rate of P(MMA–GMA) was twice as fast as that of SU-8 2005. ► The parameters were optimized to minimize the surface roughness in the etched area. ► The sensor presented a higher sensitivity than the conventional waveguide sensor.Integrated polymeric waveguide biosensors are usually used for the detection of chemical/biological samples. To improve the sensitivity of the conventional waveguide sensors with only one sensing surface, we design and fabricate an improved sensing window with three sensing surfaces based on inductively coupled plasma etching method, whose sensitivity can be enhanced by a factor of 2.8 in theory. The effects of etching parameters, especially the antenna power, the bias power and the O₂ flow rate were systematically studied and the parameters were optimized to fabricate the sensing window. A single-mode balanced Mach–Zehnder interferometer waveguide biosensor with the improved sensing window was fabricated under this optimum etching condition, and presented a higher sensitivity than that of the sensor with conventional sensing window. This type of sensing window will be very useful in polymer waveguide biosensor devices.

Keywords: Inductively coupled plasma etching; Polymer; Sensing window; Waveguide biosensor

Preparation of superhydrophobic and UV blocking cotton fabric via sol–gel method and self-assembly by Chengyu Pan; Li Shen; Songmin Shang; Yanjun Xing (pp. 110-117).

► Transparency and stability nano-Al sol was prepared with Al(NO₃)₃. ► Sample by Al sol and sodium stearate showed superhydrophobicity and UV protection. ► Hydrophobic treatment does not introduce new phases of Al coating.Superhydrophobic surface has been successfully prepared on cotton substrates with inexpensive and ordinary raw materials, Al(NO₃)₃ and sodium stearate (C₁₇H₃₅COONa). Such surfaces were obtained first by dip-coating the nano-Al sol, then the surface of the Al coating was modified with sodium stearate, to gain a thin film through self-assembly. The wettability of treated fabrics was characterized by water contact angle, spray test and hydrostatic pressure test. The results showed that the cotton fabrics treated with 1.5% Al sol and 20mmol/L sodium stearate showed excellent hydrophobic properties and UV protection efficiency, water contact angle could reach 146.27° and the UPF value was 164.06 (UPF rating 50+). The morphology and surface roughness were characterized by SEM and AFM. The interaction between sodium stearate and Al coating was elucidated by XPS.

Keywords: Superhydrophobicity; UV-blocking; Cotton; Sol–gel; Self-assemble

Enhanced photocatalytic H₂-production activity of Cd_xZn1−_xS nanocrystals by surface loading MS (M=Ni, Co, Cu) species by Jian Wang; Bo Li; Jiazang Chen; Na Li; Jianfeng Zheng; Jianghong Zhao; Zhenping Zhu (pp. 118-123).

► Cd_xZn1−_xS solid solution was prepared by co precipitation reflux method. ► MS (M=Ni, Co, Cu) provides active sites for Cd_xZn1−_xS hydrogen evolution. ► The hydrogen production rate of MS/Cd_0.4Zn_0.6S is 5 times higher than Cd_0.4Zn_0.6S. ► MS causes fast diffusion of photoelectrons generated from Cd_0.4Zn_0.6S toward MS.To investigate the role of metal sulfides as co-catalyst for photocatalytic hydrogen production under visible light irradiation, we have loaded small amounts of transition-metal sulfides (MS), such as NiS, CoS and CuS, onto the surface of Cd_xZn1−_xS solid solution. It can be found that the rate of H₂ evolution over the MS/Cd_0.4Zn_0.6S was 5 times higher than that of the pure Cd_0.4Zn_0.6S, and is comparable to the Cd_0.4Zn_0.6S modified with 1wt% platinum (Pt) co-catalysts. The MS/Cd_0.4Zn_0.6S photocatalysts were characterized by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), UV–visible spectrophotometer (UV–vis), and photoluminescence (PL) spectroscopy. It can be speculated that the MS provided active sites for H₂ production and caused the migration of excited electrons from Cd_0.4Zn_0.6S toward MS, leading to the enhancement of photocatalytic activity.

Keywords: Cd; _x; Zn; 1−; _x; S solid solution; Co-catalyst; Photocatalysis; Hydrogen production; Transition-metal sulfides

A statistical approach for the characterization of self-assembled hexagonal lattices by Mohammadreza Pourfard; Karim Faez (pp. 124-134).

► A simple fast method for defining the degree of ordering is proposed. ► This method uses the statistical characteristics of AAO structure. ► This method relies on some image and signal processing techniques. ► This method has no predetermined parameters. ► This method defines the dominant orientations.Different anodization conditions create different lattices of aluminum oxides. Some lattice characterization techniques have been proposed in the literature to quantify the effects of these conditions. In this paper, a statistical method for evaluating the degree of ordering in the hexagonal nano-porous anodized aluminum oxide (AAO) lattices has been proposed. A robust preprocessing technique is used to eliminate the irregularity of the background of the SEM image of these structures. Then the maximum variance of the summation of the intensity value of two directions of the image in different orientations is used to determine the degree of ordering. The mentioned variance signal also shows the dominant and other orientations of the nano pores in an AAO image. One new criterion is also introduced which could exactly characterize the whole lattice.

Keywords: Nanostructures; Quantitative grain analysis; Anodic alumina oxide characterization; Image processing; Signal processing

Changes in ionization potentials of MgO and CaO films upon heating in air and vacuum investigated by metastable de-excitation spectroscopy by K. Yoshino; Y. Morita; T. Nagatomi; M. Terauchi; T. Tsujita; Y. Doi; T. Nakayama; Y. Yamauchi; M. Nishitani; M. Kitagawa; Y. Yamauchi; Y. Takai (pp. 135-141).

► Chemisorption of H₂O and CO₂ markedly changes the ionization potential of CaO. ► Heating in vacuum is effective to cleaning the MgO surface but not effective for CaO. ► The firing voltage of plasma display panels and the ionization potential correlate. ► Metastable de-excitation spectroscopy is effective to evaluating protective layers.Changes in the ionization potential of MgO and CaO film surfaces upon heating in air and vacuum, which are necessary processes in the manufacture of plasma display panels, were investigated by metastable de-excitation spectroscopy. Heating at 500°C for 1min in vacuum is effective for cleaning an MgO film surface previously heated in air, resulting in the recovery of the ionization potential of the cleaned MgO surface from the increased value upon heating in air. A similar treatment is not effective for the CaO surface. This difference in behavior can be attributed to the stronger bonding states of H₂O and CO₂ on CaO than those on MgO. This is consistent with the fact that CaO has not yet been practically used as a protective layer in plasma display panels. Furthermore, the firing voltages of the plasma predicted for the MgO and CaO protective layers from the ionization potentials determined by metastable de-excitation spectroscopy were found to qualitatively agree with measured firing voltages obtained for a test panel. The present results confirmed that metastable de-excitation spectroscopy is effective for evaluating protective layers used in plasma display panels.

Keywords: Plasma display panel; Protective layer; Ion-induced secondary electron emission; Density of states; Metastable de-excitation spectroscopy; Ionization potentialPACS; 52.75.-d; 79.60.Dp; 73.20.At

Preparation and characterization of gradient wettability surface depending on controlling Cu(OH)₂ nanoribbon arrays growth on copper substrate by Ziheng Huang; Jiaoru Zhang; Jiang Cheng; Shouping Xu; Pihui Pi; Zhiqi Cai; Xiufang Wen; Zhuoru Yang (pp. 142-146).

► Gradient wettability surface with contact angle from 90.5° to 3.0° was prepared on copper substrate. ► The gradient wettability surface was obtained by controlling the growth condition of Cu(OH)₂ nanoribbon arrays. ► It was through varying immersing time of the substrate in aqueous solution of NaOH and (NH₄)₂S₂O₈. ► The gradient wetting property of the copper substrate was tested to be thermally stable and water resistant. ► CA, SEM, XRD, XPS were employed to characterize the gradient wettability surface.Gradient wettability surface was prepared on copper substrate via a facile alkali assistant surface oxidation technique. It was based on the control of cupric hydroxide (Cu(OH)₂) nanoribbon arrays growth from the upper part to lower part along the vertically placed copper substrate in an aqueous solution of NaOH and (NH₄)₂S₂O₈. Thus the gradient wettability functionalized Cu(OH)₂ nanoribbon arrays were directly fabricated on copper substrate by varying the immersing time of different positions along the substrate surface. By using a relative dilute NaOH solution (0.75mol/L) and (NH₄)₂S₂O₈ solution (0.03mol/L), and regulating dropping speed, the surface gradient wettability changing from the original contact angle of copper substrate (90.5°) to surperhydrophilicity (3.0°) was prepared. The surface fabricated on copper substrate may keep its gradient wetting property after immersed in water bath at 100°C for 10h. The water contact angle measurement (CA), Scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were employed to analyze the wettability, morphologies, crystal structure, and surface chemical compositions of the Cu(OH)₂ nanoribbon arrays on copper substrate. This research is expected to be significant in providing a new strategy for the preparation of novel gradient wettability material with potential industrial applications on copper substrate.

Keywords: Gradient wettability surface; Cu(OH); ₂; nanoribbon arrays; Alkali assistant surface oxidation technique; Contact angle

Enhanced tribology durability of a self-assembled monolayer of alkylphosphonic acid on a textured copper substrate by Yong Wan; Yinhu Wang; Quan Zhang; Zhongqian Wang; Zhen Xu; Changsong Liu; Junyan Zhang (pp. 147-152).

► A textured surface is prepared on the copper substrate by chemical etching. ► The alkylphosphonic acid is assembled on the etched copper substrate. ► Combining texturing and alkylphosphonic acid coating render the films hydrophobicity. ► The dual-layer films possess low friction with extremely long duration.A simple two-step process was developed to render the copper surface with lower friction and long durability. The copper substrate was immersed in a 0.01M NaOH solution to fabricate a textured Cu₂O film. A self-assembled monolayer of alkylphosphonic acid was then deposited on the Cu₂O film to acquire high hydrophobicity. Scanning electron microscopy, Fourier transform infrared microscopy and water contact angle measurements were used to analyze the morphological features, the chemical composition and hydrophobicity of freshly prepared samples, respectively. Moreover, the friction-reducing behavior of the organic-inorganic composite film sliding against steel was evaluated in a ball-on-plate configuration. It was found that the alkylphosphonic acid films on the textured Cu₂O film led to decreased friction with significantly extended life. For a constant load, the increase in chain length of alkylphosphonic acid yields the films that are dramatically more stable against tribological deformation and provide low coefficients of friction over much longer periods of time.

Keywords: Thin film; Friction; Self-assembled monolayer; Chemical etching; Copper

The effect of lizardite surface characteristics on pyrite flotation by Bo Feng; Qiming Feng; Yiping Lu (pp. 153-158).

► Two kinds of lizardite samples have different effect on the flotation of pyrite. ► Acid leaching changed the surface characteristics of lizardite mineral. ► The leached lizardite has less magnesium on its surface. ► The electro-kinetic behavior of lizardite aqueous suspensions is mainly a function of the Mg/Si atomic ratio on mineral surface.The effect of lizardite surface characteristics on pyrite flotation has been investigated through flotation tests, adsorption tests, zeta potential measurements, FTIR study, X-ray photoelectron spectroscopy (XPS) and sedimentation tests. The flotation results show that at pH value 9, where flotation of nickel sulfide ores is routinely performed, two kinds of lizardite samples (native lizardite and leached lizardite) have different effects on the flotation of pyrite. The native lizardite adheres to the surface of pyrite and reduces pyrite flotation recovery while the leached lizardite does not interfere with pyrite flotation. Infrared analyses and XPS tests illustrate that acid leaching changed the surface characteristics of lizardite mineral and the leached lizardite has less magnesium on its surface. It has been determined that the electro-kinetic behavior of lizardite aqueous suspensions is mainly a function of the Mg/Si atomic ratio on lizardite surface. So, the low isoelectric point observed in the leached sample has been linked to values of this ratio lower than that of the native lizardite.

Keywords: Lizardite; Surface characteristics; Magnesium ions; Flotation

Preparation of nanosensors based on organic functionalized MWCNT for H₂S detection by F. Mohammadzadeh; M. Jahanshahi; A.M. Rashidi (pp. 159-165).

► H₂S detection in natural gas (about 160ppm) at different operating temperatures (25–80°C) was investigated. ► MWCNT was obtained by enhanced CVD method over Co-Mo/MgO catalyst in reasonable operation conditions. ► Operating temperatures and type of additives greatly affect on gas sensors response time and recovery. ► Amides are good candidates in sensors to operate at room temperatures.The effects of various organic functional groups on electrical responses of multiwalled carbon nanotube sensors for H₂S detection in natural gas (about 160ppm) at different operating temperatures (25–80°C) were investigated. The experimental results showed that the amino groups functionalized carbon nanotube nanosensor displayed good chemical sensitivity (25–30%) at room temperature because ofNH reactive sites on the tubes while MWCNT group had excellent performances at higher temperatures. The mechanistic of optimum conditions for functionalized MWCNT based nanosensors and their characterization are strongly going to be discussed.

Keywords: Gas nanosensors; H; ₂; S in natural gas; MWCNT; MWCNT-amines; Recovery

Atomic arrangement and magnetism of iron silicide on Fe(100) surface by T.T. Suzuki; S. Hishita (pp. 166-171).

► We study surface magnetic structure of Fe(100) deposited with Si. ► The Si atoms are incorporated into the Fe subsurface via the substitutional site of bcc Fe at the Si/Fe interface. ► The reacted Si/Fe surface has an atomic arrangement similar to that of the Fe–Si plane terminated-Fe₃Si(100).We investigated surface magnetic structure in the initial stage of Si deposition on an Fe(100) surface by spin-polarized ion scattering spectroscopy (SP-ISS). We found silicidation at the Si/Fe interface after Si deposition followed by annealing at 823K. The silicidation occurs by the incorporation of silicon into the Fe substrate via the substitutional site of bcc Fe. After annealing, the incorporated Si atoms are distributed in surface layers several nanometers thick. The SP-ISS analysis revealed that the average magnetic moment of Fe in the silicide surface layer is about 70 % of that of Fe in the Fe(100) surface layer, whereas that of Si is almost zero. These surface magnetic moments are discussed in terms of the local magnetic environment. It is likely that the outermost surface of the silicide layer has an atomic arrangement similar to that of Fe₃Si(100) with surface termination by the Fe–Si plane.

Keywords: Spin-polarized ion scattering spectroscopy; Surface magnetic structure; Si/Fe interfaces

Physical properties and surface/interface analysis of nanocrystalline WO₃ films grown under variable oxygen gas flow rates by R.S. Vemuri; G. Carbjal-Franco; D.A. Ferrer; M.H. Engelhard; C.V. Ramana (pp. 172-177).

► Nanocrystalline WO₃ films were grown under variable oxygen gas flow rates. ► Surface/interface structure of WO₃ films is evaluated. ► Density variation in WO₃ films as function of oxygen reactive pressure is established. ► A correlation between TEM and XRR data is established.Nanocrystalline WO₃ films were grown by reactive magnetron sputter-deposition in a wide range of oxygen gas flow rates while keeping the deposition temperature fixed at 400°C. The physical characteristics of WO₃ films were evaluated using grazing incidence X-ray diffraction (GIXRD), X-ray reflectivity (XRR), and transmission electron microscopy (TEM) measurements. Physical characterization indicates that the thickness, grain size, and density of WO₃ films are sensitive to the oxygen gas flow rate during deposition. XRD data indicate the formation of tetragonal WO₃ films. The grain size increases from 21 to 25nm with increasing oxygen gas flow rate to 65%, at which point the grain size exhibits a decreasing trend to attain the lowest value of 15nm at 100% oxygen. TEM analysis provides a model consisting of isotropic WO₃ film (nanocrystalline)–SiO₂ interface (amorphous)–Si(100) substrate. XRR simulations, which are based on this model, provide excellent agreement to the experimental data indicating that the normalized thickness of WO₃ films decreases with the increasing oxygen gas flow rate. The density of WO₃ films increases with increasing oxygen gas flow rate.

Keywords: WO; ₃; thin films; Microstructure; Density; Surface/interface structure; X-ray reflectivity; Electron microscopy

High-speed epitaxial growth of BaTi₂O₅ thick films and their in-plane orientations by Dongyun Guo; Akihiko Ito; Rong Tu; Takashi Goto (pp. 178-185).

Display Omitted► High-speed epitaxial growth of BaTi₂O₅ thick films on MgO substrates by laser CVD. ► Epitaxial BaTi₂O₅ thick films were grown with in-plane orientations. ► In-plane orientations of epitaxial BaTi₂O₅ films can be identified crystallographically.Epitaxial BaTi₂O₅ (BT₂) thick films were prepared on (100), (110) and (111) MgO single-crystal substrates by laser chemical vapor deposition. (010)- and (112)-oriented BT₂ thick films grew epitaxially on (100) and (110) MgO substrates at deposition temperatures of 1326–1387K and 1324–1383K, respectively. On the (111) MgO substrate, BT₂ thick film showed(313¯) and(113¯) co-orientations at 1337–1353K. Epitaxial BT₂ thick films had a columnar structure in cross-section and the deposition rate reached 42μmh⁻¹. The typical in-plane orientations of the epitaxial BT₂ films were BT₂ [201¯]//MgO [01¯0] for BT₂ (010)//MgO (100), BT₂ [201¯]//MgO [001] for BT₂ (112)//MgO (110), BT₂ [101]//MgO [01¯1] for (313¯) BT₂//MgO (111), and BT₂ [301]//MgO [011¯] for (113¯) BT₂//MgO (111).

Keywords: BaTi; ₂; O; ₅; Laser CVD; Epitaxial growth; High-speed deposition

On the shot peening surface coverage and its assessment by means of finite element simulation: A critical review and some original developments by Sara Bagherifard; Ramin Ghelichi; Mario Guagliano (pp. 186-194).

► Requirements and evaluation approaches of surface coverage have been reviewed. ► The numerical models available in the literature have been statistically studied. ► A complementary technique for coverage assessment has been developed. ► The developed approach permits realistic modelling with reasonable computation time.Surface coverage is a major control parameter for shot peening and has substantial influence on the reliability and uniformity of the process. It restrains quality variations that may cause premature failure or malfunctioning of the treated part. Despite the role of surface coverage in process quality, a general description and a unique standard method for its practical control and prediction are not yet established. This paper provides a general review of the definitions and requirements of surface coverage, its practical, theoretical and computational evaluation approaches. In the end a statistical study is performed on a coverage estimation method already developed by the authors. The results of the statistical study result in development of a complementary technique for coverage assessment which ensures full coverage with an optimum number of impacts. Different models are explained and critically discussed.

Keywords: Shot peening; Surface coverage; Numerical simulation

Density functional study the interaction of oxygen molecule with defect sites of graphene by Xuejun Qi; Xin Guo; Chuguang Zheng (pp. 195-200).

► The defect sites existed on the graphite surface create active sites and enhance the reactivity of carbonaceous material. ► Oxygen molecule more favor chemisorbed on the graphene surface contains defect sites than the perfect surface. ► The single active oxygen atom adsorbed on the defect surfaces, it completely insert into the surface.The present article reports a theoretical study of oxygen interacted with graphene surface containing defect sites on the atomic level by employing the density functional theory combined with the graphene cluster model. It was founded that oxygen molecule prefers to be chemisorbed on the graphene surface containing defect sites compared to the perfect surface. The adsorption energy of O₂ on the double defect site is about 2.5 times as large as that on the perfect graphene surface. Moreover, the oxygen molecule interacts with S-W defect site gives rise to stable epoxy structure, which pulling the carbon atom outward from the original site in the direction perpendicular to the surface. If the oxygen molecule is adsorbed on the single vacancy site, two CO bonds are formed on the graphene surface. However, when the oxygen molecule is chemisorbed on the double vacancy site, the oxygen atoms substitute the missing carbon atom's position in the carbon plane and form a hexagonal structure on the graphene network. The results indicate that single active oxygen atom approaches the defect site, it's completely adsorbed in the plane and high energy is released. In all cases, the interaction of an oxygen atom with defect surface involves an exothermic process. The defect site creates active sites on the surface of graphene and produces catalytic effects during the process of oxidation of carbonaceous materials.

Keywords: Graphene; Defect site; Density functional theory; Oxidation

Preparation and characterization of magnetic gene vectors for targeting gene delivery by S.W. Zheng; G. Liu; R.Y. Hong; H.Z. Li; Y.G. Li; D.G. Wei (pp. 201-207).

► PEI is ideal candidate polymer for the design of gene delivery systems. ► PEI-CMD-MNPs exhibited a typical superparamagnetic behavior. ► PEI-CMD-MNPs were well stable over the entire range of pH and NaCl concentration. ► DNA-PEI-CMD-MNPs transfected cells by a magnet have higher transfection efficiency and gene expression efficiency.The PEI-CMD-MNPs were successfully prepared by the surface modification of magnetic Fe₃O₄ nanoparticles with carboxymethyl dextran (CMD) and polyethyleneimine (PEI). The PEI-CMD-MNPs polyplexes exhibited a typical superparamagnetic behavior and were well stable over the entire range of pH and NaCl concentration. These PEI-CMD-MNPs were used as magnetic gene vectors for targeting gene delivery.The prepared MNPs at different surface modification stages were characterized using Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), field emissions canning electron microscopy (FE-SEM), powder X-ray diffraction (XRD) and dynamic laser light scattering (DLS) analysis. The magnetic properties were studied by vibrating sample magnetometer (VSM).To evaluate the performance of the magnetic nanoparticles as gene transfer vector, the PEI-CMD-MNPs were used to delivery green fluorescent protein (GFP) gene into BHK21 cells. The expression of GFP gene was detected by fluorescence microscope. DNA-PEI-CMD-MNPs polyplexes absorbed by the cells were also monitored by Magnetic resonance imaging (MRI). The transfection efficiency and gene expression efficiency of that transfected with a magnet were much higher than that of standard transfection.

Keywords: Magnetite nanoparticle; Surface modification; Gene delivery

Anisotropic magnetization of epitaxial Ni nanogroove-arrays prepared by reduction of self-organized oxides by Akifumi Matsuda; Ryosuke Yamauchi; Geng Tan; Hirokazu Nakai; Koji Koyama; Kazuhiko Sunakawa; Satoru Kaneko; Mamoru Yoshimoto (pp. 208-212).

► Ni (111) epitaxial nanopatterns were formed on sapphire by self-organizing process. ► The nanopattern comprises thousands of straight, parallel and periodic nanogrooves. ► The process includes growth of NiO (111) by LaserMBE and annealing in air and H₂. ► The pattern retained its surface topography and epitaxy after the H₂ reduction. ► We report in-plane anisotropic magnetization behavior attributed to the morphology.A straight and periodic nanogroove-array pattern was formed on the surface of epitaxial Ni (111) thin films via a unique process, which included self-organization and reduction of oxides. In the formation of the Ni nanopattern, the epitaxial NiO (111) thin film grown on an α-Al₂O₃ (0001) substrate by laser molecular-beam epitaxy (LaserMBE) was used as a starting material. The NiO (111) films were subsequently subjected to thermal treatment at 700°C in air for the formation of self-organized nanopatterns, and then at 500°C in a hydrogen atmosphere for reducing NiO to Ni. The epitaxy and morphology of the Ni (111) nanogroove array were proved by exsitu X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. Anisotropic magnetization behavior of the Ni (111) nanogroove-array pattern was examined by a M– H measurement using a superconducting quantum interference device (SQUID) magnetometer. The M– H squareness ratios for the directions parallel and perpendicular to the nanogrooves were about 0.83 and 0.52, respectively. The coercivity along the parallel line was ∼0.5kOe, which was approximately 200% of the value for the other direction. From the magnetization results, the parallel direction was considered as the magnetic easy axis in the in-plane orientation, probably due to the shape effect.

Keywords: Nickel; Epitaxial; Hydrogen reduction; Self-organization; Ferromagnetic; Magnetic anisotropy

Annealing effects on the microstructure and magnetic domain structures of duplex stainless steel studied by in situ technique by L.Q. Guo; X.M. Zhao; M. Li; W.J. Zhang; Y. Bai; L.J. Qiao (pp. 213-218).

► The volume fraction of ferrite phase increased with increasing annealing temperature. ► The heat treatment has no effect on the crystal structure of the ferrite phase. ► The magnetic domain structure changes more obviously as annealing temperature rises. ► The ferrite grain orientations change after annealing treatments.The effects of annealing temperature on the microstructure and the magnetic domain structures of duplex stainless steel 2507 were investigated by the magnetic force microscopy (MFM), X-ray diffraction (XRD), and electron backscattered diffraction (EBSD). The MFM and XRD results indicated that the volume fraction of ferrite phase increased with increasing annealing temperature, but the lattice constants kept constant. Moreover, with the rise of annealing temperature, the magnetic domain structure in the ferrite phase varied gradually, where the magnetic domain became thinner and the distribution turned more homogeneous. These results gave a direct evidence for the changes of microstructure and magnetic domain structure induced by the annealing treatment. EBSD analysis showed that the orientation of ferrite grains changed after annealing treatments, which coincided with the changes of the microstructure and the magnetic domain structures.

Keywords: Duplex stainless steel; Magnetic domain structure; Microstructure; MFM; EBSD

Synthesis and characterization of platinum nanoparticles on carbon nanosheets with enhanced electrocatalytic activity toward methanol oxidation by Zhipeng Wang; Mao Shoji; Hironori Ogata (pp. 219-224).

► The CNS-supported Pt NPs have been firstly synthesized by one-step electrodeposition. ► The as-synthesized Pt NPs included mainly the metallic Pt of 68.9%, which plays a main role in methanol oxidation. ► The Pt/CNSs exhibited better electrocatalytic performance than the Pt/SWNTs fabricated under same conditions. ► The CNSs are promising catalyst support for fuel cells.This report describes carbon nanosheets (CNSs) were employed as a catalyst support for loading platinum nanoparticles (Pt NPs) by one-step electrodeposition. The structure, size, and chemical composition of the CNS-supported Pt NPs (Pt/CNSs) were characterized by scanning and transmission electron microscopies, energy dispersive X-ray and X-ray photoelectron spectroscopies. The electrocatalytic performances of the Pt/CNSs for methanol oxidation have been investigated by cycle votammetry and chronoamperometry. These results demonstrated the Pt/CNSs possess high electrocatalytic activity and excellent stability due to high dispersion of Pt NPs on the CNS surface and the special nature properties of CNSs. The Pt/CNSs should be a promising electrocatalyst in direct methanol fuel cells.

Keywords: Carbon nanosheets; Graphene; Platinum nanoparticles; Electrodeposition; Methanol oxidation

Local elasticity and adhesion of nanostructures on Drosophila melanogaster wing membrane studied using atomic force microscopy by Ryan Wagner; Barry R. Pittendrigh; Arvind Raman (pp. 225-230).

► We studied the wing membrane of Drosophila melanogaster with atomic force microscopy. ► We report the structure, elasticity, and adhesion on the wing membrane in air and nitrogen environments. ► Results provide insight into the nature of the wing membrane enabling the development of biomimetic surface and micro air vehicles.Insect wings have a naturally occurring, complex, functional, hierarchical microstructure and nanostructure, which enable a remarkably water-resistant and self-cleaning surface. Insect wings are used as a basis for engineering biomimetic materials; however, the material properties of these nanostructures such as local elastic modulus and adhesion are poorly understood. We studied the wings of the Canton-S strain of Drosophila melanogaster (hereafter referred to as Drosophila) with atomic force microscopy (AFM) to quantify the local material properties of Drosophila wing surface nanostructures. The wings are found to have a hierarchical structure of 10–20μm long, 0.5–1 μm diameter hair, and at a much smaller scale, 100nm diameter and 30–60nm high bumps. The local properties of these nanoscale bumps were studied under ambient and dry conditions with force-volume AFM. The wing membrane was found to have a elastic modulus on the order of 1000MPa and the work of adhesion between the probe and wing membrane surface was found to be on the order of 100mJ/m², these properties are the same order of magnitude as common thermoplastic polymers such as polyethylene. The difference in work of adhesion between the nanoscale bump and membrane does not change significantly between ambient (relative humidity of 30%) or dry conditions. This suggests that the nanoscale bumps and the surrounding membrane are chemically similar and only work to increase hydrophobicity though surface roughening or the geometric lotus effect.

Keywords: Atomic force microscopy; Insect wing; Elastic modulus

Pulse electrodeposition and characterization of nano Ni–W alloy deposits by K. Arunsunai Kumar; G. Paruthimal Kalaignan; V.S. Muralidharan (pp. 231-237).

► The alloy was found to have higher microhardness than nickel and an increase in the wt% of W in the alloy deposits. ► On the alloy surface, long needle type grains were seen. The grain size was in the range of 50–80nm. ► The EDAX analysis revealed the % of W in the alloy as 30.99%. ► The increase of W addition offered the alloy deposits enhanced corrosion resistance.Pulse plating was employed to obtain Ni–W alloy nanodeposits from ammonical citrate bath. Effects of peak current density, pH, tungstate ion concentration and temperature on the cathodic current efficiency were studied. Ni-32.8 weight (wt)% of W alloy coating was obtained using optimized bath composition. Ni–W solid solution was found in the alloy deposit. Surface morphology studies revealed that the alloy surface was covered by long needle like crystals. XRD patterns of the electrodeposits showed only fcc (nickel) peaks. The hardness of the deposits obeyed Hall–Petch relation. Electrochemical polarization studies revealed that the corrosion potentials of nickel became nobler with W addition and corrosion current density values decreased. Electrochemical impedance studies found that, the increased charge transfer resistances suggesting decreased corrosion current density values. The capacitance values of the double layer decreased with W additions.

Keywords: Nano deposits; Ni–W electrodeposits; Pulse plating; Induced co-deposition; Corrosion resistance

Effect of ammonium-salt solutions on the surface properties of carbon fibers in electrochemical anodic oxidation by Xin Qian; Xuefei Wang; Qin Ouyang; Yousi Chen; Qing Yan (pp. 238-244).

► Longitudinal grooves on the fiber surface became more well-defined and much deeper after surface treatment. ► The concentration of oxygen and nitrogen on the fiber surface increased after surface treatment. ► The intensity of oxidative reaction varied with the change of ammonium-salt solutions. ► The higher the concentration of OH⁻ ions in the electrolytes, the violent the oxidative reaction happened.The surfaces of polyacrylonitrile-based carbon fibers were treated by an electrochemical anodic method. Three different kinds of ammonium-salt solutions namely NH₄HCO₃, (NH₄)₂CO₃ and (NH₄)₃PO₄ were respectively chosen as the electrolytes. The effect of these electrolytes on the surface structure was studied by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The results showed that longitudinal grooves on the fiber surface became more well-defined and much deeper after surface treatment, and the root mean square roughness (RMS) of carbon fiber surface increased from 4.6nm for untreated fibers to 13.5nm for treated fibers in (NH₄)₃PO₄ electrolytes. The concentration of oxygen and nitrogen atomic on the fiber surface increased after surface treatment. The tensile strength of oxidized fibers had an obvious decrease, whereas the interlaminar shear strength (ILSS) value of corresponding carbon fiber reinforced polymers (CFRPs) increased in a large extent. The intensity of oxidative reaction varied with the change of ammonium-salt solutions and electrochemical oxidation in (NH₄)₃PO₄ electrolyte was of the most violence. The corresponding mechanism was also discussed and the result showed that the higher the concentration of OH⁻ ions in the electrolytes, the violent the oxidative reaction happened.

Keywords: Carbon fiber; Electrochemical anodic oxidation; Ammonium-salt solutions; Surface properties

A mechanochemical approach to get stunningly uniform particles of magnesium–aluminum-layered double hydroxides by Xiaoqing Zhang; Fenglin Qi; Shuping Li; Shaohua Wei; Jiahong Zhou (pp. 245-251).

The variation of water content can change the morphology and the dispersion state of Mg–Al-LDHs, the water content are 0% (a) and 2% (b), respectively.Display Omitted► A mechanochemical approach is developed to get uniform and monodispersed LDHs. ► This approach includes two processes, i.e., grinding and peptization process. ► Peptization plays a critical role in the formation of high crystallinity hexagons. ► The size and morphologies of LDHs can be precisely controlled.A mechanochemical approach is developed in preparing a series of magnesium–aluminum-layered double hydroxides (Mg–Al-LDHs). This approach includes a mechanochemical process which involved manual grinding of solid salts in an agate mortar and afterwards peptization process. In order to verify the LDHs structure synthesized in the grinding process, X-ray diffraction (XRD) patterns, transmission electron microscopy (TEM) photos and thermogravimetry/differential scanning calorimetry (TG–DSC) property of the product without peptization were characterized and the results show that amorphous particles with low crystallinity and poor thermal stability are obtained, and the effect of peptization is to improve the properties, more accurately, regular particles with high crystallinity and good thermal stability can be gained after peptization. Furthermore, the fundamental experimental parameters including grinding time, the molar ratio of Mg to Al element (defined as R value) and the water content were systematically examined in order to control the size and morphologies of LDHs particles, regular hexagonal particles or the spherical nanostructures can be efficiently obtained and the particle sizes were controlled in the range of 52–130nm by carefully adjusting these parameters. At last, stunningly uniform Mg–Al-LDHs particles can be synthesized under proper R values, suitable grinding time and high degree of supersaturation.

Keywords: Hybrids; Layered compounds; Intercalation reactions

On the formation of surface gallium hydride species in supported gallium catalysts by Alexander I. Serykh (pp. 252-255).

► Molecular hydrogen is dissociatively adsorbed on Ga³⁺ surface sites of supported gallium catalysts. ► The amount of hydrogen absorbed by the catalysts depend on the nature of the support. ► GaH vibration frequencies are sensitive to the nature of the support. ► The surface sites active in the dissociation of hydrogen are Ga³⁺ cations bonded to the support surface.Molecular hydrogen is dissociatively adsorbed at elevated temperatures on Ga³⁺ surface sites of supported gallium catalysts. Both the amount of hydrogen absorbed by the catalysts and GaH vibration frequencies of surface gallium hydrides formed upon dissociative hydrogen adsorption depend on the nature of the support. The surface sites, active in the dissociative adsorption of hydrogen, most probably are Ga³⁺ cations bonded to the support surface.

Keywords: Supported gallium catalysts; Gallium hydrides; Hydrogen dissociation; Hydrogen adsorption

Effects of porous nano-structure on the metal–insulator transition in VO₂ films by Yuanjie Xu; Wanxia Huang; Qiwu Shi; Yang Zhang; Yubo Zhang; Linwei Song; Yaxin Zhang (pp. 256-260).

The picture shows the morphology and hysteresis loop of porous VO₂ film: porous nano-structure with small nanoparticles is obtained, transition temperature is reduced to 56°C and hysteresis width is increased to 36°C.Display Omitted► VO₂ films with small nanoparticles and homogeneous pores are obtained. ► T_t of porous nano-structure VO₂ film is reduced to 56°C and Δ T is increased to 36°C. ► Systematic study of CTAB concentration on morphology and MIT properties of the VO₂ films is conducted.In this work, we confirmed experimentally that the porous nano-structure of vanadium dioxide (VO₂) films had significant effects on the features of the metal–insulator transition. Porous VO₂ films had been synthesized on mica substrates via a simple solution process with inorganic precursor and cetyltrimethyl ammonium bromide (CTAB). SEM images showed a combination of homogenously distributed pores and VO₂ nanoparticles. Metal to insulator transition (MIT) characteristics measurements revealed that, the porous nano-structure VO₂ films had low transition temperature, wide hysteresis width and gentle slopes of hysteresis loop. Morphologies and MIT characteristics of the films could be controlled by simply varying CTAB concentration, which is of great importance in achieving practical applications.

Keywords: Vanadium dioxide; Porous nano-structure film; Hysteresis loop; CTAB

Surface modification of poly(ethylene terephthalate) fabric via photo-chemical reaction of dimethylaminopropyl methacrylamide by Nasser H. Mohamed; Thomas Bahners; Andreas Wego; Jochen S. Gutmann; Mathias Ulbricht (pp. 261-269).

► PET fibers were UV-grafted with dimethylaminopropyl methacrylamide (DMAPMA). ► The graft yield could be controlled by irradiation time and monomer concentration. ► The tertiary amino groups of the grafted PDMAPMA were quaternized with alkyl bromides. ► The quaternization reaction had a high yield, when bromides with shorter alkyl chain were employed. ► The antimicrobial effect was highest, when samples were quaternized with 1-bromohexane and 1-bromooctane.Photo-chemical reactions and surface modifications of poly(ethylene terephthalate) (PET) fabrics with the monomer dimethylaminopropyl methacrylamide (DMAPMA) and benzophenone (BP) as photo-initiator using a broad-band UV lamp source were investigated. The tertiary amino groups of the grafted poly(DMAPMA) chains were subsequently quaternized with alkyl bromides of different chain lengths to establish antibacterial activity. The surface composition, structure and morphology of modified PET fabrics were characterized by Fourier transform infrared spectroscopy (FTIR/ATR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). To evaluate the amount of quaternary and tertiary ammonium groups on the modified surface, PET was dyed with an acid dye which binds to the ammonium groups. Therefore, the color depth is a direct indicator of the amount of ammonium groups. The resulting antibacterial activity of the modified PET fabrics was tested with Escherichia coli. The results of all experiments show that a photochemical modification of PET is possible using DMAPMA, benzophenone and UV light. Also, the quaternization of tertiary amino groups as well as the increase in antibacterial activity of the modified PET by the established quaternary ammonium groups were successful.

Keywords: Photo-chemical surface modification; UV-grafting; Quaternization; Antibacterial activity

Characterization and hydrogen gas sensing properties of TiO₂ thin films prepared by sol–gel method by Azhar Ali Haidry; Jarmila Puskelova; Tomas Plecenik; Pavol Durina; Jan Gregus; Martin Truchly; Tomas Roch; Miroslav Zahoran; Melinda Vargova; Peter Kus; Andrej Plecenik; Gustav Plesch (pp. 270-275).

Display Omitted► Preparation and characterization of hydrogen sensing TiO₂ thin films by sol–gel method. ► The annealing effect on the structure, electrical, optical and sensing properties was studied. ► The best sensitivity show the films composed of rutile with grain size of ∼100nm.Thin films of titanium dioxide with thickness of about 150nm were deposited by spin coating method on a sapphire substrate from a sol–gel and annealed at various temperatures (from 600°C to 1000°C). Structural, optical and hydrogen gas sensing properties of the films were investigated. The annealing temperatures from 600 to 800°C led to anatase phase with grain size in the range of 14–28nm. Further increase of the annealing temperature resulted in transformation to rutile phase with larger grain size of about 100–120nm. The optical band gap tended to decrease with increasing annealing temperature. The estimated values of activation energy for charge transport were in the range of 0.6–1.0eV for films annealed at temperatures from 600°C to 800°C and 0.37–0.38eV for films annealed at 900°C and 1000°C. The films annealed at 900°C and 1000°C showed better hydrogen sensitivity, what can be at least partially caused by their higher surface roughness.

Keywords: TiO; ₂; Sol–gel; Annealing effect; Grain size; Surface roughness; Band gap; Activation energy; Hydrogen gas sensor

Briefly brominated Ag thin films: XRD, FESEM, and optical studies of surface modification by D. Rajesh; C.S. Sunandana (pp. 276-282).

Display Omitted► Simple rapid effective strategy of brief exposure to Br vapours of Ag films produces surface modification. ► The optical absorption of the samples manifests the SPR phenomena, which is very sensitive to Br time. ► The number density of Ag particles decreases even as their mean size increases upon bromination. ► Brief bromination modifier is widely applicable for semiconducting material devices, sensor and plasmonic technologies.Nanoparticulate silver thin films have been prepared on glass substrates by thermal evaporation and their surface modification was triggered by brief (<10min) bromination carefully monitored ex situ using structural, microscopic and optical probes. X-ray diffraction reveals that this sample remains amorphous even after brief bromination which gave the crystallinity of Ag. The optical absorption of the samples manifests the surface plasmon resonance (SPR) phenomena, which is very sensitive to bromination time and also varies with Ag film thickness. The number density of Ag particles decreases even as their mean size increases upon bromination. Optimization of the bromination process of a new type of plasmonic material could lead to applications in sensor, SERS-active substrates and plasmonic technologies.

Keywords: Surface modification; Ag thin films; Bromination; SPR; Brominated Ag thin films

Influence of mechanical and chemical surface treatments on the formation of bone-like structure in cpTi for endosseous dental implants by Farhang Parsikia; Pupak Amini; Sirous Asgari (pp. 283-287).

► Acid–alkali process after grit blasting showed optimized surface morphology. ► The reverse sequence yields inferior bioactivity and improved biocompatibility. ► Surface morphology was most uniform after a final grit blasting stage.Commercially pure titanium samples were exposed to grit blasting and acid–alkali treatments to obtain a variety of surface compositions and morphologies. Contact roughness test and microstructural studies were employed to study the surface topography of the samples. The nature and chemical composition of surface phases were evaluated using X-ray diffraction and microanalysis techniques. Selected samples first exposed to in vitro environment were then tested to determine the surface morphology and surface microstructure. Based on the data presented in this work, it is suggested that grit blasting process utilized prior to chemical treatment stage, yields a high quality surface morphology. Such a surface morphology is expected to have superior tribological characteristics after osseointegration. Also, it appeared that the reverse sequence of processing resulted in a better biocompatibility of the product manifested by negligible amount of residual alumina on the sample surface.

Keywords: In vitro; Surface topography; Acid–alkali treatment; Grit blasting; cpTi

Effect of surface modification on carbon fiber and its reinforced phenolic matrix composite by Hua Yuan; Chengguo Wang; Shan Zhang; Xue Lin (pp. 288-293).

► We used very simple and effective modification method to treat PAN-based carbon fiber by liquid oxidation and coupling agent. ► Carbon fiber surface functional groups were analyzed by LRS and XPS. ► Proper treatment of carbon fiber can prove an effective way to increase composite's performance. ► Carbon fiber surface modifications by oxidation and APS could strengthen fiber activity and enlarge surface area as well as its roughness.In this work, polyacrylonitrile (PAN)-based carbon fiber were chemically modified with H₂SO₄, KClO₃ and silane coupling agent (γ-aminopropyltriethoxysilane, APS), and carbon fiber reinforced phenolic matrix composites were prepared. The structural and surface characteristics of the carbon fiber were investigated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), laser Raman scattering (LRS) and Fourier transform infrared spectroscopy (FTIR). Single fiber mechanical properties, specific surface area, composite impact properties and interfacial shear strength (ILSS) were researched to indicate the effects of surface modification on fibers and the interaction between modified fiber surface and phenolic matrix. The results showed that carbon fiber surface modification by oxidation and APS can strengthen fiber surface chemical activity and enlarge the fiber surface area as well as its roughness. When carbon fiber (CF) is oxidized treatment, the oxygen content as well as the O/C ratio will be obviously increased. Oxygen functional groups increase with oxidation time increasing. Carbon fiber treated with APS will make COR content increase and OCO content decrease due to surface reaction. Proper treatment of carbon fiber with acid and silane coupling agent prove an effective way to increase the interfacial adhesion and improve the mechanical and outdoor performance of the resulting fiber/resin composites.

Keywords: Carbon fiber; Surface modification; Silane coupling agent; Impact properties

Deformation behavior of the oxide film on the surface of cold sprayed powder particle by Shuo Yin; Xiaofang Wang; Wenya Li; Hanlin Liao; Hongen Jie (pp. 294-300).

► The formation of the metal jet helps to remove the cracked oxides from the interface. ► Part of the cracked oxides remains at the central region of the interface. ► Substrate hardness, particle velocity and spray angle affect the oxide film deformation. ► The remaining oxides accumulate at one side of the interface for angular impacting. ► The oxides remaining at the interparticle interface exist at the entire interface.In cold spraying, oxide-free interface is an important factor for metal-to-metal contact between powder particles and substrate, which determines the bonding strength and final coating quality. In this study, a systematic finite element analysis (FEA) is performed to examine the deformation behavior of the oxide film on an Al 6061-T6 particle surface after deposition. The simulation results show that the oxide film can be disrupted during the high velocity impact. Part of the cracked oxides remains at the interface and mainly accumulates at the central region after particle deposition. Substrate hardness, particle velocity and spray angle are found to influence the deformation behavior and final state of the oxide film. Besides, interparticle interaction is also investigated in the present work to clarify the deformation behavior of the oxide film inside the coating.

Keywords: Cold spraying (CS); Finite element analysis (FEA); Numerical simulation; Euler method; Oxide film; High velocity impact

Enhanced spectral emissivity of CeO₂ coating with cauliflower-like microstructure by Jianping Huang; Yibin Li; Xiaodong He; Guangping Song; Chenglei Fan; Yue Sun; Weidong Fei; Shanyi Du (pp. 301-305).

► Cauliflower-like microstructured CeO₂ coating is prepared on Ni based substrate. ► The infrared emissive property at high temperature is investigated. ► Rough CeO₂ coating shows high emissivity, that is, 0.9 at 873K and 0.87 at 1073K. ► The emissivity enhancement mechanisms for the rough CeO₂ coating are discussed.Cerium dioxide is a transparent oxide with high refractive index (from 1.6 to 2.5 at 633nm) in the visible and near-IR spectral regions. However, little attention has been paid to its optical property in mid-IR (2.5–25μm). Here we report that the cauliflower-like microstructured CeO₂ coating deposited by electron beam physical vapor deposition technique shows high emissivity up to 0.9 at 873K in the mid-IR spectral region. The high emissivity is attributed to the coupling between free propagating waves and space-variant polarizations caused by the cauliflower-like microstructure. This high emissivity coating shows a potential application in high temperature components.

Keywords: CeO; ₂; coating; Cauliflower-like microstructure; Emissivity; Surface

Hydrothermal synthesis and characterization of single crystalline Cu-doped α-FeOOH nanowires by Nengmei Shen; Xiaomin Xiang; Xichun She; Yong Yang; Yongwang Li (pp. 306-310).

► We have successfully prepared Cu-doped α-FeOOH nanowires with diameters of 30–40nm and lengths up to 1μm under mild hydrothermal conditions. ► Nanowires are single-crystalline with an oriented growth along the [130] direction. ► The Cu-dopant content could significantly affect the morphologies and crystalline phases of products.Cu-doped α-FeOOH nanowires with diameters of 30–40nm and lengths up to 1μm were synthesized by a convenient hydrothermal method under mild conditions. X-ray powder diffraction (XRD) and high-resolution TEM (HRTEM) studies indicated that nanowires were single-crystalline with an oriented growth along the [130] direction. The effects of Cu-dopant content on the morphologies and crystalline phases characterized by field emission scanning electron microscopy (FE-SEM), Mössbauer and Fourier transform infrared (FT-IR) spectroscopies were also investigated. Obtained results indicated that α-(Fe,Cu)OOH nanowires were formed up to x=2.5, whereas α-(Fe,Cu)₂O₃ nanocubes alone were obtained at x=10, where m(Fe:Cu)=100: x.

Keywords: Hydrothermal synthesis; α-FeOOH nanowires; Cu-dopant; Single-crystalline; Mössbauer spectroscopy

Titanium alloy nanosecond vs. femtosecond laser marking by Stefan Rusu; Aurelian Buzaianu; Laura Ionel; Daniel Ursescu; Dan Gelu Galusca (pp. 311-319).

► We analyze nanosecond (commercial) and femtosecond laser marks, using SEM and EDAX. ► Elevated repetitive thermal gradients leads to structural defects for double crosses. ► Femtolaser engraving forms amorphous structures, composed of spherical particles. ► We conduct X-ray diffractometry to detect internal micro and residual stresses. ► No internal stresses modification occurred for nano and femtosecond laser marking.There are few papers which aim to analyze the effects of laser marking for traceability on various materials; therefore, the present paper proposes a study of the influences of such radiation processing on a titanium alloy, a vastly used material base within several industry fields. For the novelty impact, femtolaser marking has been carried out, besides the commercial nanosecond standard engraving. All marks have been analyzed using scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffractometry.

Keywords: Laser; Marking; Titanium; Nanosecond; Femtosecond

Electronic resonance and photoemission study of nitrogen doped TiO₂ rutile (110) single crystals by Isao Takahashi (pp. 320-323).

Display Omitted► A low concentration of oxygen vacancies and hybridization of the O2p/N2p with the Ti 3d/4sp levels. ► The electronegativity of the nitrogen, which moves the electrons of O2p, O2s, Ti3d, and Ti4s to lower binding energy sites. ► The distribution of the nitrogen is dependent on the depth profile and shows a higher concentration near the surface.The electronic structure of nitrogen doped TiO₂ was investigated by ultraviolet photoemission spectroscopy and soft X-ray photoemission spectroscopy. Single crystal rutile (110) samples were prepared by annealing in an ammonia atmosphere and subsequently annealed to different temperatures in an argon atmosphere. This procedure leads to a low concentration of oxygen vacancies. Resonant photoemission indicates hybridization of the O2p/N2p with the Ti 3d/4sp levels.

Keywords: Electronic resonance; N-doped rutile (1; 1; 0); Photoemission

Fabrication of anodic aluminum oxide with incorporated chromate ions by Wojciech J. Stępniowski; Małgorzata Norek; Marta Michalska-Domańska; Aneta Bombalska; Agata Nowak-Stępniowska; Mirosław Kwaśny; Zbigniew Bojar (pp. 324-330).

► Anodic aluminum oxide was formed by anodization in 0.3M chromic acid. ► Influence of operating conditions on chromate anions incorporation was studied. ► Photoluminescence of anodic alumina with incorporated chromate ions was studied. ► Qualitative arrangement analysis of pores was done. ► an influence of operating conditions on nanopores geometry was investigated.The anodization of aluminum in 0.3M chromic acid is studied. The influence of operating conditions (like anodizing voltage and electrolyte's temperature) on the nanoporous anodic aluminum oxide geometry (including pore diameter, interpore distance, the oxide layer thickness and pores density) is thoroughly investigated. The results revealed typical correlations of the anodic alumina nanopore geometry with operating conditions, such as linear increase of pore diameter and interpore distance with anodizing voltage. The anodic aluminum oxide is characterized by a low pores arrangement, as determined by Fast Fourier transforms analyses of the FE-SEM images, which translates into a high concentration of oxygen vacancies. Moreover, an optimal experimental condition where chromate ions are being successfully incorporated into the anodic alumina walls, have been determined: the higher oxide growth rate the more chromate ions are being trapped. The trapped chromate ions and a high concentration of oxygen vacancies make the anodic aluminum oxide a promising luminescent material.

Keywords: Anodization; Anodic aluminum oxide; AAO; Self-organization; Ions incorporation; Photoluminescence

Tunable ion-swelling for nanopatterning of macroscopic surfaces: The role of proximity effects by N. Nagy; Z. Zolnai; E. Fülöp; A. Deák; I. Bársony (pp. 331-337).

Display Omitted► Utilizing ion irradiation and nanosphere lithography to induce local swelling on Si. ► Pattern height and curvature were tailored by the mask and irradiation parameters. ► Proximity exposure effect calculations to predict the radial ion fluence distribution. ► Good agreement between AFM profiles and ion fluence distributions. ► Surface profiles were predicted for several particle shapes, sizes, and ion energies.Ordered surface nanopatterns with different spatial periods and various characters were prepared on silicon surfaces by masked ion irradiation utilizing the local ion-swelling effect. Langmuir–Blodgett (LB) monolayers of hexagonally arranged Stöber silica particles as nanomasks were applied on large area Si substrates during Ar⁺ or Xe²⁺ exposure with different fluences. We show that the height and curvature of surface swelling patterns can be tuned by appropriate selection of the particle diameter, ion energy, and ion fluence. It is also revealed that the ion beam-induced anisotropic deformation of the silica mask can be exploited to tailor the surface geometry. We point that, having knowledge on the diameters and average spacing between the silica particles as extrinsic beam spreading factors, and considering the lateral straggling of the bombarding ions in the mask and in the substrate material as intrinsic beam spreading factors, a simple model of the radial fluence distribution can be applied to predict the main features of irradiation-induced surface patterns. The role of proximity effects in the potential use of this easy, fast, wafer-scale nanofabrication method is discussed.

Keywords: Nanopatterning; Nanosphere lithography; Ion-implantation; Local swelling; Proximity effects

Measuring the adhesion of alumina coatings onto Fecralloy supports using a mechanical testing system by S.A. Adegbite (pp. 338-342).

.Display Omitted► Automatic film application is used for coating γ-alumina slurries onto Fecralloy^®. ► A mechanical system was used for measuring coating adherence. ► At 40wt% solids concentration, the finest coatings showed the best adherence. ► Finer coatings exhibited cohesive failure arising from internal coating fractures.Tightening legislation for vehicles across the world has caused the use of monolith catalysts in automotive emission control to become ubiquitous. Control of the surface adhesion of the platinum group metal (PGM) coating onto the monolith block, to maximise catalytic performance for a minimum PGM loading, is therefore paramount. In this paper, an automatic film application is used for coating γ-alumina slurries onto Fecralloy^®, an integral component of metallic monolith catalysts, to achieve the desired coating properties. A newly devised dual compression–tension technique using a mechanical testing system (MTS) is used for measuring the coating adhesion. This method involves compression of the coating with a probe at a fixed load, and then removing the probe together with the coating at right angles to the substrate surface at a speed of 10mm/min. The MTS results are compared with those from conventional ultrasonic vibration tests. It is found that at 40wt% solids concentration, the coatings of the finest particles ( d_0.9 of 12.14μm) showed the best adhesion with an ultimate strength of 0.59MPa and 85–90mass% coating removal.

Keywords: Fecralloy; Adhesion; Coating; Alumina; Support; Mechanical; Catalyst

Reactive wetting of AgCuTi filler metal on the TiAl-based alloy substrate by Yulong Li; Wen Liu; Dusan P. Sekulic; Peng He (pp. 343-348).

► The wetting of AgCuTi on both polished and rough TiAl feature similar kinetics. ► Wetting kinetics within the main spreading stage features a power law of Rⁿ∼ t ( n=1). ► The reaction between the AgCuTi and TiAl controls the spreading process.Reactive wetting of the AgCuTi over a TiAl substrate was investigated by hot stage microscopy in real-time in situ, under a high purity argon atmosphere at an elevated temperature (∼1270K level). The results show: wetting process of the AgCuTi alloy on both polished and rough surfaces feature similar kinetics. Three stages were identified, (i) initial stage upon the onset of melting characterized with triple line essentially stationary or contracting, (ii) middle stage featuring almost linear spreading kinetics, and (iii) asymptotic stage with kinetics with diminishing spreading rate. Wetting kinetics within the main spreading stage features the power law of Rⁿ∼ t ( n=1). During spreading, Ag-based solid solution and Al–Cu–Ti ternary intermetallics were formed along the interface within the joint zone. Therefore, the spreading of AgCuTi filler over TiAl is highly reactive and the topographical modification of the base metal surface may have a minimal impact on wetting process.

Keywords: TiAl; Wetting kinetics; Interfaces; Brazing; Microstructure

Environmental remediation and superhydrophilicity of ultrafine antibacterial tungsten oxide-based nanofibers under visible light source by Chutima Srisitthiratkul; Wittaya Yaipimai; Varol Intasanta (pp. 349-355).

Nanosilver-decorated WO₃ photocatalytic nanofibers are antibacterial and superhydrophilic under a visible light source.Display Omitted► Deposition of nanosilver onto electrospun WO₃ nanofibers’ surface was done exploiting visible or UV light driven photoreduction of silver ion. ► Nanofibers showed antibacterial characteristics. ► Nanofibers degraded a model toxin effectively. ► Nanofibers showed superhydrophilicity under a visible light source.Fabrication of nanosilver-decorated WO₃ nanofibers was successfully performed. First, deposition of nanosilver onto electrospun WO₃ nanofibers’ surface was done via photoreduction of silver ion under visible or UV light. The resulting hybrid nanofibers not only revealed antibacterial characteristics but also maintained their photocatalytic performance towards methylene blue decomposition. Unexpectedly, the nanofibrous layers prepared from these nanofibers showed superhydrophilicity under a visible light source. The nanofibers might be advantageous in environmental and hygienic nanofiltration under natural light sources, where the self-cleaning characteristics could be valuable in maintenance processes.

Keywords: Tungsten oxide; Nanofibers; Electrospinning; Silver; Nanoparticles; Staphylococcus aureus; Escherichia coli; Wetting; Superhydrophilicity; Self-cleaning

Phosphoric chemical conversion coating with excellent wax-repellent performance by Yuzhen Guo; Weiping Li; Liqun Zhu; Zhiwei Wang; Huicong Liu (pp. 356-361).

► A novel wax-repellent coating was developed. ► The coating takes h phase (Zn₃(PO₄)₂(H₂O)₄) as primary composition. ► Water-wetting property of the coating is a key factor in suppressing wax deposition. ► The weak affinity between coating and wax is also important in reducing deposition.Wax deposition on pipelines is a serious problem for the production of crude oil. In this paper, phosphoric chemical conversion coatings were exploited to solve the problem. The chemical conversion coatings were fabricated on carbon substrate by surface modification technology at different temperature. A self-designed wax deposition apparatus based on cold-finger was used to study the wax-repellent properties of coatings, which indicated that all chemical conversion coatings showed superior wax-repellent performance to bare carbon substrate and the wax deposition reduction value of 80–95% was achieved by the chemical conversion coating obtained at room temperature. The microstructure and composition of coatings were evaluated by SEM and XRD, revealing that there existed much difference in the content of Zn₃(PO₄)₂(H₂O)₄ phase and the microstructure among different coatings. The contact angle results measured on a contact angle meter showed that all coatings belonged to hydrophilic surface. And the study on the wetting behavior of Zn₃(PO₄)₂(H₂O)₄ phase suggested that the water wetting property of coating was a key factor for suppressing wax deposition and the weak affinity between coating and wax also played an important role.

Keywords: Wax deposition; Chemical conversion coating; Wax-repellent performance

High-compactness coating grown by plasma electrolytic oxidation on AZ31 magnesium alloy in the solution of silicate–borax by M.J. Shen; X.J. Wang; M.F. Zhang (pp. 362-366).

► The MgO ceramic coating has been prepared on the surface of AZ31 magnesium alloy by plasma electrolytic oxidation in the borax-doped silicate system. ► Boron element exists in the PEO films in the form of noncrystal. ► The microhardness and compactness of doped ceramic coating are much higher than that of the substrate and undoped ceramic coating, and this doped coated sample shows better wear-resisting property.A ceramic coating was formed on the surface of AZ31 magnesium alloy by plasma electrolytic oxidation (PEO) in the silicate solution with and without borax doped. The composition, morphology, elements and roughness as well as mechanical property of the coating were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectrometry (EDS), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and reciprocal-sliding tribometer. The results show that the PEO coating is mainly composed of magnesia. When using borax dope, boron element is permeating into the coating and the boron containing phase exist in the form of amorphous. In addition, the microhardness and compactness of the PEO coating are improved significantly due to doped borax.

Keywords: Plasma electrolytic oxidation; Magnesium alloy; Surface; PEO coating

FT-IR spectroscopic and thermodynamic study on the adsorption of carbon dioxide and dinitrogen in the alkaline zeolite K-L by C.O. Arean; G.F. Bibiloni; M.R. Delgado (pp. 367-370).

► Variable temperature IR spectroscopy is used to study adsorption of CO₂ and N₂ in the alkaline zeolite K-L. ► By simultaneously recording IR absorbance, temperature and equilibrium pressure, standard adsorption enthalpy and entropy for each gas was determined. ► The results are discussed in the broader context of gas separation using zeolites; focusing on carbon dioxide capture.The thermodynamics of carbon dioxide and dinitrogen adsorption on the zeolite K-L was investigated by means of variable temperature IR spectroscopy, a technique that affords determination of standard adsorption enthalpy (Δ H°) and entropy (Δ S°) from analysis of IR spectra recorded over a temperature range while simultaneously measuring equilibrium pressure inside a closed IR cell. Δ H° resulted to be −42.5 and −20.6kJmol⁻¹ for CO₂ and N₂, respectively. Corresponding values of Δ S° were found to be −182 and −151Jmol⁻¹K⁻¹. The obtained adsorption enthalpy values are discussed in the context of carbon dioxide capture and sequestration.

Keywords: Carbon dioxide adsorption; CCS; IR spectroscopy; Nitrogen adsorption; Thermodynamics; Zeolites

The chemical characterization and reflectivity of the Al(1.0%wtSi)/Zr periodic multilayer by Qi Zhong; Zhong Zhang; Jingtao Zhu; Zhanshan Wang; Philippe Jonnard; Karine Le Guen; Jean-Michel André (pp. 371-375).

► We use XPS and XRD to research the structure of the multilayer. ► Four impact factors are responsible for the loss of theoretical reflectivity. ► Through the EUV simulation, the simulated reflectivities of factors are presented.The reflectivity of Al(1.0%wtSi)/Zr multilayer with 40 periods has been measured in the region of 17–19nm. Experimental peak reflectivity is 41.2% at 5° incidence angle. However, the corresponding theoretical value for an ideal Al(1.0%wtSi)/Zr multilayer is 70.9%. In order to explain the difference between theoretical and experimental reflectivity, the multilayer has been characterized by X-ray diffraction and X-ray photoelectron spectroscopy. Based on this analysis, the four impact factors responsible for the loss of reflectivity are inhomogeneous crystallization of aluminum, contamination of the multilayer, surface oxidized layer and interdiffusion between Al and Zr layers. The effects of different impact factors on the EUV reflectivity of the Al(1.0%wtSi)/Zr multilayer have been introduced independently by means of corresponding simulations.

Keywords: Al(1.0%wtSi)/Zr multilayer; EUV reflectivity; XPS; Interface; Simulation

Adsorption and release of amino acids mixture onto apatitic calcium phosphates analogous to bone mineral by A. El Rhilassi; M. Mourabet; H. El Boujaady; M. Bennani-Ziatni; R. El Hamri; A. Taitai (pp. 376-384).

► The adsorption kinetics is very fast while the release kinetics is slow. ► The composition of the hydrated surface layer has an influence on the interactions. ► The interaction processes is affected by competition between the amino acids. ► The adsorption is electrostatic type. ► The release is performed by exchange reactions.Study focused on the interaction of adsorbate with poorly crystalline apatitic calcium phosphates analogous to bone mineral. Calcium phosphates prepared in water-ethanol medium at physiological temperature (37°C) and neutral pH, their Ca/P ratio was between 1.33 and 1.67. Adsorbate used in this paper takes the mixture form of two essential amino acidsl-lysine anddl-leucine which have respectively a character hydrophilic and hydrophobic. Adsorption and release are investigated experimentally; they are dependent on the phosphate type and on the nature of adsorbatel-lysine,dl-leucine and their mixture. Adsorption of mixture of amino acids on the apatitic calcium phosphates is influenced by the competition between the two amino acids:l-lysine anddl-leucine which exist in the medium reaction. The adsorption kinetics is very fast while the release kinetics is slow. The chemical composition of apatite has an influence on both adsorption and release. The interactions adsorbate–adsorbent are electrostatic type. Adsorption and release reactions of the amino acid mixture are explained by the existence of the hydrated surface layer of calcium phosphate apatite. The chargedCOO andNH₃⁺ of adsorbates are the strongest groups that interact with the surface of apatites, the adsorption is mainly due to the electrostatic interaction between the groupsCOO of amino acids and calcium Ca²⁺ ions of the apatite. Comparative study of interactions between adsorbates (l-lysine,dl-leucine and their mixture) and apatitic calcium phosphates is carried out in vitro by using UV–vis and infrared spectroscopy IR techniques.

Keywords: Release; Adsorption; l; -Lysine; dl; -Leucine; Mixture; Calcium phosphate; Hydrated surface layer

Angle resolved XPS of monomolecular layer of 5-chlorobenzotriazole on oxidized metallic surface by L.P. Kazansky; I.A. Selyaninov; Yu.I. Kuznetsov (pp. 385-392).

Display Omitted► Adsorption of 5-chloroBTA on oxidized metals is studied by ARXPS. ► When adsorbed, 5-chloroBTA forms a monolayer whose thickness is close to molecule size. ► According to ARXPS, the planes of 5-chloroBTA anions are vertical to a metal oxide surface. ► Metal cations of the surface coordinate nitrogen atoms of 5-chloroBTA. ► Chlorine atoms forming outmost virtual layer.Angle resolved XPS is used to study adsorption of 5-chlorobenzotriazole (5-chloroBTAH) on surfaces of the oxidized metals: mild steel, copper and zinc from borate buffer solution (pH 7.4). It is shown that for the metals studied the 5-chloroBTA anions, when adsorbed, form a monomolecular layer whose thickness is ∼6Å comparable with the size of BTA. As XPS evidences adsorption proceeds with deprotonation of 5-chloroBTAH and formation of the coordination bonds between the lone pair of nitrogens and cation of a metal. Measuring XPS at two different angles unequivocally points out almost vertical arrangement of the anions toward the sample surface, when chlorine atoms form outmost virtual layer.

Keywords: Adsorption; 5-ChloroBTA; Mild steel; Copper; Zinc; AR-XPS

The effects of ZnO layer and annealing temperature on the structure, optical and film–substrate cohesion properties of SiGe thin films prepared by radio frequency magnetron sputtering by Jinsong Liu; Ziquan Li; Kongjun Zhu; Mingxia He; Mengqi Cong; Shuo Zhang; Jie Peng; Yani Liu (pp. 393-398).

► ZnO/SiGe thin films were obtained by using radio frequency magnetron sputtering method and following annealing process at different temperatures. ► The XRD and SEM results showed that the additional ZnO layer and annealing behavior could effectively improve the crystallinity of the films. ► The UV–vis absorption spectra indicated that the optical absorption intensity or range of the films was enhanced. ► Film–substrate cohesion property test showed that critical loading L_c values of the ZnO/SiGe films were almost in accordance with those of the SiGe films when annealing temperature T_an is increased to 700 and 800°C.ZnO/SiGe thin films were prepared by radio frequency magnetron sputtering. The effects of the ZnO layer and the annealing temperature on the structure, optical absorption and film–substrate cohesion properties of the films were investigated by XRD, SEM, UV–vis and coating adhesion automatic scratch tester. The results indicated that the additional ZnO layer and the annealing behavior could effectively improve the crystallinity of the SiGe films, and enhance the optical absorption intensity or range of the films. The film–substrate cohesion property test showed that critical loading L_c values of the ZnO/SiGe films were almost in accordance with those of the SiGe films when annealing temperature T_an is increased to 700 and 800°C.

Keywords: ZnO/SiGe thin films; Magnetron sputtering; Optical absorption; Film–substrate cohesion

Comparative study of the ZnO and Zn1−_xCd_xO nanorod emitters hydrothermally synthesized and electrodeposited on p-GaN by O. Lupan; T. Pauporté; L. Chow; G. Chai; B. Viana; V.V. Ursaki; E. Monaico; I.M. Tiginyanu (pp. 399-405).

Display Omitted► Rapid hydrothermal seed layer-free synthesis (15min) of epitaxial ZnO and n-Zn1−_xCd_x O nanorod arrays on p-GaN(0001). ► The effects of hydrothermal versus electrochemical deposition synthesis on the optical properties of ZnO nanorods on GaN substrate are reported in details. ► The hetero-structures were used for LED applications. With hydrothermal-ZnO and electrodeposited-ZnO, UV-emission started at low forward voltage of 3.9–4.0V and 4.4V. ► It was demonstrated that a single short wavelength emission shifted to the violet range with Cd-alloying of ZnO nanorods by hydrothermal technique.Hydrothermal synthesis and electrodeposition are low-temperature and cost-effective growth techniques of high quality nanostructured active materials for opto-electronic devices. Here we report a hydrothermal seed layer-free and rapid synthesis (15min) of epitaxial nanorod arrays of ZnO on p-GaN(0001). The effects of hydrothermal (HT) versus electrochemical deposition (ECD) synthesis on the optical properties of ZnO nanorods/nanowires on p-GaN substrate are compared in details. For both types of layers, a strong photoluminescent UV-emission was found indicating the high quality of the synthesized ZnO layer. The hetero-structures were used for LED applications. With HT-ZnO and ECD-ZnO, UV-emission started at remarkably low forward voltage of 3.9–4.0V and 4.4V respectively and increased rapidly. Moreover, the LED structures showed a stable and repeatable electroluminescence. We propose for further studies a simple, efficient, seed layer-free and low temperature hydrothermal growth technique to fabricate high quality ZnO nanorods/ p-GaN heterojunction LED nanodevices. It is also demonstrated that a single short wavelength emission can be shifted to the violet range with Cd-alloying of ZnO used for LED structure.

Keywords: ZnO Nanorods; Hydrothermal growth; Electrochemical deposition; Epitaxy; Photoluminescence; UV-light emitting diode; LED; ZnO/; p; -GaN heterojunction

Ultra-fast photo-patterning of hydroxamic acid layers adsorbed on TiAlN: The challenge of modeling thermally induced desorption by Maximilian Hemgesberg; Simon Schütz; Christine Müller; Matthias Schlörholz; Harald Latzel; Yu Sun; Christiane Ziegler; Werner R. Thiel (pp. 406-415).

Display Omitted► Different hydroxamic acids are suitable for the hydrophobization of TiAlN surfaces used in photo-patterning applications. ► The binding strength of the surfactant on the surface is dependent on the hydrogen and π-bonding interactions within the organic layer. ► Thermal desorption of selected HA species results in a 20% energy reduction compared to alkyl phosphates.Long-chain n-alkyl terminated hydroxamic acids (HA) are used for the modification of titanium aluminum nitride (TiAlN) surfaces. HA coatings improve the hydrophobicity of this wear resistant and industrially relevant ceramic. Therefore, HAs with different structural properties are evaluated with respect to their wear resistance and their thermal desorption properties. In order to find new coatings for rewritable offset printing plates, the changes in the surface polarity, composition, and morphology are analyzed by contact angle measurements, X-ray photoemission spectroscopy (XPS), and scanning force microscopy (SFM), respectively. The results are referenced to the strongly bonding molecule n-dodecyl phosphonate (PO11M), which has been used for surface hydrophobization before but proved difficult to remove due to the high laser outputs required for thermal desorption. It is found that for certain HAs, an equally good hydrophobization compared to PO11M can be achieved. Contact angles obtained for different hydroxamic acid coatings can be correlated to their modes of adsorption. Only for selected HA species, resistance to mechanical wear is sufficient for further investigations. Photo-patterning of these hydroxamic acid layers is achieved using a high energy IR laser beam at different energy inputs. Fitting of the obtained data and further evaluation using finite element analysis (FEM) calculations reveal significantly reduced energy consumption of about 20% for the removal of a specific hydroxamic acid coating from the ceramic surface compared to PO11M.

Keywords: Spray-coating; Photo-patterning; Hydroxamic acids; Phosphonic acids; Titanium aluminum nitride; Surface modification

Characterization of a poly(ether urethane)-based controlled release membrane system for delivery of ketoprofen by Doina Macocinschi; Daniela Filip; Stelian Vlad; Ana Maria Oprea; Carmen Anatolia Gafitanu (pp. 416-423).

► Ketoprofen incorporation in poly(ether urethane) microporous membrane. ► Moisture sorption properties of as-cast membrane. ► Drug release mechanisms in function of pH and composition of membranes.A poly(ether urethane) based on polytetrahydrofuran containing hydroxypropyl cellulose for biomedical applications was tested for its biocompatibility. Ketoprofen was incorporated (3% and 6%) in the polyurethane matrix as an anti-inflammatory drug. Kinetic and drug release mechanisms were studied. The pore size and pore size distribution of the polyurethane membranes were investigated by scanning electron microscopy. Surface tension characteristics as well as moisture sorption properties such as diffusion coefficients and equilibrium moisture contents of the membrane material were studied. It was found that kinetics and release mechanisms are in function of medium pH, composition of polymer–drug system, pore morphology and pore size distribution. Prolonged nature of release of ketoprofen is assured by low amount of drug in polyurethane membrane and physiological pH.

Keywords: Polyurethane biomaterial; Ketoprofen; Membrane; Moisture sorption; Controlled release drug delivery; Surface tension

Hydrophilic property of 316L stainless steel after treatment by atmospheric pressure corona streamer plasma using surface-sensitive analyses by Ibrahim Al-Hamarneh; Patrick Pedrow; Asma Eskhan; Nehal Abu-Lail (pp. 424-432).

► Surface hydrophilic property of surgical-grade 316L stainless steel was enhanced by Ar–O₂ corona streamer plasma treatment. ► Hydrophilicity, surface morphology, roughness, and chemical composition before and after plasma treatment were evaluated. ► Contact angle measurements and surface-sensitive analyses techniques, including XPS and AFM, were carried out. ► Optimum plasma treatment conditions of the SS 316L surface were determined.Surgical-grade 316L stainless steel (SS 316L) had its surface hydrophilic property enhanced by processing in a corona streamer plasma reactor using O₂ gas mixed with Ar at atmospheric pressure. Reactor excitation was 60Hz ac high-voltage (0–10kV_RMS) applied to a multi-needle-to-grounded screen electrode configuration. The treated surface was characterized with a contact angle tester. Surface free energy (SFE) for the treated stainless steel increased measurably compared to the untreated surface. The Ar–O₂ plasma was more effective in enhancing the SFE than Ar-only plasma. Optimum conditions for the plasma treatment system used in this study were obtained. X-ray photoelectron spectroscopy (XPS) characterization of the chemical composition of the treated surfaces confirms the existence of new oxygen-containing functional groups contributing to the change in the hydrophilic nature of the surface. These new functional groups were generated by surface reactions caused by reactive oxidation of substrate species. Atomic force microscopy (AFM) images were generated to investigate morphological and roughness changes on the plasma treated surfaces. The aging effect in air after treatment was also studied.

Keywords: SS 316L; Corona streamer plasma; Contact angle; Surface free energy; Hydrophilicity; XPS and AFM

Uranium (VI) sorption by multiwalled carbon nanotubes from aqueous solution by Ismail I. Fasfous; Jamal N. Dawoud (pp. 433-440).

► Sorption of uranium (VI) onto multiwalled carbon nanotubes. ► The sorption process was well described by pseudo-second-order kinetics. ► Langmuir isotherm was found to best represent the measured sorption data. ► Sorption process was spontaneous and more favorable at higher temperatures.Sorption of uranium (VI) from aqueous solutions onto Multiwalled Carbon Nanotubes (MWCNTs) has been studied under varying experimental conditions of initial uranium concentration, contact time, pH, and temperature, to assess the kinetic and equilibrium parameters. The optimum pH for sorption of uranium (VI) onto MWCNTs was 5. The kinetic data were fitted with pseudo-first-order, pseudo-second-order, and intra-particle diffusion models. The sorption process was well described by pseudo-second-order kinetics. The uranium sorption data were fitted by the Langmuir, Freundlich, and Dubinin–Radushkevich equilibrium models to obtain the characteristic parameters of each model. The Langmuir isotherm was found to best represent the measured sorption data. According to the evaluation using the Langmuir model, the maximum sorption capacity of uranium (VI) ions onto MWCNTs increased with temperature, from 24.9 to 39.1mgg⁻¹ when the temperature was increased from 298 to 318K. The calculated sorption thermodynamic parameters including Δ G°, Δ H°, and Δ S° indicated the spontaneous nature of uranium sorption onto MWCNTs. The results suggest that MWCNTs are suitable materials for preconcentration and solidification of uranium (VI) species from aqueous solutions.

Keywords: Uranium; Carbon nanotubes; Sorption; Equilibrium; Kinetics; Thermodynamics

Decoration of BiOI quantum size nanoparticles with reduced graphene oxide in enhanced visible-light-driven photocatalytic studies by Zhang Liu; Weicheng Xu; Jianzhang Fang; Xiaoxin Xu; Shuxing Wu; Ximiao Zhu; Zehua Chen (pp. 441-447).

Display Omitted► RGO/BiOI nanocomposites were synthesized by a reverse microemulsion method. ► Quantum sized BiOI nanoparticles can be obtained by this approach. ► Ascorbic acid was used as a reducing agent to reduce GO and seemed to be effective. ► RGO/BiOI presented outstanding visible-light-induced photocatalytic performance. ► Possible photocatalytic mechanism was proposed based on the experimental studies.Herein, a reverse microemulsion route was developed to synthesize bismuth oxyiodide (BiOI) nanocrystals and reduced graphene oxide (RGO) nanocomposites as a highly efficient photocatalyst, and both the formation of BiOI and the reduction of RGO were achieved in situ in microemulsions simultaneously at low temperature (60°C). The uniform nanocrystal size and structure were indicated by XRD, TEM, and the reduction of GO by ascorbic acid was evidenced by FTIR, XPS, and Raman spectra techniques. The enhanced photoactivity of RGO/BiOI nanocomposites under visible light was attributed to improved light absorption and efficient charge separation and transportation.

Keywords: Quantum size; BiOI; Reduced graphene oxide; Microemulsion; Visible light

Effects of negative substrate bias voltage on the structure and properties of aluminum oxide films prepared by DC reactive magnetron sputtering by Xiufeng Tang; Fa Luo; Fang Ou; Wancheng Zhou; Dongmei Zhu; Zhibin Huang (pp. 448-453).

► Effects of V_b on as-deposited, annealed and heated Al_xO_y films are studied. ► The crystallization intensity of heated films gets weaker with increasing V_b. ► Grain refinement for as-deposited films and crack surface for annealed are found. ► Films after annealing exhibit higher transmittance but lower microhardness.Aluminum oxide thin films (Al_xO_y) were deposited onto Ni-based superalloy substrates by DC reactive magnetron sputtering using Al target in an Ar and O₂ gas environment. Subsequently post-deposition annealing was carried out in air ambient at 500°C for 1h with heating rate of 25°C/min and then some annealed samples were heated at 800°C for 1h to simulate the application environment. Effects of the negative substrate bias voltage ( V_b) on the structure and properties of the as-deposited, the annealed and the heated films, such as the deposition rate, elemental composition, surface morphology, microstructure, optical transmittance and microhardness, have been studied. It is found that with the increase of negative V_b (0V, −20V, −30V and −40V), the deposition rate decreases sharply and so do the O/Al ratios of the as-deposited films. While for the annealed films, the O/Al ratios show an increasing trend. All the as-deposited and annealed films are amorphous. However, the heated films are all crystallized and the crystallization gets weaker with the negatively increasing V_b. Grain refinement for the as-deposited films and loose crack surface for the annealed ones are found in the process of negatively increasing V_b to −40V. And all the annealed films exhibit higher transmittance but lower microhardness than the as-deposited ones.

Keywords: Aluminum oxide (Al; _x; O; _y; ) film; DC reactive magnetron sputtering; Negative substrate bias voltage (; V; _b; ); Annealing; Heat treatment

Effect of Ar bubbling during plasma electrolytic oxidation of AZ31B magnesium alloy in silicate electrolyte by Junghoon Lee; Yonghwan Kim; Wonsub Chung (pp. 454-459).

► Argon gas was bubbled during PEO of Mg alloy. ► Locally concentrated discharge phenomena were appeared. ► A fraction of Mg₂SiO₄ phase was increased in the inner layer of oxide film. ► Improvement in corrosion resistance was achieved.Argon gas was bubbled during plasma electrolytic oxidation (PEO) treatment of magnesium alloy in a silicate solution. The appearance of arcs and plasma discharging was locally concentrated on the magnesium alloy surface and phase fraction of Mg₂SiO₄ in the oxide layer was increased due to Argon gas bubbling. The higher energy density of the Ar plasma atmosphere is believed to contribute to the effective formation of the high temperature phase (Mg₂SiO₄), particularly in the inner layer. Furthermore, the PEO treated Mg alloy with Ar bubbling showed improved corrosion resistance by a change of open pores structure.

Keywords: Magnesium alloy; Ar gas; Plasma electrolytic oxidation; Corrosion resistance; Mg; ₂; SiO; ₄

Optoelectronic properties of graphene oxide thin film processed by cost-effective route by Farzana A. Chowdhury; Takuya Morisaki; Joe Otsuki; M. Sahabul Alam (pp. 460-464).

Display Omitted► Advantage of a cost-effective mass production of graphene oxide (GO) with less defects. ► Thermal reduction of GO at a temperature as low as 170°C without any reagent. ► Desired optical and electrical properties in a cost effective path to be applicable as a potential candidate for optoelectronic applications.We present large area graphene oxide (GO) thin films as a potential transparent electrode fabricated by using simple route. Atomic force microscopy (AFM) topographies showed a uniform film texture that is wrinkle-free with roughness as low as ∼1.4nm. Desired optical and electrical properties were achieved by thermal reduction at a temperature as low as 170°C without any reagent; which is an important factor in practical application field. Microstructural perfection is quite evident from the abrupt descent around specific energy of photons in the transmittance spectrum. In particular, we explore that device-quality GO thin films can be obtained via a low-cost scalable technique in comparison with other previous works. Urbach energy and different electrical parameters are addressed. The nature and extent of the band gap are analyzed. The findings are very significant in view of an optimized use of GO thin films in electrical and photoelectric applications.

Keywords: Graphene oxide; Thin films; Optoelectronic properties

Solvent-free covalent functionalization of multi-walled carbon nanotubes and nanodiamond with diamines: Looking for cross-linking effects by Elena V. Basiuk; Vladimir A. Basiuk; Víctor Meza-Laguna; Flavio F. Contreras-Torres; Melchor Martínez; Aarón Rojas-Aguilar; Marco Salerno; Guadalupe Zavala; Andrea Falqui; Rosaria Brescia (pp. 465-476).

Display Omitted► Diamines were used for one-step functionalization of nanotubes and nanodiamond. ► We found experimental evidences of cross-linking effects in these nanomaterials. ► We found a strong orientation effect in the functionalized carbon nanotubes.The covalent functionalization of carbon nanomaterials with diamines is a way to enhance the mechanical strength of nanocomposites due to cross-linking effects, to form complex networks for nanotube-based electronic circuits, as well as is important for a number of biomedical applications. The main goal of the present work was to covalently functionalize pristine multi-walled carbon nanotubes and nanodiamond with three aliphatic diamines (1,8-diaminooctane, 1,10-diaminodecane and 1,12-diaminododecane) and one aromatic diamine (1,5-diaminonaphthalene), by employing a simple one-step solvent-free methodology, which is based on thermal instead of chemical activation. We looked for experimental evidences of cross-linking effects in the carbon nanomaterials synthesized by using solubility/dispersibility tests, atomic force microscopy, scanning and transmission electron microscopy, as well as Fourier-transform infrared spectroscopy and thermogravimetric analysis for additional characterization.

Keywords: Multi-walled carbon nanotubes; Nanodiamond; Diamines; Functionalization; Solvent-free; Cross-linking

Structural investigation of nC-Si/SiO_x:H thin films from He diluted (SiH₄+CO₂) plasma at low temperature by Arup Samanta; Debajyoti Das (pp. 477-485).

Display Omitted► nC-Si/SiO_x:H thin films prepared at low temperature He diluted (SiH₄+CO₂) plasma. ► Three layers growth structure identified by FESEM and modeling on ellipsometry data. ► Control of nanocrystallization with simultaneous oxygenation at optimum plasma pressure.Detail structural characterizations of the nC-Si/SiO_x:H films prepared from low temperature (300°C) SiH₄ plasma, have been performed using various spectroscopic and microscopic probes, e.g., IR spectroscopy, ellipsometry, scanning electron microscopy and atomic force microscopy. The growth structure has been probed by Bruggeman effective medium approximation fitting to the ellipsometry data, considering a three-layer growth model, which has been identified by FESEM studies. It has been observed that with the reduction in pressure ( p) the overall crystallinity improves along with the lowering in the incubation layer thickness, and the reduction of void fraction in the bulk as well as in the growth zone and surface layer. The maximum crystallinity in the bulk has been identified at p=0.6Torr, corresponding to the lowest roughness on the surface. Oxygen incorporation has been found to be favored at lower gas pressure in the plasma, along with simultaneous dehydrogenation of the silicon network which remains the key criteria for attaining enhanced nanocrystallinity. Plausible formation mechanism of the nC-Si/SiO_x:H structure, activated by chemical reactions occurring in the He diluted (SiH₄+CO₂) plasma has been investigated.

Keywords: nC-Si/SiO; _x; :H; Growth structure; Ellipsometry; Thin film

Preparation and electromagnetic properties of Polyaniline(polypyrrole)-BaFe₁₂O₁₉/Ni_0.8Zn_0.2Fe₂O₄ ferrite nanocomposites by Yan Wang; Ying Huang; Qiufen Wang; Qian He; Lin Chen (pp. 486-493).

► Synthesizing the polyaniline(PANI)/polypyrrole(PPy)-BaFe₁₂O₁₉/Ni_0.8Zn_0.2Fe₂O₄ composites by in situ polymerization. ► With excellent thermal stability and electromagnetic properties. ► Electrical conductivity and magnetic properties changed with the content of PANI (PPy). ► Potential applications in magnetic recording media and microwave materials.The nanocomposite of hard (BaFe₁₂O₁₉)/soft ferrite (Ni_0.8Zn_0.2 Fe₂O₄) was prepared by the sol–gel process, and then the polyaniline(PANI)/polypyrrole(PPY)-BaFe₁₂O₁₉/Ni_0.8Zn_0.2Fe₂O₄ was produced by in situ polymerization method. The structures, morphology and electromagnetic properties of the samples were characterized by various instruments. XRD, TEM, and FTIR analysis indicated that BaFe₁₂O₁₉/Ni_0.8Zn_0.2Fe₂O₄ ferrite were homogenously enwrapped by PANI(PPY) coating. The VSM and SDY-4 measurement show that the magnetic properties of the composites decreased with the increase in PANI(PPY) amount, However, the electrical conductivity is on the contrary. The electromagnetic properties of the composites were much better than BaFe₁₂O₁₉/Ni_0.8Zn_0.2Fe₂O₄ in the frequency range of 2–15GHz, which mainly depends on the dielectric loss of PANI(PPY). A minimum reflection loss of the PANI(PPY)-BaFe₁₂O₁₉/Ni_0.8Zn_0.2Fe₂O₄ ferrite nanocomposite is −19.7dB(−21.5dB) at the frequency of 7.3GHz (10.7GHz).

Keywords: BaFe; ₁₂; O; ₁₉; Ni; _0.8; Zn; _0.2; Fe; ₂; O; ₄; Polyaniline; Polypyrrole; Electromagnetic properties; In situ polymerization

Surface modification of polyimide (PI) film using water cathode atmospheric pressure glow discharge plasma by Peichao Zheng; Keming Liu; Jinmei Wang; Yu Dai; Bin Yu; Xianju Zhou; Honggang Hao; Yuan Luo (pp. 494-500).

► Equipment called water cathode atmospheric pressure glow discharge was used to improve the hydrophilicity of polyimide films. ► The data shows good homogeneity and the variation trends of contact angles are different for polar and non-polar testing liquids. ► The thickness of liquid layer plays an important role in plasma processing and directly affects the treatment effect. ► Surface hydrophilicity after plasma treatment is improved partly due to the increase in the roughness. ► The hydrophilicity of polyimide films is still better than untreated ones after long-term storage.The industrial use of polyimide film is limited because of undesirable properties such as poor wettability. In the present paper, a new kind of equipment called water cathode atmospheric pressure glow discharge was used to improve the surface properties of polyimide films and made them useful to technical applications. The changes in hydrophilicity of modified polyimide film surfaces were investigated by contact angle, surface energy and water content measurements as a function of treatment time. The results obtained show good treatment homogeneity and that the variation trends of contact angles are different for polar and non-polar testing liquids, while surface energy and water content are significantly enhanced with the increase of treatment time until they achieve saturated values after 60s plasma treatment. Also, the thickness of liquid layer plays an important role in plasma processing and directly affects the treatment effect. Changes in morphology of polyimide films were analyzed by atomic force microscope and the results indicate that surface hydrophilicity after plasma treatment are improved partly due to the increase in the roughness. In addition, polyimide films treated by plasma are subjected to an ageing process to determine the durability of plasma treatment. It is found that the hydrophilicity is still better than untreated ones though the hydrophobic character partly recovers after long-term storage in ambient air.

Keywords: Polyimide (PI); Atmospheric pressure; Glow discharge; Hydrophilicity; Contact angle; Surface energy

Ultrasound assisted deposition of silica coatings on titanium by Recep Kaş; Fatma Sinem Ertaş; Özgür Birer (pp. 501-507).

Display Omitted► Coatings are formed in solution by deposition of multiple layers of silica particles. ► Silica particles are pushed to an activated surface by ultrasound induced cavitations. ► Coating thickness can be controlled by reaction parameters.We present a novel ultrasound assisted method for silica coating of titanium surfaces. The coatings are formed by “smashing” silica nanoparticles onto activated titanium surface in solution using intense ultrasonic field. Homogeneous silica coatings are formed by deposition of dense multiple layers of silica nanoparticles. Since the nanoparticles also grow during the reaction, the layers of the coatings have smaller particles on the substrate and larger particles towards the surface. The thickness of the coatings can be controlled with several experimental parameters. Silica layers with thickness over 200nm are readily obtained.

Keywords: Silica coatings; Ultrasound; Surface modification

Microstructural characterization and mechanical properties of nitrided layers on aluminum substrate prepared by nitrogen arc by Xiaoyi Zheng; Zhenan Ren; Xin Li; Yanan Wang (pp. 508-514).

► The composite nitrided layer on aluminum substrate is prepared by the nitrogen arc. ► The nitrided layer consists of the aluminum nitride and aluminum solid solution. ► The nitrided layer exhibits two morphologies of dendrites and lamellae. ► The hardness and wear resistance increased with increasing of N₂/Ar ratio.The present work explores the feasibility of nitrided layers prepared on the aluminum substrate by nitrogen arc discharge at atmospheric pressure. The composite nitrided layers consisted of AlN and aluminum solid solution phases were obtained by the nitrogen arc discharge at the different nitrogen to argon gas flow ratios. The effect of the nitrogen gas contents in the gas mixture on microstructures, hardness and wear resistance of the nitrided layers was investigated. There were lamellar microstructures of AlN and aluminum solid solution distributed alternately at the upper portion of the nitrided layer and the AlN dendrites mainly distributed at the middle and bottom of the layer. It was found that the nitrided layers had high hardness, good wear resistance. With increasing the nitrogen to argon gas flow ratios, the thickness, hardness and wear resistance of the layers were enhanced significantly.

Keywords: Nitrogen arc; Aluminum nitride; Dendrite; Lamellar; Hardness; Wear resistance

Dropwise condensation rate of water breath figures on polymer surfaces having similar surface free energies by Ikrime O. Ucar; H. Yildirim Erbil (pp. 515-523).

Display Omitted► Formation and growth of breath figures in the first regime were investigated. ► Polyolefin surfaces having close surface tension but different CAH were used. ► Roughness and CAH has an important effect on nucleation and condensation rate. ► The number density of droplets increased mainly with the increase in roughness. ► Droplet surface coverage increased with the increase in roughness and CAH.This study investigates the effect of surface roughness, wettability, water contact angle hysteresis ( CAH) and wetting hysteresis ( WH) of polymeric substrates to the water drop condensation rate. We used five polyolefin coatings whose surface free energies were in a close range of 30–37mJ/m² but having different surface roughness and CAH. The formation of water breath figures was monitored at a temperature just below the dew point. The initial number of the condensed droplets per unit area ( N₀) and droplet surface coverage were determined during the early stage of drop condensation where the droplet coalescence was negligible. It was found that the mean drop diameter of condensed droplets on these polymer surfaces grow according to a power law with exponent 1/3 of time, similar to the previous reports given in the literature. It was determined that surface roughness and corresponding CAH and WH properties of polymers have important effects on the number of nucleation sites and growth rate of the condensed water droplets. N₀ values and the surface coverage increased with the increase in surface roughness, CAH and WH of the polymer surfaces. The total condensed water drop volume also increased with the increase in surface roughness in accordance with the increase of the number of nucleated droplets.

Keywords: Dropwise condensation; Contact angle hysteresis; Surface coverage; Roughness; Polyolefin

Influence of Li-doping on structural characteristics and photocatalytic activity of ZnO nano-powder formed in a novel solution pyro-hydrolysis route by Ibram Ganesh; P.S. Chandra Sekhar; G. Padmanabham; G. Sundararajan (pp. 524-537).

► Li-doping improves the photocatalytic ability of ZnO. ► The reactivation of the deactivated ZnO catalyst can be achieved by washing with H₂O. ► 10wt.% Li-doped ZnO completely decomposes 1mM methylene blue solution in 40min. ► A simple solution pyro-hydrolysis technique can be employed to synthesize nano-sized ZnO powders. ► Li and Al co-doped ZnO follows first order kinetics in methylene blue degradation reaction.Different types of Li-doped ZnO (LDZ) (Li=0–10wt.%) powders were prepared by following a novel pyro-hydrolysis route at 450°C, and were thoroughly characterized by means of thermo-gravimetry (TG), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared (FT-IR), Fourier-transform Raman (FT-Raman) spectroscopy, diffuse reflectance spectroscopy (DRS), ultra-violet visible (UV–Vis) spectroscopy, Brunauer–Emmett–Teller (BET) surface area (SA), and zeta potential ( ζ) measurements. Photocatalytic activity of these powders was evaluated by means of methylene blue (MB) degradation experiments conducted under the irradiation of simulated and natural solar light. Characterization results suggest that both pure ZnO and LDZ powders are quite thermally stable up to a temperature of 700°C and possess band gap (BG) energies in the range of 3.16–3.2eV with a direct band to band transition and ζ values of −31.6mV to −56.4mV. The properties exhibited by LDZ powders were found to be quite comparable to those exhibited by p-type semi-conducting LDZ powders. In order to study the kinetics of MB degradation reaction under the irradiation of simulated solar light, the Li (0.2–10wt.%) and Al (0.5wt.%) co-doped ZnO (0.2LADZ to 10LADZ) powders were also synthesized and employed for this purpose. The photocatalytic degradation of MB over LADZ catalysts followed the Langmuir–Hinshelwood (L–H) first order reaction rate relationship. The 10LDZ catalyst exhibited highest photocatalytic activity among various powders investigated in this study.

Keywords: ZnO; Li-doped ZnO; Photocatalysis; Methylene blue degradation; Band gap energy

Stability of FDTS monolayer coating on aluminum injection molding tools by Jiri Cech; Rafael Taboryski (pp. 538-541).

► We present novel and highly useful results on FDTS monolayer coating of aluminum. ► The coating is particularly applicable for coating of prototyping injection molding tools, which often are made of Al. ► We have demonstrated that the coating prevails in injection molding conditions and that the coating will prevent wear of the tools.We have characterized perfluorodecyltrichlorosilane (FDTS) molecular coating of aluminum molds for polymer replication via injection molding (IM). X-ray photoelectron spectroscopy (XPS) data, sessile drop contact angles with multiple fluids, surface energies and roughness data have been collected. Samples have been characterized immediately after coating, after more than 500 IM cycles to test durability, and after 7 months to test temporal stability. The coating was deposited in an affordable process, involving near room temperature gas phase reactions. XPS shows detectable fluorine presence on both freshly coated samples as well as on post-IM samples with estimated 30at.% on freshly coated and 28at.% on post-IM samples with more than 500 IM cycles with polystyrene (PS) and ABS polymer.

Keywords: FDTS coating; Aluminum injection molding tools; XPS; Contact angle

Self-supporting superhydrophobic thin polymer sheets that mimic the nature's petal effect by Mustafa Karaman; Nihat Çabuk; Demet Özyurt; Özcan Köysüren (pp. 542-546).

► Polymeric thin films were deposited by initiated CVD method on a biological template. ► Conformal nature of iCVD helps to make exact copies of natural surfaces. ► Biomimetic polymer sheet has the same wetting characteristics of the rose surface.The high adhesive force between the red rose petal and the water droplet on its surface is termed as the ‘petal effect’, which is caused by the hierarchical array of micro papilla on the surfaces together with the nano-folds existing on top of each papilla. Because of that special surface topography, the surface is superhydrophobic, but at the same time highly adherent to the water droplet such that the droplet cannot move even if the surface is turned upside down. In this work, we produced a thin (thickness below 1μm) self-supporting polymer sheet that mimics the surface of a red rose petal. The product is a two-layer polymer sheet made from poly(glycidyl methacrylate) (PGMA) as the supporting layer and a hydrophobic poly(1H,1H,2H,2H-perfluorodecyl acrylate) (PPFDA) on top of it as the functional layer, both of which were deposited by initiated chemical vapor deposition (iCVD) process. The integration of conformal and solvent-free iCVD process into the classical two-step molding procedure allowed exact transfer of surface topography of the petal surface, which was verified by SEM analysis. The static contact angle of water droplet on the surface of the polymer replica was found to be 152±3°, and the water droplet did not roll-off even the polymer sheet is tilted or turned upside down.

Keywords: Petal effect; iCVD; Biomimetics; Bioreplication; Contact angle

Mixed matrix membranes with HF acid etched ZSM-5 for ethanol/water separation: Preparation and pervaporation performance by Xia Zhan; Juan Lu; Tingting Tan; Jiding Li (pp. 547-556).

.Display Omitted► MMMs were prepared by incorporation of surface etched ZSM-5 with HF acid into PDMS membranes. ► Effect of the zeolite surface morphology on interfacial integration and pervaporation performance of ZSM-5/PDMS MMMs. ► The pervaporation mechanism of MMMs was investigated based on sorption experiment. ► MMMs filled with etched ZSM-5 showed much better separation performance than that filled with non-etched ones.The mixed matrix membranes (MMMs) were prepared from crosslinked PDMS incorporated with HF acid etched ZSM-5. ZSM-5 zeolite was etched with a series of HF aqueous-acetone solution and characterized by SEM, BET, XRD and FT-IR. It was found that HF etching process was very effective for removing organic impurities in zeolite and micro-pores were observed out of the surface of zeolite particles, which enhanced the hydrophobicity and surface roughness of ZSM-5 successfully. Both tensile strength and swelling resistance of ZSM-5/PDMS MMMs increased with the rising concentration of HF solution, which can mainly be attributed to the improved zeolite-PDMS interfacial adhesion resulted from the intrusion of PDMS into micro-pores out of the ZSM-5 surface. Subsequently, the sorption experiment was performed with the results suggesting preferential sorption of ethanol by MMMs. Moreover, the sorption selectivity of ZSM-5/PDMS MMMs increased notably as the concentration of HF solution increased. The pervaporation performance of ethanol/water mixtures using MMMs was also investigated in detail. The MMMs filled with etched ZSM-5 showed much better selectivity than that filled with non-etched ones, with a little expense of permeability. It was found that with the same zeolite loading, increasing the HF acid concentration in etching process enhanced the zeolite-PDMS interfacial adhesion which promoted the ethanol selectivity of MMMs, while depressed the total permeation flux a little. In addition, both ethanol permeation and the selectivity increased with an increase of the zeolite loading from 10% to 30%. Nevertheless, excessive zeolite loading or decreasing thickness of selective layer led to the poor selectivity to ethanol. A decline of the ethanol selectivity was also observed as the feed ethanol concentration as well as feed temperature increased.

Keywords: HF acid; Etching; ZSM-5/PDMS; MMMs; Ethanol/water; Pervaporation

Photocatalytic properties of hierarchical ZnO flowers synthesized by a sucrose-assisted hydrothermal method by Wei Lv; Bo Wei; Lingling Xu; Yan Zhao; Hong Gao; Jia Liu (pp. 557-561).

► Hierarchical ZnO flowers were synthesized via a sucrose-assisted urea hydrothermal method. ► The sucrose added ZnO flowers showed improved activity mainly due to the improved crystallinity. ► The effect of sucrose content was studied and optimized.In this work, hierarchical ZnO flowers were synthesized via a sucrose-assisted urea hydrothermal method. The thermogravimetric analysis/differential thermal analysis (TGA–DTA) and Fourier transform infrared spectra (FTIR) showed that sucrose acted as a complexing agent in the synthesis process and assisted combustion during annealing. Photocatalytic activity was evaluated using the degradation of organic dye methyl orange. The sucrose added ZnO flowers showed improved activity, which was mainly attributed to the better crystallinity as confirmed by X-ray photoelectron spectroscopy (XPS) analysis. The effect of sucrose amount on photocatalytic activity was also studied.

Keywords: ZnO flowers; Photocatalytic properties; Hydrothermal method; Sucrose

Optimal Zn/O ratio in vapor phase for the synthesis of high quality ZnO tetrapod nanocrystals via thermal evaporation of Zn in Air by Geun-Hyoung Lee (pp. 562-565).

► Tetrapod ZnO nanocrystals were synthesized through thermal evaporation of Zn in air. ► There is an optimal Zn/O ratio required for the synthesis of tetrapod ZnO nanocrystals. ► Zn/O ratio in vapor phase had an effect on the optical properties of tetrapod ZnO nanocrystals.Tetrapod-shaped ZnO nanocrystals were synthezised via thermal evaporation of Zn powder in air. The Zn powder was oxidized at 930°C for 60min. To investigate the optimal Zn/O molar ratio in such vapor phase synthesis, the Zn content was varied in range of 0.1–0.75g. When the Zn content was 0.1g, no nanocrystals were formed. Above 0.25g Zn, growth of ZnO nanocrystals started without clear tetrapod like morphology. Beyond Zn content of 0.50g, clear tetrapod-shaped ZnO nanocrystals were detected. These results establish that there is a certain required ratio of zinc and oxygen in vapor phase for generation of tetrapod-shaped ZnO nanocrystals. Such Zn:O ratio is also calculated theoretically from the ideal gas law. Clear tetrapod type ZnO nanocrystals prepared with Zn content of 0.5g exhibited the highest intensity of the ultraviolet emission centered at 380nm which also confirms the high crystalline quality of such ZnO nanocrystals.

Keywords: ZnO tetrapod; Zn powder; Thermal evaporation; Air atmosphere; Zn/O ratio

One-pot hydrothermal synthesis of a mesoporous SiO₂–graphene hybrid with tunable surface area and pore size by Xun Zhou; Tiejun Shi (pp. 566-573).

► A one-pot hydrothermal synthesis was used to prepare a mesoporous SiO₂-graphene hybrid from tetraethyl ortho silicate (TEOS) and graphene oxide (GO) without any surfactant. ► The synthesis technique combines protection, reduction and functionalization in one step. ► Nitrogen adsorption/desorption isotherms showed that the hybrid was tunable in surface area, pore size and its distribution by simple adjustment of the mass ratio of TEOS and GO.A one-pot hydrothermal synthesis was used to obtain a mesoporous SiO₂–graphene hybrid from tetraethylortho silicate and graphene oxide without any surfactant. Graphene obtained from hydrothermal reduction, with a certain oxygen-containing groups, plays a key role in attaching SiO₂ nanoparticles, as examined by X-ray diffraction, Raman spectroscopy, transmission electron microscopy and scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and atomic force microscopy. The synthesis technique combines protection, reduction and functionalization in one step. Nitrogen adsorption/desorption isotherms showed that the hybrid was tunable in surface area (244.7–524.61m²/g), pore size (8.9–69.26nm) and its distribution by simple adjustment of the mass ratio of tetraethylortho silicate and graphene oxide.

Keywords: Mesoporous; SiO; ₂; –graphene hybrid; Hydrothermal synthesis; Tunable

Size characterisation of noble-metal nano-crystals formed in sapphire by ion irradiation and subsequent thermal annealing by Pablo-Ernesto Mota-Santiago; Alejandro Crespo-Sosa; José-Luis Jiménez-Hernández; Hector-Gabriel Silva-Pereyra; Jorge-Alejandro Reyes-Esqueda; Alicia Oliver (pp. 574-581).

Display Omitted► Systematic study on the formation of Ag and Au nano-particles in Al₂O₃. ► Annealing in a reducing atmosphere, below the metal melting point is more suitable. ► Au nano-particles grow up to 15nm and Ag nano-particles up to 45nm in radius. ► Ostwald ripening is the mechanism responsible for the formation of large nanoparticles. ► Optical properties of metallic nano-particles in Al₂O₃ can be related to their size.Metallic nano-particles embedded in transparent dielectrics are very important for new technological applications because of their unique optical properties. These properties depend strongly on the size and shape of the nano-particles. In order to achieve the synthesis of metallic nano-particles it has been used the technique of ion implantation. This is a very common technique because it allows the control of the depth and concentration of the metallic ions inside the sample, limited mostly by straggling, without introducing other contaminant agents. The purpose of this work was to measure the size of the nano-particles grown under different conditions in Sapphire and its size evolution during the growth process. To achieve this goal, α-Al₂O₃ single crystals were implanted with Ag or Au ions at room temperature with different fluences (from 2×10¹⁶ions/cm² to 8×10¹⁶ions/cm²). Afterwards, the samples were annealed at different temperatures (from 600°C to 1100°C) in oxidising, reducing, Ar or N₂ atmospheres. We measured the ion depth profile by Rutherford Backscattering Spectroscopy (RBS) and the nano-crystals size distribution by using two methods, the surface plasmon resonance in the optical extinction spectrum and the Transmission Electron Microscopy (TEM).

Keywords: Nucleation; Ostwald ripening; Ion implantation; Nano-composites

Reactive sputtering of ZnO:Al thin films from rotatable dual metallic targets by H. Zhu; J. Hüpkes; E. Bunte; S.M. Huang (pp. 582-589).

► ZnO:Al films are prepared by reactively sputtering from rotatable dual metallic targets. ► High rate ZnO:Al films with good electrical and optical properties as well as proper surface structures are achieved at the transition mode region. ► Different working points or PEM intensities lead to different deposition rates, which are related with oxygen partial pressure as well as the sputtering properties to oxide and metal materials. ► The oxygen partial pressure plays a important role on different properties of reactively sputtered ZnO:Al films.In this study, aluminum doped zinc oxide (ZnO:Al) films were prepared by reactively sputtering from rotatable dual metallic targets, which were controlled by a plasma emission monitoring (PEM) system. The influences of different sputtering conditions including different discharge powers, working pressures and working points (or oxygen partial pressure) on ZnO:Al films are investigated systematically. It is found that the deposition rate strongly relies on the discharge power. However, different PEM intensities lead to different deposition rates, which are related with oxygen partial pressure as well as the sputtering properties to oxide (ZnO) and metal (zinc) materials. In addition, the oxygen partial pressure at different PEM intensities strongly influences the electrical and optical properties as well as morphologies and etching behaviors of ZnO:Al films. High rate ZnO:Al films with good electrical and optical properties as well as proper surface structures are achieved at the transition mode region. High deposition rate of up to 100nmm/min and high carrier mobility of up to 41cm²/Vs are achieved, which demonstrates the great advantage for such a cost-efficient sputtering technique. The surface structure of high rate ZnO:Al films can be modified further by etching with a novel two-step etching method and good device performance has been achieved when they applied in silicon thin film solar cells.

Keywords: ZnO:Al thin film; Reactive sputtering; PEM intensity; Oxygen partial pressure

Electron backscatter diffraction analysis of ZnO:Al thin films by C.B. Garcia; E. Ariza; C.J. Tavares; P. Villechaise (pp. 590-595).

► Microstructure and crystallographic aspects of ZnO:Al thin films were investigated by EBSD. ► Both top surface and cross-section analysis were performed. ► Strong texture on the basal plane orientation was observed on the analyzed thin film surface. ► A strong prismatic texture was found in cross-section analysis.Microstructural characterization and crystallographic orientation aspects of aluminium doped zinc oxide (ZnO:Al) thin films have been investigated by means of electron backscatter diffraction. ZnO:Al was produced by magnetron sputtering deposition from a ZnO ceramic target containing 2.0wt% Al₂O₃ and 0.12wt% Y₂O₃. Both top surface and cross-section analysis were performed. The experimental details concerning specific sample preparation procedures for EBSD investigations are presented. Crystalline texture was described by the inverse pole figure (IPF) maps. Strong texture on the basal plane orientation was observed on the analyzed thin film surface. In accordance with these results obtained from top surface investigations, a strong prismatic texture was found in cross-section analysis. From all these analyses a good description and quantification of the three dimensional configuration of the grains and of their crystallographic texture can be proposed.

Keywords: EBSD; ZnO:Al; Sputtering; Microstructure characterization

Effect of deposition temperature on the properties of Al-doped ZnO films prepared by pulsed DC magnetron sputtering for transparent electrodes in thin-film solar cells by Doo-Soo Kim; Ji-Hyeon Park; Beom-Ki Shin; Kyeong-Ju Moon; Myoungwoo Son; Moon-Ho Ham; Woong Lee; Jae-Min Myoung (pp. 596-599).

► Surface-textured AZO films were achieved by combining PDMS method with wet etching. ► The AZO film deposited at 230°C by PDMS exhibited the best performance. ► It is due to the higher plasma density supplied from PDMS system. ► Wet etching of the films produces a crater-like rough surface morphology.A simple but scalable approach to the production of surface-textured Al-doped ZnO(AZO) films for low-cost transparent electrode applications in thin-film solar cells is introduced in this study by combining pulsed dc magnetron sputtering (PDMS) with wet etching in sequence. First, structural, electrical, and optical properties of the AZO films prepared by a PDMS were investigated as functions of deposition temperature to obtain transparent electrode films that can be used as indium-free alternative to ITO electrodes. Increase in the deposition temperature to 230°C accompanied the improvement in crystalline quality and doping efficiency, which enabled the lowest electrical resistivity of 4.16×10⁻⁴Ωcm with the carrier concentration of 1.65×10²¹cm⁻³ and Hall mobility of 11.3cm²/Vs. The wet etching of the films in a diluted HCl solution resulted in surface roughening via the formation of crater-like structures without significant degradation in the electrical properties, which is responsible for the enhanced light scattering capability required for anti-reflective electrodes in thin film solar cells.

Keywords: Al-doped ZnO (AZO); Surface texturing; Transparent conductive oxide; Pulsed dc magnetron sputtering

Enhancement of photovoltaic characteristics of nanocrystalline 2,3-naphthalocyanine thin film-based organic devices by A.A.M. Farag; W.G. Osiris; A.H. Ammar (pp. 600-609).

Scanning electron microscopy (SEM) image of NPC films: (a) cross section view, (b) surface morphology of the film at 300K, (c) surface morphology of the annealed film at 350K, (d) surface morphology of the annealed film at 400K, (e) surface morphology of the annealed film at 450K, and (f) surface morphology of the annealed film at 500K.Display Omitted► The absorption edge shifts to the lower energy for the annealed NPC film. ► The device of Au/NPC/ITO exhibit rectifying characteristics. ► The devices show improvement in photovoltaic parameters. ► The power conversion efficiency of the devices show enhancement under annealing.In this work, nanocrystalline thin films of 2,3-naphthalocyanine (NPC) were successfully deposited by a thermal evaporation technique at room temperature under high vacuum (∼10⁻⁴Pa). The crystal structure and surface morphology were measured using X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. A preferred orientation along the (001) direction was observed in all the studied films and the average crystallite size was calculated. Scanning electron miscroscopy (SEM) images of NPC films at different thermal treatment indicated significant changes on surface level patterns and gave clear evidence of agglomeration of nanocrystalline structures. The molecular structural properties of the thin films were characterized using Fourier transform infrared spectroscopy (FTIR), which revealed the stability of the chemical bonds of the compound under thermal treatment. The dark electrical conductivity of the films at various heat treatment stages showed that NPC films have a better conductivity than that of its earlier reported naphthalocyanine films and the activation energy was found to decrease with annealing temperature. The absorption edge shifted to the lower energy as a consequence of the thermal annealing of the film and the fundamental absorption edges correspond to a direct energy gap. The temperature coefficient of the onset and optical band gaps for the film was calculated to be −4.4×10⁻⁴ and −1.76×10⁻³eV/K, respectively. The effect of thermal annealing on the photovoltaic properties of Al/NPC/ITO devices was also considered. The as-deposited device showed maximum power conversion efficiency about 0.70% under illumination of 100mW/cm², whereas 2.65% power conversion efficiency was achieved after annealing the samples at 500K for 1h.

Keywords: Al/NPC/ITO device; Optical band gap; Activation energy; Thermal annealing; Nanostructured film

A new ion exchange behavior of protonated titanate nanotubes after deprotonation and the study on their morphology and optical properties by Huibin Zhang; Lixin Cao; Wei Liu; Ge Su (pp. 610-615).

The morphological transformation of protonated titanate nanotubes under alkali solution before ion exchange (a) and after ion exchange (b).Display Omitted► A novel ion exchange behavior of protonated titanate nanotubes after deprotonation. ► The exchangeability of protonated titanate nanotubes are not as inert as past reported. ► The tube walls of H₂Ti₃O₇ nanotubes is observed to get loosened after ion exchange. ► The paper proves a new and easy way to modify protonated titanate nanotubes.After the deprotonation of protonated titanate nanotubes (H₂Ti₃O₇), we observed a novel ion exchange behavior on them. In the past literatures, protonated titanate nanotubes prepared via hydrothermal method have been reported with a poor exchangeability which may due to the chemical bonding of interlayer protons to nearby oxygen atoms. However, in this experiment under alkali environment (pH>10), protonated titanate nanotubes exhibited a vast ion exchange capacity toward [Co(NH₃)₆]²⁺. This interesting phenomenon is contrary to the past reports which found protonated titanate nanotubes hardly could be ionexchanged by objective cations. This paper proves the deprotonation process on H₂Ti₃O₇ nanotubes sufficiently facilitates the diffusion of metal complex cations into protonated titanate nanotubes and significantly changes their ion exchange capacity. As a consequence of cabalt intercalting via ion exchange, the tube wall of H₂Ti₃O₇ nanotubes is observed to get loosened. Additionally, the exciton concentrations corresponding to the nanotube surface states are discussed in the paper.

Keywords: Protonated titanate nanotubes; Ion exchange; Morphology; TiO; ₂; Exciton

Friction and wear properties of Ti6Al4V/WC-Co in cold atmospheric plasma jet by Wenji Xu; Xin Liu; Jinlong Song; Libo Wu; Jing Sun (pp. 616-623).

Display Omitted► Cold plasma jet can effectively reduce the friction coefficients of Ti6Al4V/WC-Co friction pairs. ► Cold plasma jet can easily form nitrides on the surface of Ti6Al4V and on new surfaces generated by tool wear. ► The nitrides can reduce the friction coefficients and protect the friction surface.The friction and wear properties of Ti6Al4V/WC-Co friction pair were studied using an autonomous atmospheric pressure bare electrode cold plasma jet generating device and block-on-ring friction/wear tester, respectively. The study was conducted under air, air jet, nitrogen jet, air cold plasma jet, and nitrogen cold plasma jet atmospheres. Both nitrogen cold and air cold plasma jets effectively reduced the friction coefficients of the friction pairs and decreased friction temperature. The friction coefficient in the nitrogen cold plasma jet decreased to almost 60% compared with that in the air. The scanning electron microscope, energy-dispersive X-ray spectroscope, and X-ray diffraction analyses illustrated that adhesive wear was relieved and the friction surfaces of Ti6Al4V were smoother, both in the nitrogen cold and air cold plasma jets. The roughness value R_a of the Ti6Al4V friction surfaces can reach 1.107μm. A large number of nitrogen particles in the ionic and excited states contained by cold plasma jets reacts easily on the friction surface to produce a large amount of nitrides, which can excellently reduce the wear of Ti6Al4V/WC-Co friction pairs in real-time.

Keywords: Friction; Wear; Cold plasma jet; Ti6Al4V; Nitrogen

Effect of reaction time on the synthesis and electrochemical properties of Mn₃O₄ nanoparticles by microwave assisted reflux method by K. Vijaya Sankar; S.T. Senthilkumar; L. John Berchmans; C. Sanjeeviraja; R. Kalai Selvan (pp. 624-630).

Display Omitted► Mn₃O₄ nanoparticles were prepared using microwave assisted reflux synthesis method at different time periods. ► The maximum specific capacitance of 135Fg⁻¹ at scan rate of 2mVs⁻¹. ► Dislocation density felicitate to the ionic conductivity. ► The enhancing capacitance due to phase or morphological changes in electrode.Spherical Mn₃O₄ nanoparticles were synthesized by microwave assisted reflux method at different reaction times (1, 5, 10, 15, and 20min). The single phase formation of Mn₃O₄ nanoparticles was identified through XRD analysis. The FT-IR and Raman spectra revealed the presence of functional groups of Mn₃O₄ and further support the XRD results. The spherical morphology of Mn₃O₄ was identified via SEM analysis. The cyclic voltammetry analysis implies that 15min synthesized Mn₃O₄ (MN-15) shows the higher specific capacitance of 135Fg⁻¹ among all the prepared Mn₃O₄ electrodes. The EIS spectra of MN-15 substantiate the less charge-transfer resistance ( R_ct) of 0.553Ω, when compared with the other samples. The discharge capacitance of MN-15 was 103Fg⁻¹ at 0.5mAcm⁻² in 1M NaNO₃ solution. The cycling stability curve over 100 cycles implies that the discharge capacitance is increased from 47 to 68Fg⁻¹ at 5mAcm⁻². This capacitance enhancement during cycling is due to the influence of phase or morphological variation of Mn₃O₄ electrodes.

Keywords: Microwave assisted reflux synthesis; Reaction time; Dislocation density; Active site; Energy density; Supercapacitor

Quantum chemical study of fluorinated AlN nano-cage by Javad Beheshtian; Ali Ahmadi Peyghan; Zargham Bagheri (pp. 631-636).

► Adsorption of 1, 2, 3, and 12 F atom(s) on the Al₁₂N₁₂ cluster studied by DFT. ► F atom strongly prefers to be adsorbed on Al site of the cluster rather than N one. ► Average Δ G is about −93.2 to 98.0kcal/mol at 298K and 1atm. ► Δ H of reaction is slightly increased by increasing the number of F atoms. ► The cluster it is transferred from intrinsic semiconductor to p-type one.Adsorption of 1, 2, 3, and 12 F atom(s) on the surface of Al₁₂N₁₂ nanocluster has been investigated using density functional theory. It has been found that the F atom strongly prefers to be adsorbed on Al site of the cluster rather than N one with the average Gibbs free energy change of −93.2 to 98.0kcal/mol at 298K and 1atm. Average enthalpy change of the reaction is slightly increased by increasing the number of F atoms. The F adsorption considerably influences electronic properties of the cluster so that it is transferred from intrinsic semiconductor to p-type one. HOMO/LUMO energy gap of the cluster is narrowed and the Fermi level is dramatically shifted from −4.50eV in the bare cluster to lower energies upon the F adsorptions along with increased work function of the cluster. This results in raised potential barrier of the electron emission for the cluster and hence hindering its field emission. Moreover, it has been shown that the following reaction may occur spontaneously at room temperature and 1atm: Al₁₂N₁₂+6F₂→Al₁₂N₁₂F₁₂.

Keywords: Semiconductors; Aluminum nitride nanocluster; Ab initio; Electronic properties

A first-principles study of the SCN⁻ chemisorption on the surface of AlN, AlP, and BP nanotubes by Alireza Soltani; Mohammad Ramezani Taghartapeh; Hossein Mighani; Amin Allah Pahlevani; Reza Mashkoor (pp. 637-642).

Adsorption properties of SCN⁻ on AlN, AlP, and BP nanotubes based on density functional theory. ▶ We demonstrate the most stable configurations (N-side) of SCN⁻ on AlN, AlP, and BP nanotubes models.Display Omitted► The SCN⁻ Adsorption on surface of AlN, AlP, and BP nanotubes were studied via density functional theory (DFT). ► The interaction of SCN⁻ on the electronic properties and the NBO charge distribution of mentioned configurations are investigated. ► The studies suggest that the adsorption energies of SCN⁻ on AlPNT is most notable in comparison with AlNNT and BPNT.We have performed first-principles calculations to explore the adsorption behavior of the SCN⁻ on electronic properties of AlN, AlP, and BP nanotubes. The adsorption value of SCN⁻ for the most stable formation on the AlPNT is about −318.16kJmol⁻¹, which is reason via the chemisorptions of SCN anion. The computed density of states (DOS) indicates that a notable orbital hybridization take place between SCN⁻ and AlP nanotube in adsorption process. Finally, the AlP nanotube can be used to design as useful sensor for nanodevice applications.

Keywords: Aluminum nitride nanotubes; Aluminum phosphide nanotubes; Boron phosphide nanotubes; SCN; ⁻; DFT

Hydrothermal fabrication of hydroxyapatite on the PEG-grafted surface of wood from Chinese Glossy Privet by Ning Wang; Chuanjie Cai; Dongqing Cai; Junjie Cheng; Shengli Li; Zhengyan Wu (pp. 643-649).

► Polyethylene glycol (PEG) was grafted on Chinese Glossy Privet (CGP) wood surface. ► Hydrated calcium hydrogen phosphate (HCHP) was deposited on the PEG-wood surface. ► The HCHP was transformed into hydroxyapatite by hydrothermal treatment. ► The resulted hydroxyapatite-wood could be a promising bone-repairing material.Wood-hydroxyapatite composite material was developed by depositing hydrated calcium hydrogen phosphate (HCHP) on the surface of wood from Chinese Glossy Privet (CGP) with polyethylene glycol (PEG, HO(CH₂CH₂O)_nH) as the grafting agent and subsequent hydrothermal vapor treatment. The results illustrated that HCHP could adhere quickly and strongly on the PEG-grafted wood surface. Moreover, this HCHP could be efficiently transformed to hydroxyapatite (HA, Ca₁₀(PO₄)₆(OH)₂) by hydrothermal vapor treatment. IR, XRD analysis and SEM observation indicated that the fabricated hydroxyapatite was pure and its morphology was uniform and microporous. This work provides a new fabricating approach of biocompatible material which may have some potential applications as bone-repairing material.

Keywords: Wood; Hydroxyapatite; Composite materials; Polyethylene glycol; Hydrothermal vapor treatment

Adsorption study of anionic reactive dye from aqueous solution to Mg–Fe–CO₃ layered double hydroxide (LDH) by I.M. Ahmed; M.S. Gasser (pp. 650-656).

Second order kinetic model for adsorption of congo red onto Mg–Fe–LDH.Display Omitted► Mg–Fe–CO₃–LDH was utilized as an adsorbent. ► It was used for the removal of congo red (CR), an anionic dye from aqueous solution. ► The adsorption of (CR) is endothermic. ► The adsorption equilibrium was well described by the Langmuir isotherm model. ► Adsorption kinetics of (CR) was found to conform to pseudo-second order model.Mg–Fe–Cl Layered double hydroxides (LDHs) have been prepared using a method involving separate nucleation and aging steps with Mg/Fe=3. The interlayer anions readily replaced by carbonate are characterized by X-ray diffraction (XRD) and FTIR. The effects of different parameters, such as pH, contact time, concentration of dye and temperature on the capacity and adsorption mechanism of Mg–Fe–CO₃–LDH in removing an anionic dye (congo red, CR) from aqueous solution were separately investigated. The results show that Mg–Fe–CO₃–LDH is particularly efficient in removing CR and the dye removal increases with decreasing pH. The adsorption of CR on Mg–Fe–CO₃–LDH reached equilibrium after 15min where 100mg/L CR was removed. The equilibrium isotherm indicates that the adsorption of CR onto Mg–Fe–CO₃–LDH fits to Langmuir and Freundlich equation as well. The adsorption data obtained from the Langmuir model gave good values of the determination coefficient and the saturated adsorption capacity of Mg–Fe–CO₃–LDH for CR was found to be 104.6mg/g. The regeneration study indicates that the prepared LDH could be used for several cycles. The thermodynamic parameters have been calculated, and the adsorption process was found to be spontaneous, endothermic in nature and follows a pseudo-second-order kinetic model.

Keywords: Mg–Fe–LDH; Congo red (CR); Dye; Adsorption; Thermodynamic; Regeneration

Photocatalytic performance of cylindrical reactor inserted with UV light-emitting-diodes for purification of low-level toxic volatile organic compounds by Wan K. Jo; Hyun J. Kang (pp. 657-663).

► Photocatalyst baked at 350°C exhibited the highest BTEX degradation efficiency. ► Conventional lamp evidenced a higher degradation efficiency compared to LEDs. ► LEDs was more energy-efficient than conventional lamp for BTEX degradation. ► As the residence time increased, the average degradation efficiency increased.The present study investigated the photocatalytic performance of a cylindrical reactor inserted with UV light-emitting-diodes for the decomposition of low-level (0.1ppm) gas-phase organic compounds (benzene, toluene, ethyl benzene and xylene (BTEX)). The morphological and optical properties of photocatalysts (Degussa P-25 TiO₂) baked at different temperatures were determined using a range of spectral instruments. The photocatalyst baked at 350°C exhibited the highest conversion efficiencies for both benzene and toluene (81 and ∼100%, respectively). The conventional lamp showed a higher conversion efficiency for benzene compared to the 380-nm UV-LED and a higher conversion efficiency for benzene and toluene than the 365-nm UV-LED. However, the ratios of conversion efficiency to electric power consumption were 2.5–3.0 times higher for the latter light source than the former source. Moreover, as the residence time increased from 0.2 to 1.2min, the average conversion efficiencies for BTEX of the 3-h photocatalytic process increased from nearly zero to 81%, 7 to nearly 100%, 20 to nearly 100%, and 29–30 to nearly 100%, respectively. The cylindrical photocatalytic reactor inserted with UV-LEDs could be energy-efficiently applied for the decomposition of low-level toxic compounds after optimization of the operating conditions.

Keywords: Photocatalytic conversion; Electric power consumption; Energy-efficiency; Baking temperature; Residence time

Synergy effect of naphthenic acid corrosion and sulfur corrosion in crude oil distillation unit by B.S. Huang; W.F. Yin; D.H. Sang; Z.Y. Jiang (pp. 664-670).

► The corrosion of a carbon–manganese steel and a stainless steel in sulfur and/or naphthenic acid media was investigated. ► The corrosion rate of the carbon–manganese steel increased with the increase of the acid value and sulfur content. ► The critical values of the concentration of sulfur and acid for corrosion rate of the stainless steel were ascertained respectively. ► The stainless steel is superior to the carbon-manganese steel in corrosion resistance because of the presence of stable Cr₅S₈ phases.The synergy effect of naphthenic acid corrosion and sulfur corrosion at high temperature in crude oil distillation unit was studied using Q235 carbon-manganese steel and 316 stainless steel. The corrosion of Q235 and 316 in corrosion media containing sulfur and/or naphthenic acid at 280°C was investigated by weight loss, scanning electron microscope (SEM), EDS and X-ray diffractometer (XRD) analysis. The results showed that in corrosion media containing only sulfur, the corrosion rate of Q235 and 316 first increased and then decreased with the increase of sulfur content. In corrosion media containing naphthenic acid and sulfur, with the variations of acid value or sulfur content, the synergy effect of naphthenic acid corrosion and sulfur corrosion has a great influence on the corrosion rate of Q235 and 316. It was indicated that the sulfur accelerated naphthenic acid corrosion below a certain sulfur content but prevented naphthenic acid corrosion above that. The corrosion products on two steels after exposure to corrosion media were investigated. The stable Cr₅S₈ phases detected in the corrosion products film of 316 were considered as the reason why 316 has greater corrosion resistance to that of Q235.

Keywords: Synergy corrosion; Naphthenic acid; Sulfur; High temperature

Citric acid-assisted hydrothermal synthesis and luminescence of monodisperse NdPO₄ nanorods by Ting Fan; Jiantao Lü (pp. 671-673).

► Monodisperse NdPO₄ nanorods were prepared by a facile citric acid-assisted hydrothermal process. ► Citric acid promoted the 1D growth and increased the steric hindrance, leading to the forming of monodisperse nanorods. ► This common hydrothermal method can successfully produce high-quality crystalline nanowires. ► The products will be suitable for nanodevices and other applications.Hexagonal monodisperse NdPO₄ nanorods with 300–500nm in length and 30–50nm in width were prepared through a facile citric acid-assisted hydrothermal reaction. The products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR) spectra and photoluminescence spectra at room temperature. The addition of citric acid did not influence the phase of samples and the luminescence of Nd³⁺ ions but promoted the 1D growth of NdPO₄ crystals and increased the steric hindrance, leading to the forming of monodisperse nanorods.

Keywords: Hydrothermal reaction; Lanthanide; Phosphates

Microstructure and elevated-temperature erosion-oxidation behaviour of aluminized 9Cr-1Mo Steel by E. Huttunen-Saarivirta; M. Honkanen; S.A. Tsipas; H. Omar; D. Tsipas (pp. 674-684).

► Aluminized coatings are applied on 9Cr-1Mo steel at 715°C by a pack cementation method. ► The obtained coatings are characterized in terms of microstructure and resistance to erosion-oxidation at 550–700°C. ► The outermost coating layer is Al-rich and contains e.g., AlN precipitates. ► The coating provides the substrate increased protection particularly against normal particle impacts. ► A homogeneous layer of erodent particle debris formed on the specimen surfaces.Degradation of materials by a combination of erosive wear and atmospheric oxidation at elevated temperatures constitutes a problem in some power generation processes, such as fluidized-bed combustion. In this work, 9Cr-1Mo steel, a common tube material in combustion chambers, is coated by a pack cementation method from an Al-containing pack in order to improve the resistance to erosion-oxidation at elevated temperatures. The resulting coating is studied in terms of microstructure and microhardness and tested for its resistance against impacts by sand particles in air at temperatures of 550–700°C under several conditions, with thickness changes and appearance of the exposed surfaces being studied. The coating was found to contain several phases and layers, the outermost of which was essentially Al-rich and contained e.g., small AlN precipitates. The microhardness values for such coating ranged from 950 to 1100HV_20g. The coating provided the substrate with increased protection particularly against normal particle impacts, as manifested by smaller thickness losses for coated specimens as compared to uncoated counterparts. However, much of the coating was lost under all test conditions, despite the fact that particle debris formed a homogeneous layer on the surface. These results are described and discussed in this paper.

Keywords: Coating; Steel; Pack cementation; Erosion-oxidation; Microhardness

Effect of propane/silane ratio on the growth of 3C-SiC thin films on Si(100) substrates by APCVD by Biao Shi; Xue-Chao Liu; Ming-Xing Zhu; Jian-Hua Yang; Er-Wei Shi (pp. 685-690).

► 3C-SiC films were grown on Si(100) substrates at 1200°C by atmospheric pressure CVD. ► The C/Si was varied from 2.0 to 3.6 and its effect was investigated. ► 3C-SiC films exhibit epitaxial nature with pyramid-like morphology for C/Si<2.8. ► 3C-SiC films showed polycrystalline columnar grains with rounded shape for C/Si≥2.8. ► The difference in crystalline properties is attributed to secondary nucleation rate.3C-SiC thin films were grown on Si(100) substrates at 1200°C by atmospheric pressure chemical vapor deposition. We performed an in-depth study on the effect of propane/silane ratio (it is expressed by C/Si which means the ratio of C atom to Si atom in propane and silane) on crystalline quality and microstructure of 3C-SiC thin films. The 3C-SiC thin films exhibit epitaxial nature with pyramid-like morphology or polycrystalline columnar grains with rounded shape, which are dependent on C/Si ratio. The growth mechanism of 3C-SiC film with different C/Si ratios is discussed based on the cross-sectional transmission electron microscopy characterization. The changes in crystalline and microstructure with increasing C/Si ratio are attributed to high secondary nucleation rate.

Keywords: 3C-SiC film; Chemical vapor deposition; Gas phase composition; Nucleation

Pulsed DC discharge for synthesis of conjugated plasma polymerized aniline thin film by Tapan Barman; Arup R. Pal (pp. 691-697).

► Pulsed DC plasma has been used for synthesis of conducting polymer film. ► Conjugated structure retention is possible in the pulsed DC plasma. ► Pulsed DC is found to be advantageous for deposition of conjugated film.The polymerization of aniline in pulsed dc plasma is studied and the effects of variation of pressure, power, frequency and duty cycle on the chemical structure of the obtained film are examined. During the film deposition optical emission spectroscopy is used to investigate the molecular dissociation of aniline. The chemical structure of the films is characterized using Fourier transform infra-red spectroscopy. The surface morphology is studied using atomic force microscopy. Results show the retention of polyaniline like structure having conjugated nature at some particular discharge conditions. Moreover, it is observed that a strong dependence of film chemistry is obvious on the discharge power, reactor pressure, pulse repetition frequency and duty cycle. The advantages of the pulsed dc for deposition of conjugated plasma polymerizes thin film have been highlighted.

Keywords: PACS; 52.77.Dq; 52.80.Pi; 81.07.PrPulsed DC plasma deposition; Conjugated polymer; Glow discharge; Thin film

Preparation high photocatalytic activity of CdS/halloysite nanotubes (HNTs) nanocomposites with hydrothermal method by Weinan Xing; Liang Ni; Pengwei Huo; Ziyang Lu; Xinlin Liu; Yingying Luo; Yongsheng Yan (pp. 698-704).

► CdS/halloysite nanotubes (HNTs) were synthesized by hydrothermal method. ► The CdS/HNTs had better photocatalytic activity for degradation of tetracycline. ► The presence of halloysite nanotubes both improved its photocatalytic activity and stability.A novel nanocatalyst CdS/halloysite nanotubes (HNTs) was synthesized by hydrothermal method with direct growth of CdS nanoparticles on the surface of HNTs. The as-prepared photocatalysts had been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), UV–vis diffuse reflectance spectra (UV–vis DRS), Fourier transform infrared (FT-IR) and the thermo gravimetric analysis (TGA). The photocatalytic activity of the sample was evaluated by the degradation of tetracycline (TC) under visible light irradiation. Benefit from the excellent properties of CdS and HNTs, the photocatalyst exhibited good photocatalytic activity and stability. In order to find out the optimum synthesis condition to obtain the best photocatalytic activity, a series of experiments were performed with different CdS loading capacity, different sources of sulfide and different hydrothermal temperatures, etc. The best photodegradation rate could reach 93% in 60min under visible light irradiation. Therefore, the combination of CdS nanoparticles with HNTs endowed this material with a potential use in environmental treatments in industries.

Keywords: CdS; Halloysite nanotube; Hydrothermal method; Photocatalysis; Tetracycline

Multiscaled hierarchical nanostructures for enhancing the conversion efficiency of crystalline silicon solar cells by Bingfa Liu; Shenyu Qiu; Ruiyi Hu; Yuanbin Liao; Nan Chen; Guoping Du (pp. 705-710).

► Er doped ZnO (EZO) nanotip arrays were successfully grown on SiN x-coated silicon solar cells. ► The EZO nanotip arrays (NTAs) were very effective in reducing optical reflection of solar cell. ► EZO NTAs were grown evenly on all faces of the texturized pyramids of silicon solar cell. ► EZO NTAs resulted in a large improvement in the conversion efficiency of silicon solar cell.High-performance antireflection structure is critical for enhancing the conversion efficiency of solar cells. One of the most effective antireflection techniques for solar cells is the introduction of nanostructures to the cells. In this work, we prepared multiscaled hierarchical Er-doped ZnO nanostructures on the plasma enhanced chemical vapor deposited silicon nitride-coated texturized single crystalline silicon solar cells for antireflection. The multiscaled hierarchical Er-doped ZnO nanostructures were needle-like nanotip arrays, and they were grown using the hydrothermal method. The dependence of microstructure and antireflection performance of the multiscaled hierarchical Er-doped ZnO nanostructures on the growth time were studied. It was shown that longer growth time resulted in greater length and diameter for the Er-doped ZnO nanostructures. For longer growth time, the needle-like tips of the multiscaled hierarchical Er-doped ZnO nanostructures were found to transform to flat tops, which greatly degraded their antireflection performance. An optimal growth time for the multiscaled hierarchical Er-doped ZnO nanostructures was determined, and a large enhancement in the photovoltaic performance of sc-Si solar cells was resulted.

Keywords: Hierarchical nanostructure; Er-doped ZnO; Nanotip array; Antireflection; Solar cell

Formation and characterization of wear-resistant PEO coatings formed on β-titanium alloy at different electrolyte temperatures by H. Habazaki; S. Tsunekawa; E. Tsuji; T. Nakayama (pp. 711-718).

► Wear-resistant coatings are formed on β-titanium alloy by plasma electrolytic oxidation. ► Better coatings are formed at lower electrolyte temperatures. ► High speed video imaging was used to monitor the discharge behavior during the process.Plasma electrolytic oxidation of single β-phase Ti–15 mass% V–3 mass% Al–3 mass% Cr–3 mass% Sn (hereafter denoted as Ti–15–3) alloy has been conducted in alkaline aluminate electrolyte at different electrolyte temperatures between 278 and 313K. The results obtained disclose the highly improved wear resistance of the coatings formed at the lowest temperature of 278K. The coating formed at this temperature has lower porosity and contains higher concentration of α-Al₂O₃ phase in addition to the Al₂TiO₅ major phase. In contrast, non-uniform coatings are formed at higher temperatures and their porosity is relatively high. Thus, the highest wear resistance of the Ti–15–3 is obtained when the coating is formed at 278K. Such influence of the electrolyte temperature on the coating morphology and composition is discussed by direct imaging based on direct video imaging data during the coating process.

Keywords: Plasma electrolytic oxidation; Ceramic coating; Titanium alloy; Wear resistance; High speed video imaging

Synthesis and characterization of superhydrophobic and superparamagnetic film based on maghemite–polystyrene composite nanoparticles by L.D. Zhang; W.L. Liu; W.H. Xu; J.S. Yao; L. Zhao; X.Q. Wang; Y.Z. Wu (pp. 719-725).

► Maghemite nanoparticles were coated with silica. ► Polystyrene was grafted onto the surface of silica coated maghemite. ► The rough surface shows superhydrophobic and superparamagnetic properties.We combine two abilities: the superhydrophobicity of lotus leaf and the magnetic property of γ-Fe₂O₃. A superhydrophobic and superparamagnetic polystyrene/silica/maghemite (PS/SiO₂/γ-Fe₂O₃ (PSVSF)) film was prepared by a three-step chemical procedure at mild conditions. The products exhibited superhydrophobicity and superparamagnetism after coating and modifying. Because PS and SiO₂ supplied the low surface energy and roughness, respectively. In addition, the classic and a modified Cassie–Baxter relation were applied on the PSVSF films to verify the superhydrophobic performance. It indicates that the obtained superhydrophobic and superparamagnetic films are promising materials for numerous potential applications fields, including aerospace, electronic, biomedical, martial and defense-related areas.

Keywords: Superhydrophobic; Superparamagnetic; Maghemite; Polystyrene; Silica; Film

Influence of multi-hit capability on quantitative measurement of NiPtSi thin film with laser-assisted atom probe tomography by T. Kinno; H. Akutsu; M. Tomita; S. Kawanaka; T. Sonehara; A. Hokazono; L. Renaud; I. Martin; R. Benbalagh; B. Sallé; S. Takeno (pp. 726-730).

► Laser-assisted atom probe tomography was applied to NiPtSi films on Si substrates. ► Comparison of depth profiles of single-hit events and those of multi-hit events. ► ∼80% of Pt atoms were detected in multi-hit events. ► Multiple-ion detection is important for Laser-assisted atom probe tomography.Laser-assisted atom probe tomography (LA-APT) was applied to NiPtSi (0, 30, and 50% Pt contents) thin films on Si substrates. Consistent results with those of high-resolution Rutherford backscattering spectrometry (HR-RBS) were obtained. Based on the obtained data sets, the composition profiles from only the signals of single-hit events, meaning detection of one ion by one laser pulse, were compiled. The profiles from only the signals of multi-hit events, meaning detection of multiple ions by one laser pulse, were also compiled. There were large discrepancies with respect to Ni and Pt concentrations among the compiled profiles and the original profiles including the signals of both types of detection events. Additionally, the profiles compiled from single-hit events showed that Si concentration in NiPtSi layer became smaller toward the surface, differing from the original profiles and the multi-hit profiles. These results suggest that capability of simultaneous multiple-ion detection is important for appropriate LA-APT analyses.

Keywords: APT; Laser-assisted; Atom probe; NiPtSi; Depth profile

Paper surfaces for metal nanoparticle inkjet printing by Thomas Öhlund; Jonas Örtegren; Sven Forsberg; Hans-Erik Nilsson (pp. 731-739).

► Electrical conductivity is highly dependent on surface characteristics. ► Porosity and surface roughness are very important factors for conductivity. ► Surface energy is a minor factor for absorbing and rough substrates. ► If well behaved, porosity and roughness can be harmless or even beneficial. ► Paper substrates can be high performance substrates for metal nanoparticle inks.The widespread usage of paper and board offer largely unexploited possibilities for printed electronics applications. Reliability and performance of printed devices on comparatively rough and inhomogenous surfaces of paper does however pose challenges.Silver nanoparticle ink has been deposited on ten various paper substrates by inkjet printing. The papers are commercially available, and selected over a range of different types and construction. A smooth nonporous polyimide film was included as a nonporous reference substrate. The substrates have been characterized in terms of porosity, absorption rate, apparent surface energy, surface roughness and material content. The electrical conductivity of the resulting printed films have been measured after drying at 60°C and again after additional curing at 110°C. A qualitative analysis of the conductivity differences on the different substrates based on surface characterization and SEM examination is presented. Measurable parameters of importance to the final conductivity are pointed out, some of which are crucial to achieve conductivity. When certain criteria of the surfaces are met, paper media can be used as low cost, but comparably high performance substrates for metal nanoparticle inks in printed electronics applications.

Keywords: Printed electronics; Inkjet printing; Paper substrates; Flexible substrates; Nanoparticles; Conductive inks

Effect of UV laser irradiation on the hardness and structural parameters of Ag_xPd1−_x (0.4≤ x≤0.6) alloys by M.Z. Butt; Farooq Bashir; Shamaila Arooj (pp. 740-746).

► Surface hardness of AgPd alloy specimens increases with increasing number of laser shots. ► Increase in surface hardness per laser shot is maximum for Ag₅₀Pd₅₀. ► Surface hardness is a function of dislocation line density, which increases with increasing number of laser shots. ► Hardness profile shows a decreasing trend till a distance of 3mm from midpoint of the laser spot.Strips of high-purity Ag_xPd1−_x alloys, with x=0.4, 0.5 and 0.6, were solution treated at 800°C for 2h. Specimens of each composition were then irradiated with 100, 200, 300, and 400 shots of KrF Excimer laser (maximum energy 20mJ, wavelength 248nm, pulse width 20ns, repetition rate 20Hz). For each alloy, Vickers hardness of un-irradiated and irradiated specimens was measured as a function of the number of laser shots, and was found to increase with increasing number of shots. The increase in surface hardness at the midpoint of laser irradiation spot on Ag₄₀Pd₆₀, Ag₅₀Pd₅₀, and Ag₆₀Pd₄₀ specimens was up to 27.6, 30.2, and 17.3%, respectively. The surface hardness profile for each irradiated specimen shows a decreasing trend till a distance of 3mm from the midpoint of the irradiated spot. XRD study of the alloy specimens of each composition shows that the dislocation line density increases with increasing number of shots, and the surface hardness is a function of it.

Keywords: AgPd alloys; UV laser; XRD; Hardness; Hall–Petch relation

Substrate-tilt angle effect on structural and optical properties of sputtered ZnO film by Hua Feng Pang; Guang An Zhang; Yong Liang Tang; Yong Qing Fu; Li Ping Wang; Xiao Tao Zu; Frank Placido (pp. 747-753).

► New one-step deposition of ZnO films utilizing a special holder was developed. ► ZnO films with different column inclination angles were obtained simultaneously. ► With increasing substrate tilt angle from 0° to 34°, the film stress in ZnO films decreases and the band-gap energies also decrease from 3.19eV to 3.07eV.A new one-step method utilizing a special holder for a direct current magnetron sputtering system has enabled simultaneous deposition of ZnO films with different substrate tilt angles on quartz and silicon substrates. Observation from scanning electron microscopy shows that a typical columnar structure is obtained and the column inclination angle varies from 0° to 34°. From X-ray diffraction analysis, the strains in the ZnO films decrease with increasing substrate tilt angle, which is confirmed by the variation of the longitude optical phonon vibration in the Raman spectra. The band-gap energies decrease from 3.19eV to 3.07eV mainly due to the changes of strain relaxation induced by the defect variations in the films. Photoluminescence spectra revealed that the generation, type and concentration of the complex defects are influenced by the substrate tilt angle.

Keywords: Sputtered ZnO film; Substrate tilt angle; Band-gap energy; Photoluminescence; New one-step method

Effect of atomic deuterium irradiation on initial growth of Sn and Ge1−_xSn_x on Ge(001) substrates by Tatsuya Shinoda; Osamu Nakatsuka; Yosuke Shimura; Shotaro Takeuchi; Shigeaki Zaima (pp. 754-757).

► The irradiation effect of atomic deuterium on the initial growth of Sn and Ge1−_xSn_x on Ge(001) has been investigated. ► The surfactant effect appears and the surface roughness is reduced when the surface coverage of deuterium or hydrogen is higher than 69%. ► The efficiency for reducing the surface roughness increases with the coverage of deuterium and hydrogen. ► Deuterium atoms effectively work as a surfactant on the Ge surface compared to hydrogen.We have investigated the effect of the irradiation of atomic deuterium (D) on the initial growth of Sn and Ge1−_xSn_x on Ge(001) substrates by using scanning tunneling microscopy (STM) comparing to the effect of the irradiation of atomic hydrogen (H). We found that the surfactant effect appears and the surface roughness is reduced when the surface coverage of D or H is higher than 69%. The efficiency for reducing the surface roughness increased with the coverage of D and H. Moreover, we found that D atoms effectively work as a surfactant on the Ge surface compared to H atoms under the same irradiation condition. Utilizing D as a surfactant is expected to improve the termination process of Ge surface.

Keywords: Germanium; Tin; Hydrogen; Epitaxial growth; Surface; Scanning tunneling microscopy

A study of ZnO:B films for thin film silicon solar cells by J. Yin; H. Zhu; Y. Wang; Z. Wang; J. Gao; Y. Mai; Y. Ma; M. Wan; Y. Huang (pp. 758-763).

► ZnO:B films with different thicknesses were prepared with LPCVD technique. ► The thicker ZnO:B back electrodes lead to higher FF but slightly lower J_sc. ► Back polyvinyl butyral (PVB) foils improves the utilization of incident light in solar cells. ► The thicker ZnO:B front electrode films result in high J_sc but lower FF.Boron doped zinc oxide (ZnO:B) films with different thicknesses were prepared with low pressure chemical vapor deposition (LPCVD) technique and implemented in thin film silicon solar cells as front and back electrodes. It is found that thick back ZnO:B film electrode in thin film silicon solar cells leads to a high fill factors (FF), which is attributed to an improvement of the electrical properties of the thick ZnO:B films, and in the meanwhile a slightly low short circuit currents ( J_sc) due to a high light absorption in the thick back ZnO:B films. Differently, the thicker front ZnO:B film electrodes result in a high J_sc but a low FF of solar cells compared to the thinner ones. The low FF of the solar cells may be caused by the local shunt originated from the pinholes or by the cracks (zones of non-dense material) formed in particular in microcrystalline silicon materials deposited on rough front ZnO:B films. As to the high J_sc, it is expected to be due to a good light trapping effect inside solar cells grown on rough front ZnO:B films. Moreover, the application of high reflective polyvinyl butyral (PVB) foils effectively enhances the utilization of incident light in solar cells. By optimizing deposition process of the ZnO:B films, high efficiencies of 8.8% and 10% for single junction thin film amorphous silicon solar cells (a-Si:H, intrinsic layer thickness<200nm) and amorphous/microcrystalline silicon tandem solar cells (a-Si:H/μc-Si:H, intrinsic amorphous silicon layer thickness<220nm), respectively, are achieved.

Keywords: Thin film silicon solar cells; ZnO:B film; Light trapping; LPCVD

Preparation and anti-icing of superhydrophobic PVDF coating on a wind turbine blade by Chaoyi Peng; Suli Xing; Zhiqing Yuan; Jiayu Xiao; Chunqi Wang; Jingcheng Zeng (pp. 764-768).

► A porous superhydrophobic PVDF coating was prepared on a wind turbine blade. ► The present method of preparing superhydrophobic coating is novel and simple. ► The superhydrophobic PVDF coating showed excellent anti-icing.A novel and simple method was developed to prepare a porous superhydrophobic polyvinylidene fluoride (PVDF) coating on a wind turbine blade. The water contact angle and sliding angle of the superhydrophobic PVDF coating were 156±1.9° and 2°, respectively. The superhydrophobic PVDF coating showed excellent anti-icing property. The present work will provide a new way to fabricate anti-icing coating on wind turbine blades and other outdoor equipments.

Keywords: Anti-icing; Superhydrophobic; PVDF; Coating; Wind turbine blade

Electrostatic spray deposition of nanoporous CoO/Co composite thin films as anode materials for lithium-ion batteries by Yi Sun; Chun Du; Xu-Yong Feng; Yan Yu; Ingo Lieberwirth; Chun-Hua Chen (pp. 769-773).

► The films are made of in situ produced hollow spheres consisting of conductive Co and electrochemically active CoO. ► The homogeneous distribution of Co revealed by EELS in the film is important for the good rate capability. ► The CoO/Co composite films exhibit excellent rate performance with 69.5% of capacity retention at 10C.Cobalt alkoxide suspension is obtained by heating a mixed polyalcohol solution of cobalt acetate in an oil bath at 170°C. Thermogravimetric analysis is adopted to determine the chemical formula of the alkoxide powder in the suspension. With the suspension precursors, CoO/Co composite thin films are fabricated by electrostatic spray deposition and subsequent heat treatment in nitrogen. They are characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Electron energy loss spectroscopy mapping is applied to determine the lateral two-dimensional chemical distribution of metallic Co in the nanocomposites. The thin film can deliver a high reversible capacity of 1182.1mAhg⁻¹ at 70th cycle and retain 69.5% of the initial capacity at 10C. The in situ production of metallic cobalt and the unique hollow structure of the particles can account for the good electrochemical performance.

Keywords: Cobalt oxide; Anode materials; Electron energy loss spectroscopy; Hollow structure; Lithium ion battery

Hydrophobically modified sodium humate surfactant: Ultra-low interfacial tension at the oil/water interface by Jianmei Zhang; Gang Li; Fang Yang; Nian Xu; Hongxian Fan; Tao Yuan; Lin Chen (pp. 774-779).

Display Omitted► Modified sodium humate surfactants can be used to enhance oil recovery. ► The interfacial activity of oil/water interface is obviously improved. ► Surfactant mixed with Na₃PO₄ and n-propanol presents the lowest interfacial tension. ► The minimum interfacial tension is 10⁻⁵mN/m.Hydrophobically modified sodium humate surfactants with different chain lengths (C_n-HANa, n=10, 12, 14, 18) were synthesized in this paper and the molecular structures were confirmed by FT-IR and UV–vis spectra. The effects of C_n-HANa, alcohol (ethanol, n-propanol, iso-propanol, n-butbanol) and alkaline (KOH, NaOH, Na₂CO₃, Na₃PO₄·12H₂O, NaOH:Na₂CO₃) on the interfacial tension of oil/water interface were investigated by KRUSS SITE-100 spinning drop interfacial tension apparatus. Ultra-low interfacial tension related to enhanced oil recovery (EOR) was obtained at the crude oil/water interface from the mixture solution of the C_n-HANa surfactant, Na₃PO₄·12H₂O and n-propanol. The experimental results show that hydrophobic modification of sodium humate surfactants cause low interfacial tension at the crude oil/water interface as compared with those of the single sodium humate. While the interfacial tension of the C_n-HANa/crude oil interface could reach to 10⁻¹mN/m, the interfacial tension of the C_n-HANa/Na₃PO₄·12H₂O/crude oil system, in aqueous solution, decreases so much that sometimes it is less than 10⁻⁴mN/m. Furthermore, n-propanol is added to the C₁₀-HANa/Na₃PO₄·12H₂O/crude oil system, it can make the range of the ultra-low interfacial tension extend from 0.20–0.30% to 0.20–0.70% for Na₃PO₄·12H₂O, and the minimum interfacial tension is 5.27×10⁻⁵mN/m at Na₃PO₄·12H₂O concentration about 0.35%.

Keywords: Hydrophobically modified sodium humate surfactant; Sodium phosphate; n; -Propanol; Ultra-low interfacial tension

Numerical prediction of heat affected layer in the EDM of aeronautical alloys by B. Izquierdo; S. Plaza; J.A. Sánchez; I. Pombo; N. Ortega (pp. 780-790).

► A multi-discharge thermal numerical model has been used to simulate successive crater superposition. ► Discharge properties have been inversely estimated for four different EDM regimes. ► Data regarding discharge characteristics have been employed to predict the formation of recast layer. ► Calculated errors are around 10% except for the most energetic regime. ► Energetic efficiency of discharges has been analyzed for the characterized regimes.Electrical discharge machining is a popular non-traditional machining process, optimum for accurate machining of complex geometries in hard materials. EDM has been used for decades for machining pieces for the aeronautical industry, but surface integrity, and consequently the reliability of the machined parts have been questioned for long time due to the thermal nature of this machining process. In recent years, efforts have been put on modeling of the EDM process, being thermal modeling of the process one promising alternative. In a previous publication an original model of the EDM process was presented and it was used to predict material removal rate and surface finish for the EDM of steel. In the present article the capability of that modeling tool to characterize discharge properties and to predict recast layer distribution when EDMing an aeronautical alloy will be analyzed. EDM process of Inconel 718 has been studied and discharge properties have been obtained for four different EDM regimes. The capability of the model to reflect the behavior of more energetic regimes is discussed. Gathered information has been used to simulate the evolution of the recast layer generation process. Obtained results have been validated comparing them with experimental measurements, revealing a good correlation between predictions and experimental data. Finally, energetic efficiency of the discharge process has been simulated for the adjusted EDM regimes.

Keywords: Aeronautical alloys; EDM; Recast layer; Thermal modeling

Influence of the surface morphology on the early stages of Cu oxidation by Langli Luo; Yihong Kang; Judith C. Yang; Guangwen Zhou (pp. 791-798).

► The growth morphology of Cu films is controllable via deposition temperature. ► The initial oxide formation can be modified by the surface morphology of Cu films. ► Increasing surface roughness enhances oxide nucleation but suppresses oxide growth.The growth and morphological features of Cu films deposited on NaCl(100) by e-beam evaporation have been examined to evaluate the effect of various surface morphologies on the initial oxidation of Cu. It is shown that epitaxial Cu films with significantly reduced surface roughness can be achieved by first nucleating Cu seeds at 450°C that favors epitaxial Cu grains which is followed by subsequent seed growth at 150°C that favors smooth Cu film. The effect of the variations of the surface morphology of the resulting Cu films by the different growth conditions on the early stages oxidation of Cu films is examined by in situ transmission electron microscopy (TEM) and ex situ atomic force microscopy (AFM). It is shown that the changes in the surface morphologies of the Cu film result in distinct variations in the nucleation density and growth rates of oxide islands. Such correlation between the surface morphology and the initial oxidation behavior of the Cu films provides insights into understanding the microscopic processes of the transient oxidation of metals and for manipulating the initial oxide formation through surface treatments.

Keywords: Surface morphology; Oxidation; Copper; Electron microscopy; Atomic force microscopy

Bioactive glass–ceramic coating for enhancing the in vitro corrosion resistance of biodegradable Mg alloy by Xinyu Ye; Shu Cai; Ying Dou; Guohua Xu; Kai Huang; Mengguo Ren; Xuexin Wang (pp. 799-805).

► Sol–gel derived 45S5 glass–ceramic coating was prepared on Mg alloy substrate. ► The corrosion resistance of glass–ceramic coated Mg alloy was markedly improved. ► The corrosion behavior of the coated sample varied due to the cracking of coating.In this work, a bioactive 45S5 glass–ceramic coating was synthesized on magnesium (Mg) alloy substrate by using a sol–gel dip-coating method, to improve the initial corrosion resistance of AZ31 Mg alloy. The surface morphology and phase composition of the glass–ceramic coating were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The coating composed of amorphous phase and crystalline phase Na₂Ca₂Si₃O₉, with the thickness of ∼1.0μm, exhibited a uniform and crack-free surface morphology. The corrosion behavior of the uncoated and coated Mg alloy substrates was investigated by the electrochemical measurements and immersion tests in simulated body fluid (SBF). Potentiodynamic polarization tests recorded an increase of potential ( E_corr) form −1.60V to −1.48V, and a reduction of corrosion current density ( i_corr) from 4.48μAcm⁻² to 0.16μAcm⁻², due to the protection provided by the glass–ceramic coating. Immersion tests also showed the markedly improved corrosion resistance of the coated sample over the immersion period of 7 days. Moreover, after 14 days of immersion in SBF, the corrosion resistance of the coated sample declined due to the cracking of the glass–ceramic coating, which was confirmed by electrochemical impedance spectroscopy (EIS) analysis. The results suggested that the 45S5 glass–ceramic coated Mg alloy could provide a suitable corrosion behavior for use as degradable implants.

Keywords: Magnesium alloy; Glass–ceramic coating; Corrosion resistance; Biomaterials

Room temperature pulsed laser deposited ZnO thin films as photoluminiscence gas sensors by D. Padilla-Rueda; J.M. Vadillo; J.J. Laserna (pp. 806-810).

Display Omitted► Elaboration of functional ZnO thin films by PLD at room temperature is possible. ► Fluorescence quenching of ZnO thin films may be used for NO₂ sensors. ► Addition of oxygen during deposition is required to get films of better quality. ► Films exhibited linear behaviour in the range between 26 and 100ppm.Zinc oxide thin films with optical sensing capabilities for NO₂ have been elaborated by pulsed laser deposition (PLD) onto glass substrates at room temperature with Nd:YAG laser (1064nm). Morphology, chemical composition and optical characteristics of the films were evaluated as a function of laser fluence, gas pressure and target-to-substrate distance. Films exhibit excellent morphological and optical (transmittance and photoluminescence) properties. The films have been evaluated as fluorescence sensors for NO₂ in the concentration range between 26 and 200ppm.

Keywords: PLD; ZnO film; Pulsed laser deposition; Room temperature films; Opto-sensor NO; ₂

Magnetron sputtering SiC films on nickel photonic crystals with high emissivity for high temperature applications by Zhenyu Li; Lili Yang; Dengteng Ge; Yanbo Ding; Lei Pan; Jiupeng Zhao; Yao Li (pp. 811-815).

► SiC on Ni PCs was prepared by electrodeposition and magnetron sputtering. ► SiC reveals two-dimensional patterned structures due to their preferential growth. ► Ni PCs/SiC has enhanced emissivity due to periodic structure and rough surfaces.High emissivity coatings have been widely used in many high temperature applications. Here we report a novel structure of magnetron sputtering silicon carbide (SiC) films on Ni photonic crystals (PCs) to improve emissivity performance. It is found that SiC coatings reveal two-dimensional patterned structures due to their preferential growth on the skeleton of Ni PCs. The spectral emissivity results show periodic structures and surface-porous structured SiC can enhance the coatings’ spectral emissivity because of higher rough surface, lower reflectivity and magnitude of thermal fluctuations. The method holds promising potential for preparing a series of high emissivity coatings and highly ordered metal–ceramics composites microstructures for thermophotovoltaic (TPV) radiator, pyroelectric and other photonics applications.

Keywords: Emissivity; SiC; Sputtering; Patterned structure

Effect of Zn content on the chemical conversion treatments of AZ91D magnesium alloy by Lifang Hu; Qingsen Meng; Shaoping Chen; Hao Wang (pp. 816-823).

► The effect of Zn content on the chemical conversion process of Mg alloy was studied. ► The coating thickness grows up with the increase of the Zn content. ► The corrosion resistance of the coating is comparable if the Zn content below 2wt.%. ► The corrosion resistance of the coating became poorer if the Zn content beyond 2wt.%.In this study, four AZ91D magnesium plates with different Zn content were treated with chemical conversion treatments. The chemical conversion coating was examined using scanning electron microscope, optical microscope and glow discharge optical emission spectrometer. The testing results indicated that increase in Zn content produced a thicker chemical conversion coating. However, when the Zn content exceeded 2wt.%, the thickness of the chemical conversion coating decreased. To investigate the chemical conversion mechanism, potentiodynamic polarization and electrochemical impedance spectroscopy were employed to evaluate the corrosion resistance of the magnesium substrate in 3.5wt.% NaCl solution.

Keywords: AZ91D; Magnesium alloy; Chemical conversion coating; Zn content; Corrosion

Preparation and tribological properties of water-soluble copper/silica nanocomposite as a water-based lubricant additive by Chunli Zhang; Shengmao Zhang; Laigui Yu; Zhijun Zhang; Zhishen Wu; Pingyu Zhang (pp. 824-830).

Display Omitted► A facile process is established to prepare water-soluble Cu/SiO₂ nanocomposite. ► Cu/SiO₂ nanocomposite exhibit markedly improved tribological properties. ► The state and thickness of the film on worn surface is closely related to applied load.Cu/SiO₂ nanocomposite was synthesized by sol–gel method. The size, morphology and phase structure of as-prepared Cu/SiO₂ nanocomposite were analyzed by means of X-ray diffraction and transmission electron microscopy, and its ultraviolet-visible light spectrum was measured in relation to surface plasmon excitation of Cu particles. The tribological properties of as-synthesized Cu/SiO₂ nanocomposite as an additive in distilled water were investigated with a four-ball machine, and the morphology and elemental composition of worn steel surfaces were examined with a scanning electron microscope and an X-ray photoelectron spectroscope. Results show that as-synthesized Cu/SiO₂ nanocomposite as a lubricant additive is able to significantly improve the tribological properties of distilled water. A protective and lubricious film composed of Cu and a small amount of FeS, FeSO₄ and SiO₂ is formed on steel sliding surfaces lubricated by distilled water containing Cu/SiO₂ nanocomposite. During friction process Cu nanoparticles can be released from Cu/SiO₂ nanocomposite to fill up micro-pits and grooves of steel sliding surfaces, resulting in greatly reduced friction and wear of steel frictional pair via self-repairing. The state and thickness of the film formed on the worn surface is closely related to applied load; and Cu/SiO₂ nanocomposite might be a promising water-based lubricant additive for steel-steel contact subjected to moderate load.

Keywords: Copper nanoparticles; Cu/SiO; ₂; nanocomposite; Lubricant additive; Preparation; Tribological properties

DRIFTS study of CO adsorption on praseodymium modified Pt/Al₂O₃ by I. Tankov; W.H. Cassinelli; J.M.C. Bueno; K. Arishtirova; S. Damyanova (pp. 831-839).

Display Omitted► Well dispersed platinum is observed over alumina modified with Pr. ► There is a strong Pt–O–Pr interaction. ► Pt⁰ and Pt^δ+ species are detected in reduced Pt samples.The effect of PrO₂ content (1–20wt.%) and temperature pretreatment on the structure and surface properties of PrO₂–Al₂O₃-supported Pt catalysts was studied by XRD, XPS and DRIFTS of carbon monoxide adsorption. XRD analysis showed that platinum particle size decreases with the increase of PrO₂ content for samples calcined at high temperature of 1023K. The intensity and position of the infrared bands were strongly dependent on the praseodymium oxide content and reduction temperature. Two kinds of Pt sites (Pt⁰ and Pt^δ+) were recorded in reduced PrO₂-containing samples. A better thermal stability of the PtCO bond in PrO₂-containing samples compared to Pt/Al₂O₃ was observed.

Keywords: DRIFT spectroscopy; CO adsorption; Platinum catalysts; Praseodymium oxide

Air plasma processing of poly(methyl methacrylate) micro-beads: Surface characterisations by Chaozong Liu; Nai-Yi Cui; Susan Osbeck; He Liang (pp. 840-846).

► PMMA micro-beads were processed using a rotary air plasma reactor. ► Surface chemistry and surface texture of PMMA micro-beads were characterised. ► Surface wettability was evaluated using “floating” water contact angle method. ► Surface oxidation and texture changes induced by air plasma attributed to the improvement of surface wettability.This paper reports the surface processing of poly(methyl methacrylate) (PMMA) micro-beads by using a rotary air plasma reactor, and its effects on surface properties. The surface properties, including surface wettability, surface chemistry and textures of the PMMA beads, were characterised. It was observed that the air plasma processing can improve the surface wettability of the PMMA microbeads significantly. A 15min plasma processing can reduce the surface water contact angle of PMMA beads to about 50° from its original value of 80.3°. This was accompanied by about 8% increase in surface oxygen concentration as confirmed by XPS analysis. The optical profilometry examination revealed the air plasma processing resulted in a rougher surface that has a “delicate” surface texture. It is concluded that the surface chemistry and texture, induced by air plasma processing, co-contributed to the surface wettability improvement of PMMA micro-beads.

Keywords: Air plasma processing; Poly(methyl methacrylate) beads; Wettability; Surface texture

Super-hydrophilic surfaces by photo-induced micro-folding by Thomas Bahners; Lutz Prager; Stefanie Kriehn; Jochen S. Gutmann (pp. 847-852).

► Totally wetting surfaces were prepared from UV cured acrylate layers. ► The process of photo-induced micro-folding was employed for large area treatments. ► Up to roughness factors of 1.2, the spreading followed a Wenzel-type behavior. ► Spreading on surfaces of more pronounced roughness was governed by surface features.A two-step UV curing process of thin acrylate layers was employed to prepare micro-rough top-coats on polymer film. The concept of the process (known as “photonic micro-folding”) is to apply a thin acrylate layer on a substrate and cure the layer by subsequent exposures to VUV and broad band UV radiation. The first curing step leads to curing of the skin of the acrylate layer alone, which induces shrinkage and folding. This structure is fixed in the second curing step which affects the bulk of the acrylate layer. The process is easily applied to any substrate and large areas. By using hydrophilic hydroxypropylacrylate and polyethylenglycolmonoacrylate as the main components of the applied acrylate, perfectly wetting – super-hydrophilic – surfaces were obtained. This basically is in accordance with the concept of Wenzel's equation which relates the apparent contact angle to a roughness factor r given by the ratio of true and projected surface area. The analysis of the data of this work, however, shows that the spreading of a droplet on surfaces with r>1.2 is governed by geometric effects such as blockage by the surface features and cannot by described by Wenzel's equation.

Keywords: Acrylate; UV curing; Photonic micro-folding; Superhydrophilic surface; Wenzel behavior

Impact of X-ray irradiation on PMMA thin films by Saman Iqbal; Muhammad Shahid Rafique; Safia Anjum; Asma Hayat; Nida Iqbal (pp. 853-860).

► PMMA thin films were deposited at 300°C and 500°C using PLD technique. ► These films were irradiated with different fluence of laser produced X-rays. ► Irradiation affects the ordered packing as well as surface morphology of film. ► Hardness of film decreases up to certain value of X-ray fluence. ► Absorption in UV–visible range exhibits a non linear behavior.The objective of this project is to explore the effect of X-ray irradiation of thin polymeric films deposited at various substrate temperatures. pulsed laser deposition (PLD) technique is used for the deposition of PMMA thin films on glass substrate at 300°C and 500°C. These films have been irradiated with various X-rays fluences ranging from 2.56 to 5.76mJcm⁻². Characterization of the films (before and after the irradiation) is done with help of X-ray Diffractrometer, Optical Microscope, Vickers hardness tester and UV–vis spectroscopy techniques. From XRD data, it is revealed that ordered packing has been improved for the films deposited at 300°C. However after irradiation the films exhibited the amorphous behavior regardless of the X-ray fluence. Film deposited at 500°C shows amorphous structure before and after irradiation. Hardness and particle size of thin film have also increased with the increasing substrate temperature. However, the irradiation has reverse effect i.e. the particle size as well as the hardness has reduced. Irradiation has also enhanced the absorption in the UV–visible region.

Keywords: Thin polymeric films; Pulsed laser deposition; Irradiation; X-rays fluence; UV–vis spectroscopy

Corrigendum to ‘Structural characteristics of mixed oxides MO_x/SiO₂ affecting photocatalytic decomposition of methylene blue’ [Appl. Surf. Sci. 258 (2012) 6288–6296] by V.M. Gun’ko; J.P. Blitz; B. Bandaranayake; E.M. Pakhlov; V.I. Zarko; I.Ya. Sulym; K.S. Kulyk; M.V. Galaburda; V.M. Bogatyrev; O.I. Oranska; M.V. Borysenko; R. Leboda; J. Skubiszewska-Zięba; W. Janusz (pp. 861-861).

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Applied Surface Science (v.259, #)