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Applied Surface Science (v.268, #)

Editorial Board (pp. ii).

Thermal stability of InN epilayers grown by high pressure chemical vapor deposition by Ananta R. Acharya; Sampath Gamage; M.K. Indika Senevirathna; Mustafa Alevli; Kucukgok Bahadir; Andrew G. Melton; Ian Ferguson; Nikolaus Dietz; Brian D. Thoms (pp. 1-5).

► InN layers stable to 630°C where significant desorption of N₂ began to occur. ► Desorption of N₂ from InN is independent of V/III growth precursor ratio. ► Activation energy for desorption of N₂ from InN measured to be 1.6±0.2eV.The thermal stability of InN layers grown on sapphire by high-pressure chemical vapor deposition has been studied by thermal desorption, atomic force microscopy, X-ray diffraction, and infrared reflection measurements. Desorption products from samples grown with group V/III precursor ratios from 1200 to 4800, but otherwise identical growth conditions, have been monitored using differentially-pumped mass spectrometry while the sample temperature was ramped from room temperature to 825°C. No significant desorption of nitrogen from the surface was observed below 630°C, with a rapid increase of desorption of molecular nitrogen at substrate temperatures above 630°C. No significant desorption of NH^*/NH₂^* fragments was observed. From Arrhenius plots, the activation energy for desorption of nitrogen was found to be 1.6±0.2eV. It was observed that the activation energy for the desorption of nitrogen from InN samples was independent of V/III precursor ratio. However, the temperature corresponding to the maximum desorption was found to be dependent on V/III precursor ratio, increasing from 749°C for V/III precursor ratio of 1200 to 776°C for V/III precursor ratio of 4800. The observed shift in the peak desorption temperature with increasing group V/III precursor ratio is attributed to the decrease in extended defects and the increase in grain size.

Keywords: Indium nitride; InN; Mass spectrometry; Desorption; Activation energy

Etching of long fiber polymeric composite materials by nanosecond laser induced water breakdown plasma by Yunfeng Cao; Yung C. Shin; R. Byron Pipes (pp. 6-10).

► Water breakdown plasma was proposed to etch a carbon fiber reinforced composite sample. ► Polymer layer can be effectively removed without damaging the carbon fiber. ► Dependence of the etching depth on laser parameters was shown. ► Maximum etching depth is around 350μm with 50 laser shots.Composite materials are widely used in industry due to their superior material properties and light weight. However, shear failure can occur at the interface between the fibers and polymer matrix when a tensile force stretches the matrix more than the fibers. Repairing the damaged composite material appears to be cost effective but still remains a challenge despite extensive research. Laser induced water breakdown plasma, which is generated by the strong interaction between nanosecond laser and water, is proposed in this work to etch the surface layer of a carbon fiber reinforced composite sample. It is found that the polymer layer can be effectively removed by the plasma while the carbon fiber remains almost intact. The dependence of the etching depth on the laser power density, laser focus position, and the number of shots are also investigated in this work. The maximum possible etching depth is around 350μm with 50 laser shots at laser power density of 70GW/cm².

Keywords: Carbon fiber; Plasma etching; Thermal analysis; Surface treatments; Laser processing

Etching of long fiber polymeric composite materials by nanosecond laser induced water breakdown plasma by Yunfeng Cao; Yung C. Shin; R. Byron Pipes (pp. 6-10).

Keywords: Carbon fiber; Plasma etching; Thermal analysis; Surface treatments; Laser processing

Growth of carbon structured over Pd, Pt and Ni: A comparative DFT study by Matías Abel Quiroga (pp. 11-15).

► We found that the graphene layer tends to grow parallel to Pd and Ni surfaces. ► We modeled a graphene monolayer (G) adsorbed over the three metals surfaces with a small mismatch. ► By using DOS and band structure analysis we can appreciate a clear metallic behavior for the three systems.To elucidate the graphene-like structures mechanisms growth over the M(111) surface (M=Pd, Pt and Ni) we performed ab initio calculus in the frame of density functional theory with the exchange-correlation functional treated according to the Generalized Gradient Approximation (GGA). In order to avoid the problem that represent the complex interaction between the well formed graphene layer and the metallic surface, we recreate the carbon rings formation initial steps, by adding one by one carbon atoms over M(111) surface. With this strategy, the chemical bonding is always present until the graphene layer is well formed, in which case the GGA neglects van der Waals dispersive forces. We investigate the electronic properties by studying the band structure and the density of states.

Keywords: Graphene; DFT; Pd; Ni; Pt

Growth of carbon structured over Pd, Pt and Ni: A comparative DFT study by Matías Abel Quiroga (pp. 11-15).

Keywords: Graphene; DFT; Pd; Ni; Pt

Initial stages of the adsorption of Sc and ScN thin films on GaN(0001): First principles calculations by J. Guerrero-Sánchez; Gregorio H. Cocoletzi; J.F. Rivas-Silva; Noboru Takeuchi (pp. 16-21).

► Studies of the initial stages in the formation of Sc and ScN structures on GaN. ► In the adsorption of Sc on the GaN the T4 site is the most stable geometry. ► When a Sc replaces a Ga of the first monolayer the displaced Ga occupies a T4 site. ► For a full monolayer of Sc there is formation of ScN in the wurtzite phase.Using first principles total energy calculations we have investigated the initial stages of the adsorption of Sc and ScN thin films on GaN(0001) surfaces under both N and Ga rich conditions. In an ideally GaN(0001) bulk terminated surface, and when the Sc atom is constrained to remain on top of the surface, the T4 site configuration is the most favorable. However a structure in which the Sc atom replaces a Ga atom of the first monolayer and the displaced Ga atom occupies a T4 site (forming bonds with Ga atoms only) has the lowest energy. Results are similar for Ga rich conditions: if the Sc atom is constrained on top of the surface, it occupies the T4 site. However, if it is allowed, it will occupy sites in the third (from top) Ga layer and it will form ScN. For a full monolayer of Sc atoms, three different configurations are possible, in all of them there is formation of scandium nitride: a ScN bilayer terminated configuration for N rich conditions, a ScN bilayer underneath a Ga bilayer for Ga rich conditions, and a ScN bilayer under a Ga layer for intermediate configurations. In all three geometries, the ScN are in wurtzite like configurations with distorted bond angles and the surfaces are metallic.

Keywords: Gallium nitride; Scandium nitride; Growth; Adsorption; Surfaces

Initial stages of the adsorption of Sc and ScN thin films on GaN(0001): First principles calculations by J. Guerrero-Sánchez; Gregorio H. Cocoletzi; J.F. Rivas-Silva; Noboru Takeuchi (pp. 16-21).

Keywords: Gallium nitride; Scandium nitride; Growth; Adsorption; Surfaces

Effects of selenization parameters on growth characteristics of the Cu(In,Ga)Se₂ films deposited by sputtering with a Cu-In-Ga, Cu-In-Ga₂Se₃, or Cu-Ga-In₂Se₃ target and a subsequent selenization procedure at 550–700°C by Dong-Hau Kuo; Yung-Chin Tu; Mehrdad Monsefi (pp. 22-27).

► Cu(In,Ga)Se₂ films obtained from different targets were compared. ► The three kinds of targets for CIGSe were Cu-In-Ga, Cu-In-Ga₂Se₃, or Cu-Ga-Se₂Se₃. ► No reports had studied the selenization above 600°C due to vaporization problem. ► The selenization problems were presented and selenization mechanism was proposed. ► Our CIGSe film selenized at 650°C was dense and had singe-grain thickness of 1.5–3μm.Cu(In,Ga)Se₂ (CIGSe) thin films were prepared by sputtering with a Cu-In-Ga, Cu-In-Ga₂Se₃, or Cu-Ga-Se₂Se₃ target and a subsequent selenization procedure at 550–700°C. The utilization of In₂Se₃ is to avoid the pre-matured formation of CuInSe₂, which form easily during selenization when metallic In exists in an as-deposited film. CIGSe films prepared with a Cu-Ga-In₂Se₃ target had shown the composition uniformity. The variations of microstructure, structure, and electrical properties with selenization temperature for films deposited by a Cu-Ga-In₂Se₃ target were investigated under a one-step or two-step selenization procedure. Selenization mechanism was proposed and its problems were presented. The influence of crystallinity and thin film microstructure on performance of electrical properties were investigated. CIGSe films sputtered by a Cu-Ga-In₂Se₃ target after two-step selenization at 600°C showed a good microstructure and high mobility of 106cm²V⁻¹s⁻¹, avoided a two-layer structure formation in the CIGSe film, and obtain a better crystallinity because of high solute solubility in the selenium solution during a selenization procedure.

Keywords: Cu(In,Ga)Se; ₂; Thin-film solar cells; Sputtering; Selenization

Enhancement of polycarbonate membrane permeability due to plasma polymerization precursors by Dilek Çökeliler (pp. 28-36).

► We modify surface of track-etched polycarbonate membranes by plasma polymerization technique with monomers seperately; acrylic acid and allylamine. ► We examine changes in the level of permeations on membranes after modifications. ► To use of acrylic acid as precursor decrease diffusion of target molecule on membrane. ► To use of allylamine as precursor increase diffusion of target molecule on membrane ► Plasma modification could be new approach for filtration with the selection of monomer in process depend on target species is the key idea.The diffusivity of different species through a membrane depends on several factors to illustrate the structure of the matrix, molecular size and concentration of the species and temperature. This study concerns the use of the low-pressure plasma process with different monomers to confer surface chemical character to polycarbonate membranes without altering their bulk properties for change membrane permeability. Track-etched polycarbonate membranes with 0.03μm pore sizes were modified by plasma polymerization technique with two precursors; acrylic acid and allylamine in radio frequency discharge at certain plasma process conditions (discharge power: 20W, exposure time: 10min, frequency: 13.56MHz). The transport properties of model organic acid (citric acid) was studied through unmodified and modified polycarbonate membranes by using diffusion cell system. Such plasma treated membranes were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy and surface energy changes were studied by static contact angle measurements. These results showed that the change of surface properties could be used to improve the transport properties of the target substrates. The diffusion of citric acid through plasma treated polycarbonate membrane was increased about 54.1±3.5% with precursor: allylamine while it was decreased 48.7±2.5% with precursor acrylic acid. It was observed that the presences of proper functional group (like amino) in surfaces of pores can raise the affinity to citric acid and improve its transport rate.

Keywords: Plasma polymerization; Polycarbonate membrane; Permeability; Allyamine

Enhancement of polycarbonate membrane permeability due to plasma polymerization precursors by Dilek Çökeliler (pp. 28-36).

Keywords: Plasma polymerization; Polycarbonate membrane; Permeability; Allyamine

Comparative study of ZnO nanorods and thin films for chemical and biosensing applications and the development of ZnO nanorods based potentiometric strontium ion sensor by K. Khun; Z.H. Ibupoto; C.O. Chey; Jun. Lu; O. Nur; M. Willander (pp. 37-43).

► We have grown ZnO nanorods and thin films on the gold coated glass electrode. ► The fabricated ZnO nanorods and thin films exhibited good crystal quality. ► The comparative study of chemical sensing of ZnO nanorods and thin films was done. ► The ZnO nanorods have shown the higher sensitivity and lower limit of detection for the analyte.In this study, the comparative study of ZnO nanorods and ZnO thin films were performed regarding the chemical and biosensing properties and also ZnO nanorods based strontium ion sensor is proposed. ZnO nanorods were grown on gold coated glass substrates by the hydrothermal growth method and the ZnO thin films were deposited by electro deposition technique. ZnO nanorods and thin films were characterised by field emission electron microscopy [FESEM] and X-ray diffraction [XRD] techniques and this study has shown that the grown nanostructures are highly dense, uniform and exhibited good crystal quality. Moreover, transmission electron microscopy [TEM] was used to investigate the quality of ZnO thin film and we observed that ZnO thin film was comprised of nano clusters. ZnO nanorods and thin films were functionalised with selective strontium ionophore salicylaldehyde thiosemicarbazone [ST] membrane, galactose oxidase, and lactate oxidase for the detection of strontium ion, galactose andl-lactic acid, respectively. The electrochemical response of both ZnO nanorods and thin films sensor devices was measured by using the potentiometric method. The strontium ion sensor has exhibited good characteristics with a sensitivity of 28.65±0.52mV/decade, for a wide range of concentrations from 1.00×10⁻⁶ to 5.00×10⁻²M, selectivity, reproducibility, stability and fast response time of 10.00s. The proposed strontium ion sensor was used as indicator electrode in the potentiometric titration of strontium ion versus ethylenediamine tetra acetic acid [EDTA]. This comparative study has shown that ZnO nanorods possessed better performance with high sensitivity and low limit of detection due to high surface area to volume ratio as compared to the flat surface of ZnO thin films.

Keywords: ZnO nanorods; ZnO thin film; Immobilisation; Galactose oxidase; Lactate oxidase; Strontium ionophore; Potentiometric technique

Effect of nanotube diameters on bioactivity of a multifunctional titanium alloy by Y.Q. Hao; S.J. Li; Y.L. Hao; Y.K. Zhao; H.J. Ai (pp. 44-51).

► Amorphous nanotubes of Ti–24Nb–4Zr–8Sn alloy prepared on by anodic oxidation. ► Their outer diameters controlled as 30, 50, 70 and 90nm. ► Investigation of biological behavior of MG-63 osteoblasts in response to diameters. ► The 30 and 90nm groups have the highest and the lowest cell viability respectively. ► The polished pure Ti and Ti–24Nb–4Zr–8Sn alloy have identical cell response.Ti–24Nb–4Zr–8Sn (abbreviated as Ti2448) is a multifunctional β type titanium alloy consisting of nontoxic alloying elements and possessing better balanced biomechanical properties of high strength and low elastic modulus. To improve its bioactivity, the anodic oxidation of Ti2448 alloy in neutral electrolyte containing small amounts of NH₄F was applied to produce the nanotubes consisting of the amorphous mixed oxides of TiO₂, Nb₂O₅, SnO₂ and ZrO₂. The in vitro studies of the oestoblast-like MG-63 cells were performed to evaluate the biological behavior of the nanotubes with the outer diameters of 30, 50, 70 and 90nm in comparison with the polished pure titanium and Ti2448 alloy. The results showed that the smaller diameter of 30nm promoted the cell adhesion, proliferation and differentiation whereas the larger diameter of 90nm had the worst cell viability with small spreading area of cytoskeletal actin. Although the nanotubes of Ti2448 alloy consist of the amorphous mixed oxides, it exhibits similar biological behavior with that of the amorphous TiO₂ of pure titanium. This suggests that the topography of the amorphous nanotube plays important role on cell response. Additionally, the studies did not detect statistical difference of the bioactivity for the polished pure titanium and Ti2448 alloy.

Keywords: Anodic oxidation; Nanotube; Bioactivity; Multifunctional titanium alloy

Effect of nanotube diameters on bioactivity of a multifunctional titanium alloy by Y.Q. Hao; S.J. Li; Y.L. Hao; Y.K. Zhao; H.J. Ai (pp. 44-51).

Keywords: Anodic oxidation; Nanotube; Bioactivity; Multifunctional titanium alloy

Measurement and modelling of the wettability of graphite by a silver–tin (Ag–Sn) liquid alloy by Zoltán Weltsch; Antal Lovas; János Takács; Ágnes Cziráki; Attila Toth; George Kaptay (pp. 52-60).

► We measure wettability of graphite by silver–tin (Ag–Sn) alloy. ► The system is found non-wetting, without dissolution or chemical interaction. ► The Butler equation is extended for the concentration dependence of contact angle. ► Reasonable agreement between experiment and theory is found.The wettability of graphite by the silver–tin (Ag–Sn) liquid alloy was measured using the sessile drop method at a temperature interval of 1273–1473K. The system is found poorly wetting with the contact angle at an interval of 125…142°. The contact angle passed through an elongated maximum as function of composition and increased with temperature. It was shown that no dissolution or chemical reaction takes place in the system up to 1473K. The Butler equation was extended to calculate the concentration dependence of surface tension, solid/liquid interfacial energy and that of the contact angle theoretically. The theoretical results reasonably reproduce the measured values.

Keywords: Wetting; Contact angle; Modeling; Butler equation; Graphite; Ag–Sn liquid alloy

Stability of carbon fiber surface functionality at elevated temperatures and its influence on interfacial adhesion by F. Vautard; H. Grappe; S. Ozcan (pp. 61-72).

► Thermo-chemical surface treatment and heat in inert atmosphere. ► Evolution of the elemental composition. ► Evolution of the fitting of the C(1s), O(1s) and N(1s) peaks. ► Influence on interfacial adhesion.The thermal stability of the surface chemistry of a surface treated carbon fiber, from room temperature to 1000°C, was investigated by X-ray photoelectron spectroscopy. Within a range of temperatures from room temperature to 400°C, the only surface functionalities that decomposed were carboxylic acids and dangling nitrogen containing functionalities like amines, amides or nitriles. Significant amounts of water were desorbed as well. This study enabled the testing of the coherence of the fitting of the C(1s), O(1s) and N(1s) peaks. Particularly, when considering the fitting of in the O(1s) peak, carboxylic acids were shown to be included in a single component peak centered at a binding energy of 532.1eV. The reaction of the carbon fiber surface and an acrylate resin at high temperature, because of the decomposition of carboxylic acids, was highlighted by differential scanning calorimetry. The thermal history of the composite material during its manufacture appeared to be a major influence on the nature of the interactions generated at the fiber–matrix interface and the resulting mechanical properties.

Keywords: Carbon fiber; Surface chemistry; Surface functionalization; Thermal stability; Interfacial adhesion

Stability of carbon fiber surface functionality at elevated temperatures and its influence on interfacial adhesion by F. Vautard; H. Grappe; S. Ozcan (pp. 61-72).

Keywords: Carbon fiber; Surface chemistry; Surface functionalization; Thermal stability; Interfacial adhesion

Improving endothelialization on 316L stainless steel through wettability controllable coating by sol–gel technology by Mingqi Wang; Yao Wang; Yijie Chen; Hongchen Gu (pp. 73-78).

In this study, wettability controllable coatings on 316L were obtained through sol–gel process. Through adhesion and proliferation assay of vascular endothelial cells (EC) and smooth muscle cells (SMC) on modified surfaces, accelerated endothelialization was found at the moderately hydrophilic surface (contact angle 45.3°. Such a coating displayed effective inhibition of SMC while negligible influence on EC. These results were expected to lay foundation for the solution of the vascular restenosis which was mainly derived from the hyperplasia of SMC.Display Omitted► Our current work highlights the enhancing of endothelialization of 316L by controlling the wettabilities of surface. ► Endothelial cells and smooth muscle cells responded differently to the coated surfaces. ► Accelerated endothelialization was found at the moderately hydrophilic surface. ► These results are expected to lay foundation for the solution of the vascular restenosis.Rapid endothelialization by surface coverage is considered as a way to increase blood compatibility of the vascular stent and reduce smooth muscle cell (SMC) mediated restenosis. Coatings on 316L stainless steels with different wettabilities and similar topographies were obtained through sol–gel process by regulating the proportions of tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES). Adhesion and proliferation of vascular endothelial cells (EC) and SMC on these substrates have been evaluated by cell numbers, cell morphology, and expression of cytoskeletal protein. Results showed that EC and SMC responded differently to the coated surfaces. Enhanced endothelialization of bare 316L was found at the moderately hydrophilic coating (contact angle 45.3°) which exhibited effective inhibition of SMC and negligible influence on EC. These results are expected to lay foundation for the solution of the vascular restenosis which was mainly derived from the hyperplasia of SMC.

Keywords: Stent; Sol–gel preparation; Wettability; Endothelialization; Adhesion

Improving endothelialization on 316L stainless steel through wettability controllable coating by sol–gel technology by Mingqi Wang; Yao Wang; Yijie Chen; Hongchen Gu (pp. 73-78).

Keywords: Stent; Sol–gel preparation; Wettability; Endothelialization; Adhesion

Influence of surface wettability on the tribological properties of laser textured Co–Cr–Mo alloy in aqueous bovine serum albumin solution by Liguo Qin; Ping Lin; Yali Zhang; Guangneng Dong; Qunfeng Zeng (pp. 79-86).

► Surfaces ranging from CA=21.5° to CA=142.2° were obtained by LST and FAS. ► The surface with circle dimples shows the most stable wettability. ► Wetting stability can be used as a criterion for the tribological properties. ► The textured wetting stability surface has well wear-resistance behaviors.Surface wettability behaviors of three kinds of laser textured Co–Cr–Mo alloy surfaces (arrays of circular, triangular and square shape dimples) were evaluated in aqueous bovine serum albumin (BSA) solution. The tribological properties of laser textured Co–Cr–Mo alloy were investigated by pin–on–disc reciprocating tribometer under BSA lubrication. The wetting surfaces ranging from superhydrophilic (CA=21.5°) to superhydrophobic (CA=142.2°) were obtained by dual/combined surface modification including laser surface texturing (LST) and further fluoro-alkyl silane (FAS). It was found that surface wettability behaviors of Co–Cr–Mo alloy surfaces were closely related to their tribological behaviors in BSA solution. Results showed that the contact angle of circular dimple was the most stable, sliding time of the friction pair reaching steady state stage was shortest and coefficient of friction was minimum among three regular layout shapes of dimples during the tribological tests. It suggests that the combined surface modification of LST and FAS is a promising method to improve the tribological performances and prolong the service life of Co–Cr–Mo orthopedic implants.

Keywords: Co–Cr–Mo alloy; Laser surface texture; Wettability; Tribological properties; BSA solution

Stability and electronic properties of polar and non-polar surfaces of CuI by Jiajie Zhu; Mu Gu; Ravindra Pandey (pp. 87-91).

► We predict the instability of the Cu-terminated (111) surface. ► The I-terminated surfaces are predicted to be energetically preferred. ► A blue shift of the band gap is predicted for the (110) surface.The structural and electronic properties of polar and non-polar surfaces of CuI are investigated at the GGA-DFT level of theory. The results find that the stability of the surfaces is directly related to the interplanar distance as well as the atomic character of the terminating layer. The I-terminated surfaces are predicted to be energetically preferred. We predict the instability of the Cu-terminated (111) surface, whereas the nonpolar (110) surface shows a significant surface reconstruction with a large layer rotation angle. The Cu-terminated and I-terminated(1¯1¯1¯) surfaces prefer to retain their bulk-like configurations, whereas the Cu-terminated (001) and(001¯) surfaces show large deviations from their bulk configurations. The calculated band gap shows a blue or red shift of the absorption edge relative to the bulk CuI depending on the atomic nature of the terminating surface.

Keywords: CuI; Surfaces; Stability; Electronic properties

Stability and electronic properties of polar and non-polar surfaces of CuI by Jiajie Zhu; Mu Gu; Ravindra Pandey (pp. 87-91).

Keywords: CuI; Surfaces; Stability; Electronic properties

Structure and properties of silk grafted with acrylate fluoride monomers by ATRP by Shiwei Li; Tieling Xing; Zhanxiong Li; Guoqiang Chen (pp. 92-97).

► The water repellence silk material was prepared. ► The water repellence silk was prepared through ATRP method. ► The growing of fluorine containing carbon chain affect the water repellence property of silk fabric. ► The wearability of grafted silk fabric was little affected.In order to develop water repellence silk materials, silk was grafted using acrylate fluoride monomers via atom transfer radical polymerization (ATRP) method. Scanning electron microscopy (SEM) photos of the grafted silks showed significant difference from the untreated silk. FT-IR characterization of the modified silk substrate indicated that acrylate fluoride monomers were successfully grafted onto silk surface. Differential scanning calorimetry (DSC) curves indicated that the thermal stability of the grafted silk was improved. The whiteness, breaking strength, elongation at break and air permeability of the grafted silk fabrics decreased slightly compared with the control sample. Surface contact angle test and water repellency rating test showed that the water repellence of the modified silk fabrics were better than the untreated silk. Functional silk fabric with good water repellence property could be obtained by properly controlling the grafting yield, which had little effect on the intrinsic properties of silk fabric.

Keywords: Silk fiber; ATRP; Grafting; Acrylate fluoride; Water repellence; Structure; Properties

Structure and properties of silk grafted with acrylate fluoride monomers by ATRP by Shiwei Li; Tieling Xing; Zhanxiong Li; Guoqiang Chen (pp. 92-97).

Keywords: Silk fiber; ATRP; Grafting; Acrylate fluoride; Water repellence; Structure; Properties

Helium atom diffraction study of low coverage phases of decanethiol self-assembled monolayers prepared by supersonic molecular beam deposition by E. Albayrak; S. Duman; G. Bracco; M.F. Danışman (pp. 98-102).

► Decanethiol self-assembled monolayers were grown on Au(111) by using supersonic molecular beam deposition. ► Low coverages striped phases were studied. ► Coverage was determined by monitoring helium specular reflection intensity. ► Different physisorbed states with energies ranging from 0.42eV to 0.74eV were observed. ► Two chemisorbed states with energies of 1.31eV and 1.53eV were observed.Thiol self-assembled monolayers (SAMs) on gold surfaces have a wide range of applications including surface patterning and metal contact–organic semiconductor interface modification in organic electronic devices. Here we present our studies about the low coverage phases of decanethiol (CH₃(CH₂)₉SH) SAMs on Au(111) surface, grown in vacuum by supersonic molecular beam deposition. Crystal structures, phase behaviors and desorption energies of these films determined by helium atom diffraction technique are discussed.

Keywords: Decanethiol; Self-assembled monolayers; Helium diffraction; Supersonic molecular beam deposition; Au(1; 1; 1) surface

► Decanethiol self-assembled monolayers were grown on Au(111) by using supersonic molecular beam deposition. ► Low coverages striped phases were studied. ► Coverage was determined by monitoring helium specular reflection intensity. ► Different physisorbed states with energies ranging from 0.42eV to 0.74eV were observed. ► Two chemisorbed states with energies of 1.30±0.02eV and 1.45±0.05eV were observed.Thiol self-assembled monolayers (SAMs) on gold surfaces have a wide range of applications including surface patterning and metal contact–organic semiconductor interface modification in organic electronic devices. Here we present our studies about the low coverage phases of decanethiol (CH₃(CH₂)₉SH) SAMs on Au(111) surface, grown in vacuum by supersonic molecular beam deposition. Crystal structures, phase behaviors and desorption energies of these films determined by helium atom diffraction technique are discussed.

Keywords: Decanethiol; Self-assembled monolayers; Helium diffraction; Supersonic molecular beam deposition; Au(1; 1; 1) surface

Hot corrosion behaviour of a Ni+CrAlYSiN composite coating in Na₂SO₄–25wt.% NaCl melt by Lijuan Zhu; Shenglong Zhu; Fuhui Wang (pp. 103-110).

► The Ni+CrAlYSiN and NiCrAlYSi coatings improved the hot corrosion resistance of K438. ► An oxide scale composed of α-Al₂O₃, Cr₂O₃, NiCr₂O₄ formed on the Ni+CrAlYSiN coating. ► No spallation or crack of the oxide scales on the Ni+CrAlYSiN coating was observed. ► A α-Al₂O₃ scale was formed on the NiCrAlYSi coating. ► Internal oxidation and sulphidation were detected in the NiCrAlYSi coating.Ni+CrAlYSiN nanocrystalline composite coatings and NiCrAlYSi reference coatings were prepared by vacuum arc evaporation on the Ni-based K438 superalloy. The aim of this work is to identify the hot corrosion resistance of the Ni+CrAlYSiN nanocrystalline composite coatings and the NiCrAlYSi coatings. The hot corrosion tests were carried out in a molten salt (75wt.% Na₂SO₄+25wt.% NaCl) environment at 900°C. X-Ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray spectrometer (EDX) and electron probe microanalysis (EPMA) technique were employed to characterize the coatings and the corrosion scales. The results indicated that both coatings improved the hot corrosion resistance of K438 in the molten salt environment. For the composite coating, the oxide scales were composed of α-Al₂O₃, Cr₂O₃ and minor NiCr₂O₄. No spallation or crack of the oxide scales was observed. Internal oxidation was detected in the outer part of the coating after 100h corrosion. Internal TiN and AlN formation in the substrate was detected. In contrast, obvious crack/spallation of α-Al₂O₃ oxide scales on the NiCrAlYSi coating was observed; internal oxidation and sulphidation in the coating and even in the substrate were detected.

Keywords: Superalloys; AlN; CrN; Composite coating; Hot corrosion

Hot corrosion behaviour of a Ni+CrAlYSiN composite coating in Na₂SO₄–25wt.% NaCl melt by Lijuan Zhu; Shenglong Zhu; Fuhui Wang (pp. 103-110).

Keywords: Superalloys; AlN; CrN; Composite coating; Hot corrosion

Observation on the Interface of α-Al₂O₃/Cr₂O₃: Prepared by oxidation of Al₄₅Cr₇ by Jun Cai; Bajin Xu; Guoping Ling (pp. 111-116).

► α-Al₂O₃ film was prepared by oxidation of Al₄₅Cr₇. ► Cr₂O₃ was found to be the nuclei core of α-Al₂O₃. The nucleation and growth of α-Al₂O₃ on Cr₂O₃ surface was observed and discussed. ► The interface of α-Al₂O₃/Cr₂O₃ was found to be (001)α-Al₂O₃/(001)Cr₂O₃ when α-Al₂O₃ nucleate on a fresh Cr₂O₃ facet. ► The influence of temperature for the formation and growth of α-Al₂O₃ on Cr₂O₃ surface was investigated.To explore the effects of Cr₂O₃ on the nucleation of α-Al₂O₃ and the nucleation interface of α-Al₂O₃/Cr₂O₃, the oxidation of Al₄₅Cr₇ powder at 650–720°C for 9–500h in air was carried out in this paper. The morphologies and structures of oxidized powder were investigated by XRD, SEM and TEM. The results showed that Cr₂O₃ formed at the outset of the oxidation, and acted as the nucleus of α-Al₂O₃ immediately. Then the oxidation of Al at the interface of Cr₂O₃/Al₄₅Cr₇ occurred, resulting the direct nucleation of α-Al₂O₃ on (001) facet of Cr₂O₃. The interface of α-Al₂O₃/Cr₂O₃ was found to be (001)α-Al₂O₃/(001)Cr₂O₃, with an angle about 5 degree between them. Besides, the effects of temperature on the nucleation of α-Al₂O₃ were also studied.

Keywords: Interface; α-Al; ₂; O; ₃; Cr; ₂; O; ₃; Al; ₄₅; Cr; ₇; Oxidation

Observation on the Interface of α-Al₂O₃/Cr₂O₃: Prepared by oxidation of Al₄₅Cr₇ by Jun Cai; Bajin Xu; Guoping Ling (pp. 111-116).

Keywords: Interface; α-Al; ₂; O; ₃; Cr; ₂; O; ₃; Al; ₄₅; Cr; ₇; Oxidation

High-resolution photoelectron spectroscopy study of degradation of rubber-to-brass adhesion by thermal aging by Kenichi Ozawa; Takashi Kakubo; Katsunori Shimizu; Naoya Amino; Kazuhiko Mase; Yudai Izumi; Takayuki Muro; Takayuki Komatsu (pp. 117-123).

Display Omitted► Influence of thermal aging on rubber-to-brass adhesion is investigated by chemical state analysis. ► Adhesion strength is reduced by thermal aging. ► The reduction of the Cu₂S/CuS ratio and the increase in ZnO, Zn(OH)₂ and ZnS in the adhesion layer are the characteristic changes induced by thermal aging. ► The aging process is stimulated by water in the surrounding environment.High resolution photoelectron spectroscopy is utilized to investigate degradation of rubber-to-brass adhesion by thermal aging. Special attention is given to the role of water in the environment surrounding brass-embedded rubber so that three aging processes are employed; hydrothermal aging, moist-heat aging and dry-heat aging. All aging processes lead to the decrease in the amount of S at the rubber/brass interface. This desulfurization accompanies the decrease in the ratio of Cu_xS ( x≃2) to CuS, i.e., Cu_xS/CuS, and the increase in the amount of ZnO, Zn(OH)₂ and ZnS, all of which are key factors for degradation of adhesion. The changes in the chemical composition are enhanced by water in the surrounding environment during the aging treatments, indicating that the water molecules accelerate degradation of rubber-to-brass adhesion.

Keywords: Photoelectron spectroscopy; Rubber; Brass; Adhesion; Thermal aging

Capture of carbon dioxide from flue gases by amine-functionalized TiO₂ nanotubes by Fujiao Song; Yunxia Zhao; Yan Cao; Jie Ding; Yunfei Bu; Qin Zhong (pp. 124-128).

The novel CO₂ adsorbents were prepared through impregnating the as-synthesized TiO₂ nanotubes with four kinds of amines. CO₂ capture was investigated in a dynamic packed column. TiO₂ nanotubes impregnated by TEPA show superior adsorption properties.Display Omitted► TiO₂ nanotubes were synthesized via hydrothermal treatment. ► The novel CO₂ adsorbents were prepared through impregnating the as-synthesized TiO₂ nanotubes with four kinds of amines. ► CO₂ capture was investigated in a dynamic packed column. ► TiO₂ nanotubes impregnated by TEPA show superior adsorption capacity and excellent CO₂ adsorption/desorption performance. ► The synthesis way of the adsorbents not only saves energy but also is environmentally friendly.The novel carbon dioxide (CO₂) adsorbents with high capture efficiency were prepared through impregnating TiO₂ nanotubes (TiNT) with four kinds of amines, namely monoethanolamine (MEA), ethylenediamine (EDA), triethylenetetramine (TETA) and tetraethylenepentamine (TEPA), respectively. The samples were characterized by thermogravimetric analysis, low temperature N₂ adsorption and transmission electron microscopy. CO₂ capture was investigated in a dynamic packed column. The TEPA-loaded sample showed a better adsorption capacity due to its higher amino-groups content. In condition, TiNT-TEPA-69 shows the highest CO₂ adsorption capacity among the four TEPA-loaded samples, approximately 4.37mmol/g at 60°C. The adsorption capacity was enhanced to 5.24mmol/g under moisture conditions. TiNT-TEPA-69 was selected as adsorbent to study the adsorption/desorption behavior in the absence of moisture and in the presence of moisture. While the former is fairly stable after 5 adsorption/desorption cycles, the latter decreases dramatically.

Keywords: TiO; ₂; nanotubes; Amine-loaded; Gas separation; Moisture; CO; ₂; adsorption

Capture of carbon dioxide from flue gases by amine-functionalized TiO₂ nanotubes by Fujiao Song; Yunxia Zhao; Yan Cao; Jie Ding; Yunfei Bu; Qin Zhong (pp. 124-128).

Keywords: TiO; ₂; nanotubes; Amine-loaded; Gas separation; Moisture; CO; ₂; adsorption

Enhanced visible light photocatalytic activity of Bi₂WO₆ via modification with polypyrrole by Fang Duan; Qianhong Zhang; Dongjian Shi; Mingqing Chen (pp. 129-135).

► Novel PPy/Bi₂WO₆ composite photocatalysts were synthesized by ‘in-situ’ deposition oxidative polymerization of pyrrole. ► PPy on the surface of Bi₂WO₆ could narrow the band gap and inhibit the recombination of holes and electrons. ► PPy showed great influences on improving the photocatalytic activity of Bi₂WO₆. ► The mechanism for enhanced photocatalytic activity of PPy/Bi₂WO₆ photocatalyst was discussed.Enhanced visible light photocatalytic activity of Bi₂WO₆ photocatalyst modified with different amounts of polypyrrole (PPy) was synthesized by ‘in situ’ deposition oxidative polymerization of pyrrole. The as-prepared PPy/Bi₂WO₆ composites were characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FT-IR) spectra, X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse absorption spectra. The photocatalytic activities of the PPy/Bi₂WO₆ samples were determined by photocatalytic degradation of rhodamine-B (RhB) and methylene blue (MB) in aqueous solution under visible light irradiation. The results indicated that the existence of PPy did not affect the crystal structure and the morphology of Bi₂WO₆ photocatalyst, but showed great influences on the photocatalytic activity of Bi₂WO₆. Besides, an optimal content of PPy on the surface of Bi₂WO₆ photocatalyst with the highest photocatalytic ability was discovered, and the obtained PPy/Bi₂WO₆ photocatalysts showed high stability and did not photocorrode during the photocatalytic process. The possible mechanism of enhanced photocatalytic activities of PPy/Bi₂WO₆ samples was also discussed in this work.

Keywords: PPy/Bi; ₂; WO; ₆; composite; Visible light; Photocatalytic activity

Enhanced visible light photocatalytic activity of Bi₂WO₆ via modification with polypyrrole by Fang Duan; Qianhong Zhang; Dongjian Shi; Mingqing Chen (pp. 129-135).

Keywords: PPy/Bi; ₂; WO; ₆; composite; Visible light; Photocatalytic activity

Isothermal oxidation study on NiMnGa ferromagnetic shape memory alloy at 600–1000°C by Mediha Kök; Gürsev Pirge; Yıldırım Aydoğdu (pp. 136-140).

► Oxidation behavior of NiMnGa magnetic shape memory alloy was investigated. ► Oxidation constant increased with rising isothermal temperatures. ► According to XRD, intensity of martensite phase decreased with rising isothermal temperatures. ► The oxidation eliminated shape memory effect of alloy.Oxidation behavior of NiMnGa alloy has been investigated under isothermal temperature by thermo gravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy equipped with an energy dispersive X-ray (SEM–EDX) spectroscope systems. The Ni–28.5Mn–20.5Ga alloy (composition in atomic percent) was exposed to oxygen atmosphere isothermally, i.e., between 600°C and 1000°C, for 1h. A gravimetric method was used to determine the oxidation kinetics; weight gain per unit area as a function of time. It was determined that the oxidation constant increases significantly with isothermal temperature. Activation energy of the oxidation was found to be 152kJ/mol. X-ray diffraction patterns of the heat-treated samples contain oxide peaks, mainly belonging to Mn₃O₄. X-ray analyses demonstrate that the amount of the oxide increases with isothermal temperature while that of martensite phase decreases. The scanning electron microscopy equipped with an energy dispersive X-ray (SEM–EDX) spectroscope analysis also gives the same result. According to magnetic measurements, the saturation of NiMnGa alloys decreases with rising isothermal oxidation temperature.

Keywords: Oxidation; Isothermal; NiMnGa; Mass gain; Activation energy

Isothermal oxidation study on NiMnGa ferromagnetic shape memory alloy at 600–1000°C by Mediha Kök; Gürsev Pirge; Yıldırım Aydoğdu (pp. 136-140).

Keywords: Oxidation; Isothermal; NiMnGa; Mass gain; Activation energy

Solid phase growth of NiSi in polycrystalline Si on SiO₂ with Cl plasma containing NiCl by K. Kanomata; K. Momiyama; S. Kubota; T. Suzuki; F. Hirose (pp. 141-145).

► Ni silicidation in poly Si is possible by a NiCl plasma treatment. ► The Ni and Si depth profile is uniform in the Ni silicide film. ► The Ni silicide growth depends on the plasma power and the substrate temperature. ► We discuss the growth mechanism of Ni silicide through the NiCl plasma treatment.Nickel silicidation of polycrystalline Si (poly Si) on SiO₂ is possible by treating a poly Si surface with a Cl plasma containing NiCl. This process allows the fabrication of NiSi film with a uniform concentration profile on SiO₂. The nickel silicide growth depends on the plasma power and the substrate temperature. A TEM observation indicates the presence of Si layer on the growing surface, which suggests that the surface segregation of Si might play an important role in the solid phase growth of NiSi. RBS measurements evidence that the average Ni concentration increases with the plasma treatment time, which suggests the Ni condensation by Ni deposition and selective Si etching on the growing surface. Based on the experimental results, we discuss the growth mechanism of nickel silicide prepared through the Cl plasma containing NiCl.

Keywords: Nickel silicide; Plasma; Solid phase growth

Solid phase growth of NiSi in polycrystalline Si on SiO₂ with Cl plasma containing NiCl by K. Kanomata; K. Momiyama; S. Kubota; T. Suzuki; F. Hirose (pp. 141-145).

Keywords: Nickel silicide; Plasma; Solid phase growth

Influence of Co doping on structural, optical and magnetic properties of BiFeO₃ films deposited on quartz substrates by sol–gel method by Lin Peng; Hongmei Deng; Jianjun Tian; Qing Ren; Cheng Peng; Zhipeng Huang; Pingxiong Yang; Junhao Chu (pp. 146-150).

► BiFe1−_xCo_xO₃ ( x=0, 0.03, 0.05, 0.1) thin films were firstly deposited on quartz substrates by sol–gel method. ► The optical band gap of BiFe1−_xCo_xO₃ decreases from 2.66eV to 2.53eV with the increase of Co from x=0 to 0.1. ► Co doping in BiFeO₃ provides preliminary research for optoelectronic devices and infrared detectors. ► Compared with BiFeO₃, the remanent magnetization M_r of BiFe1−_xCo_xO₃ thin films significantly enhanced.Multiferroic BiFe1−_xCo_xO₃ ( x=0, 0.03, 0.05, 0.1) thin films have been prepared on quartz substrates using a sol–gel technique. X-ray diffraction data confirms that Co atoms have been successfully incorporated into the host lattice. The scanning electron microscopy (SEM) exhibits that the surface morphologies of BiFe_0.97Co_0.03O₃ and BiFe_0.95Co_0.05O₃ thin films become more compact and uniform. With increasing Co dopant, the position of A₁-1 and E-4 modes shift towards the lower wavenumber indicates that Co doping induces structural distortion of BiFeO₃. With increasing Co composition, the fundamental absorption edges of BiFe1−_xCo_xO₃ films show red shift. Furthermore, transmittance spectra demonstrates that the optical band gap of BiFe1−_xCo_xO₃ films decreases from 2.66eV to 2.53eV with the increase of Co from x=0 to 0.1. At the wavelength of 720nm, the refractive index decreases and the extinction coefficient increases with increasing the amount of Co. Optical properties reveal that Co doping in BiFeO₃ provides preliminary research for optoelectronic devices and infrared detectors. Compared with BiFeO₃ prepared under similar conditions, the remanent magnetization M_r of BiFe1−_xCo_xO₃ ( x=0.03, 0.05, 0.1) thin films significantly enhanced, which provides potential applications in information storage.

Keywords: BiFeO; ₃; Co doping; Optical and magnetic properties

Influence of GaAs(001) pregrowth surface morphology and reconstruction on the growth of InGaAs layers by Qing Zhou; Zijiang Luo; Ke Liu; Xiang Guo; Bichan Zhang; Xun Zhou; Jihong Wang; Zhao Ding (pp. 151-155).

► In_0.15Ga_0.85As film has been deposited on different GaAs pregrowth surface by MBE. ► As coverage and roughness influence heteroepitaxial growth in the earliest stages. ► STM and RHEED patterns reflect the morphology and reconstruction of film surface.The influence of pregrowth surface morphology and reconstruction upon the growth of In_0.15Ga_0.85As alloy layers was investigated. After obtaining different pregrowth surfaces, depositions of InGaAs were carried out by molecular-beam epitaxy (MBE). The real space ultrahigh vacuum scanning tunneling microscopy (STM) images showed the disciplinary changes between GaAs and InGaAs surface morphology. Reﬂection high energy electron diffraction (RHEED) has also been used to estimate InGaAs deposition. As STM images and RHEED oscillations showed, heteroepitaxial surface quality greatly depends on initial state of surface even form the earliest stages of deposition. Two reasons of the effects are proposed, a conjecture for the formation of surfaces morphology and its influence on subsequent growth is also proposed.

Keywords: Surface processes; Scanning tunneling microscopy; Reﬂection high energy electron diffraction; Molecular beam epitaxy; Semiconducting III–V materials

Improvement of the power conversion efficiency of organic photovoltaic cells with a P3HT layer fabricated by using a sonication process and having a vertically modulated nanoscale morphology by Yong Hun Lee; Dae Hun Kim; N. Sabari Arul; Tae Whan Kim (pp. 156-162).

► OPV cells utilizing a vertically modulated nanoscale morphology using sonication process. ► Vertically modulated morphology under 15min sonication time process shows uniform morphology. ► The PCEs of the OPV cells with a P3HT layer sonicated for 15min were significantly enhanced.In organic photovoltaic (OPV) cells, the nanoscale morphology of the organic layer is an essential parameter governing their charge-transport properties. Optimization of the vertical composition gradient in the poly(3-hexylthiophene) (P3HT) active layer in an OPV cell with an enhanced efficiency was achieved by using different sonication times of 10, 15, 20, 25, and 30min. Atomic force microscopy images confirmed that the sonication process increased the roughness of the P3HT layer in a vertically modulated nanoscale morphology. Photoluminescence spectra exhibited a strong peak corresponding to the P3HT particles. The power conversion efficiency of the OPV cells with a vertically modulated P3HT nanostructural layer sonicated at 15min was enhanced by 1.04% due to an increase in the interfacial region between the acceptor and the donor materials.

Keywords: PACS; 84.60.Jt; 73.50.Pz; 68.37.Ps; 82.80Organic photovoltaic cells; P3HT; Rough structures; Power conversion efficiency; Nanoscale morphology

Competitive adsorption of Pb²⁺ and Cd²⁺ on magnetic modified sugarcane bagasse prepared by two simple steps by Jun-Xia Yu; Li-Yan Wang; Ru-An Chi; Yue-Fei Zhang; Zhi-Gao Xu; Jia Guo (pp. 163-170).

► Magnetic modified sugarcane bagasse was prepared by two simple steps. ► The magnetic sorbent had high adsorption capacity and rapid adsorption rate for Pb²⁺ and Cd²⁺. ► Pb²⁺ was favorably adsorbed onto the magnetic sorbent over Cd²⁺. ► Langmuir competitive model was suitable to predict the sorption in the binary system.Magnetic modified sugarcane bagasse with high adsorption capacity and rapid adsorption rate was prepared by two simple steps. Experimental results showed that the adsorption capacities of the magnetic sorbent for Pb²⁺ and Cd²⁺ were 1.2 and 1.1mmolg⁻¹, respectively. Pseudo-second-order and pseudo-first-order kinetic model both could predict the adsorption and desorption kinetic process occurred on the modified sorbent. EDX analysis showed that Pb²⁺ and Cd²⁺ were adsorbed on the sorbent mainly through ion exchange. Competitive adsorption results showed that the presence of Pb²⁺ exerted a great inhibitory effect on Cd²⁺ adsorption, and the inhibitory effect increased with the increase of the initial concentration ratio of Pb²⁺ and Cd²⁺ ( C₀^Pb: C₀^Cd). Pb²⁺ could be selectively adsorbed by the magnetic sorbent when the values of C₀^Pb: C₀^Cd was higher than or equal to 4:1. It was also found that Langmuir competitive model was suitable to predict the sorption isotherm in the binary system. The as prepared magnetic sorbent had a potential in heavy metal wastewater treatment.

Keywords: Sugarcane bagasse; Adsorption; Magnetic sorbent; Pb; ²⁺; Cd; ²⁺

Surface study of films formed on copper and brass at open circuit potential by R. Procaccini; W.H. Schreiner; M. Vázquez; S. Ceré (pp. 171-178).

► Oxide films formed on copper and brass were studied in borax 0.1molL⁻¹ solution. ► Voltammetries, XPS and Raman show that the film on Cu contains Cu₂O and CuO. ► In the case of brass the same corrosion products are found, together with ZnO. ► The surface products containing zinc are much more soluble than those with copper. ► Adding in Cl⁻, copper-chloride compounds incorporate to the films on both materials.The corrosion resistance of Cu–Zn alloys strongly depends on the quality of the protective passive film. This study focuses on the influence of Zn on the composition of oxide films on copper and brass (Cu77Zn21Al2) in borax 0.1molL⁻¹ (pH 9.2) solution, where the solubility of copper oxides is minimal. The effect of the presence of chloride ions at low concentration (0.01molL⁻¹) in the electrolyte was also evaluated. Both conditions were studied using a set of different electrochemical, optical and surface techniques such as cyclic voltammetry, differential reflectance, X-ray photoelectron spectroscopy and Raman spectroscopy. A duplex Cu₂O/CuO layer forms on copper at potentials positive to the open circuit potential (OCP), while in the case of brass, zinc compounds are also incorporated to the surface film. It also became evident that a surface film can be formed on these materials even at potentials negative to the OCP. Zn(II) species are the main constituents of the films growing on brass, while copper oxides are incorporated to the surface film when approaching the OCP. The presence of chloride ions at low concentrations contributes to the dissolution of the oxo-hydroxides formed during the early stages of the aging process at open circuit potential. Also, copper chloro-compounds are formed, as shown by Raman spectroscopy for both copper and brass electrodes.

Keywords: Copper alloys; Surface films; Chloride ions; XPS; Raman

Surface study of films formed on copper and brass at open circuit potential by R. Procaccini; W.H. Schreiner; M. Vázquez; S. Ceré (pp. 171-178).

Keywords: Copper alloys; Surface films; Chloride ions; XPS; Raman

Quaternary ammonium salts intercalated α-ZrP compounds for adsorption of phenolic compounds by Hongning Wang; Wenjin Liu; Wei Yao; Ke Zhang; Jing Zhong; Ruoyu Chen (pp. 179-187).

Display Omitted► Different quaternary ammonium salts intercalated α-ZrP were synthesized. ► The intercalation mechanism is proposed according to the experimental results. ► The intercalation compounds show high performance of phenolic compounds adsorption. ► Adsorption mechanism of intercalated compounds for phenols is also proposed.By using methylamine as the colloidization agent to weaken the interactions of α-ZrP laminate, the quaternary ammonium salts of DTAB, TTAB, CTAB and STAB were successfully intercalated into the methylamine pre-pillared α-ZrP, denoted as DTAB-ZrP, TTAB-ZrP, CTAB-ZrP and STAB-ZrP, respectively. XRD, FTIR, TEM and N₂ sorption were used to characterize the intercalated compounds, and the arrangements of intercalated quaternary ammonium salts within ZrP were supposed according to the results. It was shown that the interlayer distances were increased from 0.76nm to 2.10–3.50nm and the intercalated quaternary amine salt cationic bonded with PO⁻ anion through electrostatic interaction. The phenolic compounds adsorption results have demonstrated that all the four intercalated compounds have good adsorption performance, and CTAB-ZrP show the highest maximum adsorption amounts of 0.90, 1.25 and 1.34mmolg⁻¹, for phenol, 2-chlorophenol and 2,4-dichlorophenolare, respectively. The adsorption isotherms of phenolic compounds are linear with the C₀ of 2.0–6.0mmolL⁻¹ and fit well to both the Linear and the Freundlich models, which indicated that the adsorption mechanism is mainly partition effects of organic phase within ZrP interlayer.

Keywords: α-ZrP; Quaternary ammonium salt; Phenolic compounds adsorption; Partition effect

Quaternary ammonium salts intercalated α-ZrP compounds for adsorption of phenolic compounds by Hongning Wang; Wenjin Liu; Wei Yao; Ke Zhang; Jing Zhong; Ruoyu Chen (pp. 179-187).

Keywords: α-ZrP; Quaternary ammonium salt; Phenolic compounds adsorption; Partition effect

Microstructure characterization and NO₂-sensing properties of porous silicon with intermediate pore size by Mingda Li; Ming Hu; Qinglin Liu; Shuangyun Ma; Peng Sun (pp. 188-194).

Display Omitted► The porous silicon (PS) with intermediate pore size (50–200nm) was successfully prepared using electrochemical etching method without additional oxidizing agents and illumination. ► The pore morphology of PS was changed noticeably by varying the etching time. ► Optimized PS structure has a high porosity of 75% and direct excellent gas diffusion channels, exhibiting good and desirable gas-sensing properties toward sub-ppm NO₂ at room temperature. ► NO₂-sensing mechanism of PS was also discussed. ► The PS kept its gas-sensing characteristic during four weeks.In this work, a novel intermediate-size porous silicon (intermediate-PS) gas sensor was prepared successfully by electrochemical etching method. The morphology and geometry of PS samples were observed using field emission scanning electron microscope (FESEM). The surface chemical bonds were determined by Fourier transform infrared (FTIR) spectroscopy. It is found that PS showed typical n-type semiconductor behavior. Furthermore, it exhibited good response value, excellent repeatability and fast response–recovery characteristic when exposed to NO₂ gas at room temperature. Compared with other microstructures of PS, intermediate-PS showed much better gas-sensing properties because high special surface area provided more adsorption sites, and unique structural properties dramatically increased rates of gas diffusion. In addition, possible NO₂-sensing mechanisms and potential applications were also discussed.

Keywords: Porous silicon; Electrochemical etching; Intermediate size pore; NO; ₂; detection; Room temperature

Microstructure characterization and NO₂-sensing properties of porous silicon with intermediate pore size by Mingda Li; Ming Hu; Qinglin Liu; Shuangyun Ma; Peng Sun (pp. 188-194).

Keywords: Porous silicon; Electrochemical etching; Intermediate size pore; NO; ₂; detection; Room temperature

The plasma nitriding treatment of TiN/TiCN multilayer films by Jianyun Zheng; Junying Hao; Xiaoqiang Liu; Qiuyu Gong; Weimin Liu (pp. 195-203).

► TiN/TiCN multilayer films were conducted by plasma nitriding treatment. ► After plasma nitriding treatment, the film structure was changed significantly. ► The variation of the structure leaded to improve the film properties. ► The internal stresses and the hardness showed a declining trend slightly. ► The tribological behaviors of the films were improved by plasma-nitriding.The TiN/TiCN multilayer films were deposited by direct current magnetron sputtering, and then the nitriding treatments were carried out in low pressure plasma excited by single-frequency discharge mode. It could be found that the nitriding time had a considerable influence on the composition of uppermost TiCN layer. These variations mainly embodied on the decrement of the TiC bonds and the increment of the CN and TiN bonds with increasing the nitriding time. Moreover, after the 40min plasma-nitriding treatment, the TiCN layers within the films produced a mass of amorphous carbon (a-C) due to the decomposition of the supersaturated solid solution, and all TiN layers and the uppermost TiCN layer exhibited fine columnar crystals mixed with some amorphous materials. All the results were attributed to the plasma energy breaking the TiC bonds in the film surface, inducing the structure transformation and supporting the carbon diffusion within the films. In the view of the changes of the structure, the internal stresses and the hardness showed a declining trend slightly. Exhilaratingly, the tribological behaviors of the films were improved significantly by the plasma-nitriding. After 40min plasma-nitriding, the mean coefficient of friction (COF) and the wear rate of the film sliding 10h were only about 0.15 and 4.8×10⁻⁷mm³/Nm, respectively. In addition, the COF of TiN layer fell from around 0.4–0.6 in other films to around 0.15 in this film.

Keywords: Thick TiN/TiCN multilayer films; Plasma-nitriding treatment; Structure and properties; The diffusion of the amorphous C

The plasma nitriding treatment of TiN/TiCN multilayer films by Jianyun Zheng; Junying Hao; Xiaoqiang Liu; Qiuyu Gong; Weimin Liu (pp. 195-203).

Keywords: Thick TiN/TiCN multilayer films; Plasma-nitriding treatment; Structure and properties; The diffusion of the amorphous C

Enhanced photoelectric property and visible activity of nitrogen doped TiO₂ synthesized from different nitrogen dopants by Xiuwen Cheng; Xiujuan Yu; Zipeng Xing (pp. 204-208).

► N–TiO₂ photocatalysts have been synthesized from different nitrogen dopants. ► Different N dopants could result in different surface state and light absorption. ►N(NH3)–TiO2 exhibited higher photocatalytic activity than that of others. ► The relationships between photoelectric property and visible activity were discussed.N doped TiO₂ nano-particles were synthesized through simple sol–gel reactions from different nitrogen dopants. The resulting materials were characterized by X-ray diffraction (XRD), Raman spectra, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), ultraviolet–visible diffuse reflectance spectroscopy (UV–vis DRS) and surface photovoltage spectroscopy (SPS). Furthermore, the photoelectric property and activity enhanced mechanism were investigated in detail. It was found that the introduction of N dopants could effectively inhibit the crystal growth of TiO₂ nano-particles, enhance the light absorption in visible region, possess more surface hydroxyl groups and separate the photoinduced charge carriers. The effects of dopants on the photocatalytic activity for the degradation of rhodamine B (RhB) were investigated in detail. It is clearly demonstrated that the photocatalytic activity ofN(NH3)–TiO2 nano-particle was higher than that ofN(NH4Cl)–TiO2 and undoped TiO₂. The enhanced photocatalytic activity could be attributed to the smaller crystal size, more hydroxyl groups on surface of the catalyst, stronger light absorption in visible region and higher separation efficiency of photoinduced charge carriers.

Keywords: N doped TiO; ₂; Visible light; Photoelectric property; Photocatalytic activity; RhB

Enhanced photoelectric property and visible activity of nitrogen doped TiO₂ synthesized from different nitrogen dopants by Xiuwen Cheng; Xiujuan Yu; Zipeng Xing (pp. 204-208).

Keywords: N doped TiO; ₂; Visible light; Photoelectric property; Photocatalytic activity; RhB

Correlation between ZnO nanorod growth and the dislocations in AlN-based substrates by Qiu-Ming Fu; Jian-Peng Wu; Zhi-Bin Ma; Yi-Bo Han; Ya-Fang Tu (pp. 209-212).

► Selective growth of ZnO nanorods by controlling the dislocation density contained in AlN-based substrates was demonstrated. ► Correlation between ZnO nanorod growth and the dislocation density in the substrates was revealed. ► Alignment and average diameter of ZnO nanorods were found to be affected by dislocation etch pits exposed on the surface of AlN.ZnO nanorods were selectively grown on AlN-based substrates by hydrothermal synthesis without employing seed layers. The correlation between ZnO nanorod growth and the dislocation density in the substrates was revealed. Furthermore, the alignment and average diameter of ZnO nanorods were found to be affected by dislocation etch pits exposed on the surface of AlN. A red-shift in photoluminescence emission spectra of ZnO nanorods on etched-AlN was also observed, which can be attributed to the surface effect.

Keywords: Zinc oxide; Nitrides; Threading dislocations; Hydrothermal synthesis

Correlation between ZnO nanorod growth and the dislocations in AlN-based substrates by Qiu-Ming Fu; Jian-Peng Wu; Zhi-Bin Ma; Yi-Bo Han; Ya-Fang Tu (pp. 209-212).

Keywords: Zinc oxide; Nitrides; Threading dislocations; Hydrothermal synthesis

Synthesis and adsorption/photocatalysis performance of pyrite FeS₂ by Shuling Liu; Miaomiao Li; Shu Li; Honglin Li; Lu Yan (pp. 213-217).

Display Omitted► Pyrite FeS₂ crystallites were prepared by using K₄[Fe(CN)₆]·3H₂O as Fe source. ► The as-prepared pyrite FeS₂ could high-efficiently degrade organic dyes. ► The adsorption ability of the FeS₂ crystallites is much higher than their photocatalytic degradation capacity.FeS₂ crystallites were synthesized successfully via a solvothermal method, using potassium ferrocyanide K₄[Fe(CN)₆]·3H₂O as Fe source, sulfur powder as S source in the presence of polyvinyl pyrrolidone (PVP) as dispersant. And potassium carbonate provided an alkaline environment. The phase and morphology of the products were characterized by means of X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). It was found that the temperature and solvent ratio (VEtOH:VH2O) play a crucial role in the formation of FeS₂ with a cubic phase structure (pyrite). Then based on a series of experiments, the possible formation mechanism of pyrite FeS₂ crystallites was proposed. In addition, research also showed that the as-prepared pyrite FeS₂ crystallites could high-efficiently absorb or photocatalytically degrade some organic dyes such as Methylene blue (MB), Safranine T, Methyl orange (MO), Rhodamine B (Rh B) and Pyronine B. Furthermore, the adsorption and photocatalytic degradation abilities of FeS₂ for organic dyes were also compared.

Keywords: Pyrite; Solvothermal; Adsorption/photocatalysis

Synthesis and adsorption/photocatalysis performance of pyrite FeS₂ by Shuling Liu; Miaomiao Li; Shu Li; Honglin Li; Lu Yan (pp. 213-217).

Keywords: Pyrite; Solvothermal; Adsorption/photocatalysis

Optimizing structural and compositional properties of electrodeposited ceria coatings for enhanced oxidation resistance of a nickel-based superalloy by B. Bouchaud; J. Balmain; G. Bonnet; F. Pedraza (pp. 218-224).

► Modulation of composition, microstructure and thickness of electrodeposited ceria coatings. ► Role of current density on the appearance of cracks and oxygen vacancies highlighted. ► Linear mass gain with a high synthesis yield and no spallation was demonstrated. ► Formation of alpha-alumina from the γ′ phase of the substrate during annealing. ► Different crystallization microstructures depending on the temperature.Cathodic electrodeposition was used to generate ceria coatings onto a Ni-based superalloy substrate. The electrochemical parameters were optimized so as to obtain relatively thick but adherent films with tailored composition and microstructural features (multi-cracked network) designed for high temperature applications. Whereas the applied current density was shown to mainly influence the appearance and size of the cracks as well as the amount of oxygen vacancies, the linear trend between the deposited mass and the deposition time allowed a good control of the deposited thickness. A crystallization/diffusion thermal treatment was then applied to promote the dehydration of the deposit, thus resulting in a network of refined cracks, and in the complete crystallization of nanometric CeO2−_x exhibiting either a needle-like or a quasi “foam-like” microstructure depending on the applied temperature. This also provided the establishment of an inwardly grown α-Al₂O₃ scale at the substrate/coating interface expected to further increase the high temperature oxidation resistance of the coated superalloy.

Keywords: Cathodic electrodeposition; Ceria; Multi-cracked morphology; Oxygen vacancies; Crystallite size; Ni-based superalloy; High temperature oxidation

The effect of oxidation treatment by KClO₃/H₂SO₄ system on intersurface performance of carbon fibers by Linghui Meng; Dapeng Fan; Chunhua Zhang; Zaixing Jiang; Yudong Huang (pp. 225-230).

Display Omitted► Treating with this method is appropriate to reduce the strength loss of oxidation. ► Treating with this method can increase oxygen contents on carbon fiber surfaces significantly. ► Treating with this method does not harm for the dispersion force of the treated fiber surface.The polyacrylonitrile-based (PAN-based) carbon fibers with progressive amounts of the oxidation treatment have been investigated using a number of surface analytical methods. The chemical content and structure of oxidated fibers have been interrogated by X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM), then compared to the untreated ones. The value of oxygen content increased from 4.71% to 18.84%, meanwhile, the grooves on the surfaces of the carbon fibers were deepened gradually after treatments. The results of dynamic contact angle (DCA) measurements suggest that the increase in carbon fiber surface tension is mainly because of the polar component of surface tension. After treated with increasing amounts of oxidants, the monofilament tensile strength decreased less than 3.1%.

Keywords: Carbon fiber; KClO; ₃; Oxidation; Surface treatment

The effect of oxidation treatment by KClO₃/H₂SO₄ system on intersurface performance of carbon fibers by Linghui Meng; Dapeng Fan; Chunhua Zhang; Zaixing Jiang; Yudong Huang (pp. 225-230).

Keywords: Carbon fiber; KClO; ₃; Oxidation; Surface treatment

Aqueous solution-chemical derived NiAl₂O₃ solar selective absorbing coatings. 2. Wetting agents and spreading of aqueous solutions on aluminum substrate by Zhenxiang Li; Jianxi Zhao (pp. 231-236).

► The efficiency of wetting depended on the length of POE chain of the nonionic surfactants. ► The nonionic surfactants with a long POE chain were suitable as the wetting agents. ► The NiAl₂O₃ coatings containing wetting agents with long POE chain generated a high solar absorptance of 0.81.Wettability of aluminum substrate by the aqueous solutions containing ethoxylated alcohol nonionic surfactants C₁₂E_n- or Triton X-series was studied using dynamic contact angle measurements. The efficiency of wetting was found to strongly depend on the length of polyoxyethylene (POE) chain of C₁₂E_n- or Triton X surfactants. For C₁₂E₄ that has a very short POE chain, it hardly made the aqueous solution spreading over aluminum. The others with a long POE chain were indeed very efficient in promoting the solution spreading. Moreover, all the spreading process could be completed within 10s. The single-layer NiAl₂O₃ coatings were fabricated from the precursor solutions containing C₁₂E_n- or Triton X surfactants and the reflectance spectra were measured by a UV/vis spectrophotometer equipped with an integrating sphere. The results indicated that the precursor solution with a long POE chain surfactant as wetting agent favored to fabricate a uniform film on the aluminum substrate and therefore to get a high solar absorptance.

Keywords: Nonionic surfactants; Wetting and spreading; Aluminum substrate; Solar selective absorbing coatings

Fabrication and photocatalytic properties of spheres-in-spheres ZnO/ZnAl₂O₄ composite hollow microspheres by Li Zhang; Jianhui Yan; Minjie Zhou; Yahui Yang; You-Nian Liu (pp. 237-245).

► S@S-ZnO/ZnAl₂O₄ microspheres have been fabricated via one-pot hydrothermal method. ► The formation of S@S-ZnO/ZnAl₂O₄ relies on the molar ratio of glucose to metal ion. ► The coupling of the ZnO and ZnAl₂O₄ enhanced photocatalytic performance. ► S@S-ZnO/ZnAl₂O₄ microspheres show superior photocatalytic activity. ► The synthesis strategy of composite materials with complex structure may be proposed.ZnO/ZnAl₂O₄ composite hollow microspheres have been fabricated using glucose as template by a polyethylene glycol (PEG-4000)-assisted one-pot hydrothermal method. The as-prepared samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), UV–vis diffusive reflectance spectroscopy (DRS), Brunauer–Emmett–Teller (BET) measurement and X-ray photoelectron spectroscopy (XPS). The effects of the content of ZnO( X) and the molar ratio of glucose to metal ion ( R) on the structure, composition, morphology and textural properties of the as-prepared samples were investigated in detail. The results indicated that a novel spheres-in-spheres ZnO/ZnAl₂O₄ composite hollow microspheres (designated as S@S-ZnO/ZnAl₂O₄) could be obtained as X=25mol% and R=1. In addition, the photocatalytic activity of the as-prepared samples was evaluated by photocatalytic decolorization of methyl orange (MO) aqueous solution under the irradiation of the simulated sunlight (100mW/cm²). The maximum photocatalytic decoloration rate of 98.7% within 60min was obtained at 0.5gL⁻¹ concentration of S@S-ZnO/ZnAl₂O₄ photocatalyst, which exceeded that of Degussa P25 under the same conditions.

Keywords: ZnO/ZnAl; ₂; O4; Spheres-in-spheres; Composite hollow microsphere; Photocatalytic activity

Fabrication and photocatalytic properties of spheres-in-spheres ZnO/ZnAl₂O₄ composite hollow microspheres by Li Zhang; Jianhui Yan; Minjie Zhou; Yahui Yang; You-Nian Liu (pp. 237-245).

Keywords: ZnO/ZnAl; ₂; O4; Spheres-in-spheres; Composite hollow microsphere; Photocatalytic activity

Structure and redox properties of perovskite Y_0.9Sr_0.1Cr1−_xFe_xO3−_δ by Dandan Xu; Yunfei Bu; Wenyi Tan; Qin Zhong (pp. 246-251).

The Y_0.9Sr_0.1Cr1−_xFe_xO3−_δ ( x=0.1, 0.3, 0.5) was synthesized by gel combustion method. Moreover, the redox stability of Y_0.9Sr_0.1Cr1−_xFe_xO3−_δ was studied. It was found that Y_0.9Sr_0.1Cr1−_xFe_xO3−_δ was a candidate anode material for SOFC as the x=0.1.Display Omitted► Y_0.9Sr_0.1Cr1−_xFe_xO3−_δ was firstly synthesized via gel combustion method. ► Y_0.9Sr_0.1Cr1−_xFe_xO3−_δ was firstly examined as promising anode materials for SOFCs. ► Y_0.9Sr_0.1Cr_0.9Fe_0.1O3−_δ showed stability in H₂S-containing atmosphere.The aim of this paper is to examine the feasibility of Y_0.9Sr_0.1Cr1−_xFe_xO3−_δ for potential use as anode materials in solid oxide fuel cells (SOFCs) fed with fuel gas containing H₂S, as well as other electrochemical devise. Y_0.9Sr_0.1Cr1−_xFe_xO3−_δ ( x=0.1, 0.3, 0.5) were synthesized by gel combustion method and had single-phase orthorhombic perovskite structure. These materials were all stable in reducing atmosphere (10%, v/v H₂/N₂) up to 800°C. By the comparison of the O 1s peaks assigned to Y_0.9Sr_0.1Cr1−_xFe_xO3−_δ before and after reduction in H₂/N₂, lower content of lattice oxygen and higher content of adsorbed oxygen were observed for Y_0.9Sr_0.1Cr_0.9Fe_0.1O3−_δ, while others appeared opposite results. This phenomenon suggested that reduced Y_0.9Sr_0.1Cr_0.9Fe_0.1O3−_δ could capture oxygen when exposure to air, which is essential for anode materials. Moreover, Y_0.9Sr_0.1Cr_0.9Fe_0.1O3−_δ maintained good chemical stability under H₂S-containing atmosphere through XRD and FT-IR analysis. So Y_0.9Sr_0.1Cr_0.9Fe_0.1O3−_δ was suggested as a promising anode material for SOFCs fed with fuel gas containing H₂S.

Keywords: Doped yttrium chromite; Reduction stability; Hydrogen sulfide

Structure and redox properties of perovskite Y_0.9Sr_0.1Cr1−_xFe_xO3−_δ by Dandan Xu; Yunfei Bu; Wenyi Tan; Qin Zhong (pp. 246-251).

Keywords: Doped yttrium chromite; Reduction stability; Hydrogen sulfide

Enhancement of visible-light-induced photodegradation over hierarchical porous TiO₂ by nonmetal doping and water-mediated dye sensitization by Lun Pan; Ji-Jun Zou; Songbo Wang; Zhen-Feng Huang; Xiangwen Zhang; Li Wang (pp. 252-258).

Display Omitted► Combination of water-mediated dye sensitization with nonmetal doping significantly enhances the visible-light-induced photodegradation. ► Water-treated N,F-doped TiO₂ shows very high photoactivity. ► Storage environmental and period show considerable influence on photocatalytic performance of TiO₂.Dye sensitization and nonmetal doping on TiO₂ are important for visible-light utilization in many fields. In this work, N, N&S and N&F doped hierarchical macro-/mesoporous TiO₂ was prepared using hydrothermal method. Most of the nonmetals exist as surface impurities before calcination, without any visible-light response. Thermal calcination makes N effectively implanted into TiO₂ lattice and causes red shift in optical absorption, but S and F are mainly on the surface. The activity of prepared samples for the photodegradation of rhodamine B under visible light was evaluated. The reaction over doped samples without calcination proceeds solely via self-sensitization, and calcination effectively enhances the photodegradation due to nonmetal doping. After being stored for ca. half a year, the activity of all samples are promoted significantly due to the water-mediated adsorption switch from covalent to electrostatic adsorption, caused by pre-bonding of water to surface bridging hydroxyls. The activity of doped samples is further enhanced with water treatment, attributed to the formation of more water-mediated electrostatic modes. The combination of nonmetal doping and water-mediated adsorption switch greatly enhances the visible-light activity of TiO₂ (e.g., water-treated N&F-codoped sample shows 6.8-fold higher activity than pure TiO₂).

Keywords: Hierarchical TiO; ₂; Photodegradation; Dye sensitization; Nonmetal doping; Adsorption mode

Adsorption of chitosan on BN nanotubes: A DFT investigation by A. Rodríguez Juárez; E. Chigo Anota; H. Hernández Cocoletzi; A. Flores Riveros (pp. 259-264).

► Introducing the interaction between BN nanotubes with chitosan using DFT. ► Chemisorption modifying the semiconductor character of the nanotube to semimetallic. ► (5,5) BN nanotube changes its polarity to interaction with chitosan.The adsorption of the biopolymer chitosan on the (5,0) and (5,5) boron nitride nanotubes (BNNTs) was theoretically analyzed by Molecular Simulations. The calculations were done using the well known density-functional theory within the local density approximation; the exchange-correlation term was modeled with the Perdew-Wang parameterization. The structural stability was based on the obtention of the minimum energy and non-complex vibrational frequencies. Different sites, charge (neutral, cation and anion) and orientations of chitosan, using the monomer unit, were considered. For the (5,5) nanotube, the minimum energy site corresponds to that when the monomer (for all charges assigned) is perpendicular to the nanotube; only structural stability was found in the anion assignment for the (5,0) nanotube. The chemisorption process is through the amine group modifying the semiconductor character of the nanotube to semimetallic one, with ionic properties, suggesting their solubilization on hydrophilic nanomaterials.

Keywords: BN nanotubes; Amine group; Chitosan; DFT theory

Adsorption of chitosan on BN nanotubes: A DFT investigation by A. Rodríguez Juárez; E. Chigo Anota; H. Hernández Cocoletzi; A. Flores Riveros (pp. 259-264).

Keywords: BN nanotubes; Amine group; Chitosan; DFT theory

Synthesis of well-adhered SiO₂–Al₂O₃ glass-ceramic coating on NiCrFe alloy supports by Xiaowei Niu; He Zhang; Xiaojun Hu; Wei Han (pp. 265-269).

► The glass-ceramic coating exhibits excellent oxidation and spalling resistance. ► The addition of SiO₂ can greatly enhance the specific surface areas of the coatings. ► Crystallization of the SiO₂–Al₂O₃ coatings decreased with increasing Si contents. ► Coatings with good adherence to substrates and to improve wear resistance of the catalysts.In this paper, SiO₂–Al₂O₃ coatings were deposited on a NiCrFe alloy by dip-coating with tetraethyl orthosilicate and nitrate as the raw materials. The effects of the main preparative parameters on the coating were investigated using XRD, SEM, FTIR, thermal shock cycling, and ultrasonic vibration. The results show that the morphologies, specific surface area, adhesion and thermal stability of the coating are affected by the SiO₂ content in the SiO₂–Al₂O₃ sol and the pre-oxidation temperature of the NiCrFe support. The optimal treatment conditions for producing high-quality coatings were identified from our experimental results.

Keywords: NiCrFe alloy; IR spectroscopy; Oxide coatings; High temperature corrosion

Synthesis of well-adhered SiO₂–Al₂O₃ glass-ceramic coating on NiCrFe alloy supports by Xiaowei Niu; He Zhang; Xiaojun Hu; Wei Han (pp. 265-269).

Keywords: NiCrFe alloy; IR spectroscopy; Oxide coatings; High temperature corrosion

Roughness scaling in titanium thin films: A three-dimensional molecular dynamics study of rotational and static glancing angle deposition by Matilda Backholm; Morten Foss; Kai Nordlund (pp. 270-273).

► Glancing angle deposition (GLAD) was studied using three dimensional molecular dynamics simulations. ► The film structure and surface roughness were investigated for both static and rotational GLAD. ► The surface roughness was shown to be identical for both cases.Three-dimensional molecular dynamics simulations of the glancing angle deposition of titanium was performed both with and without substrate rotation for different deposition angles ( α=85°, 80°, 55°, and 0°). The surface roughness of the final films, all consisting of 10,000 deposited atoms, was calculated at different length scales of the substrate. The roughness scaling was shown to be, within error, identical for the rotational and static glancing angle deposited thin films.

Keywords: Glancing angle deposition; Surface roughness; Molecular dynamics simulations

Fabrication, characterization and photocatalytic activity of cubic-like ZnMn₂O₄ by Ling Zhao; Xinyong Li; Ji Zhao (pp. 274-277).

Display Omitted► The cubic-like superstructure of ZnMn₂O₄ was successfully synthesized by a facile solvothermal method. ► The cubic-like ZnMn₂O₄ has a higher surface area of 138m²g⁻¹ and monomodal pore size distributions. ► The band-gaps of the cubic-like ZnMn₂O₄ is found to be 1.3eV. ► The synthesized cubic-like ZnMn₂O₄ exhibited excellent photocatalytic activity for rhodamine B under visible-light irradiation.A type of uniform ZnMn₂O₄ with cubic-like morphology was successfully synthesized by a facile solvothermal method. The results from X-ray powder diffraction, scanning electron microscope and X-ray photoemission spectroscopy indicated that the as-prepared sample was cubic-like ZnMn₂O₄ with well crystallinity and phase purity. The average length, width and thickness of the sample are approximately 2.5μm, 1.5μm and 1.5μm, respectively. The N₂ gas adsorption–desorption isotherms results revealed that the cubic-like ZnMn₂O₄ has a higher surface area of 138m²g⁻¹ and monomodal pore size distributions. The optical property of the sample was studied by UV–vis diffuse reflectance spectroscopy. The synthesized cubic-like ZnMn₂O₄ exhibited excellent photocatalytic activity for rhodamine B under visible-light irradiation.

Keywords: ZnMn; ₂; O; ₄; Electron microscopy; XPS; Photocatalytic activity

Fabrication, characterization and photocatalytic activity of cubic-like ZnMn₂O₄ by Ling Zhao; Xinyong Li; Ji Zhao (pp. 274-277).

Keywords: ZnMn; ₂; O; ₄; Electron microscopy; XPS; Photocatalytic activity

Identification of surface composition and chemical states in composites comprised of phases with fluorite and perovskite structures by X-ray photoelectron spectroscopy by Elena Yu Konysheva; Stephen M. Francis (pp. 278-287).

► Cation rearrangement between the surface and bulk of grains was studied in composites. ► Surface of La_0.6Sr_0.4CoO₃–CeO₂ and La_0.8Sr_0.2MnO₃–CeO₂ composites is depleted in Ce. ► Ce⁴⁺ (major fraction) and Ce³⁺ cations are present at the surface or interfaces. ► Small fraction of CeO₂ facilitates surface segregation of Co cations in composites. ► O 1 s spectra vary with CeO₂ content and chemical origin of transition metal cations.X-ray photoelectron spectroscopy (XPS) has been used to explore the cation rearrangement between the surface and bulk of grains and the surface chemical states of Ce, Mn, Co, Sr, and O ions in the single phase CeO₂-based solid solutions and in the two phase (100− x)La_0.6Sr_0.4CoO₃– xCeO₂ (LSCC x) and (100− x)La_0.8Sr_0.2MnO₃– xCeO₂ (LSMC x) composites. The well-resolved Ce 3 d_5/2 and Ce 3 d_3/2 spin–orbit components were determined to study the Ce⁴⁺ to Ce³⁺ electronic transition at the surface. The surface of the LSCC x and LSMC x ( x=8–40mol%) composites is depleted in cerium. Both Ce⁴⁺ and Ce³⁺ cations were revealed. The surface fraction of Ce⁴⁺ cations increases with the rise in CeO₂ content in both systems, but it is higher by about a factor of two in the LSCC composites. A strong enrichment of the surface by Co cations was observed for the composites LSCC x ( x=8–40mol%), implying that the presence of cerium could facilitate the Co surface segregation. A slight Sr surface enrichment compared to the nominal stoichiometry was found for La_0.6Sr_0.4CoO₃, CeO₂-based solid solutions, LSCC57, and LSMC x ( x=10–57) composites. In contrast, the surface of the LSCC x ( x=10–37) composites is slightly depleted in strontium cations. The O 1 s spectra of the LSCC and LSMC composites contain several contributions associated with the lattice oxygen related to the phases with the perovskite and fluorite structures as well as with different surface states. Their contributions vary with CeO₂ content and a chemical origin of the transition metal cations on the B-site in the perovskite structure. The Ce₂(CO₃)₃-based phase seems to exist at the surface of grains and crystallites in the LSCC57 and LSCM composites.

Keywords: X-ray photoelectron spectroscopy (XPS); Surface composition; Composites with perovskite and fluorite structures; Oxidation state of cerium cations; Binding energy

Effect of gas composition on corrosion behavior and growth of apatite on plasma nitrided titanium alloy Beta-21S by L. Mohan; C. Anandan (pp. 288-296).

► Titanium alloy β21S was nitrided in 100% N₂ and H₂ diluted N₂ plasmas. ► Nitriding in H₂ diluted plasma results in higher hardness. ► Corrosion resistance of H₂ diluted sample is higher than 100% N₂ nitrided samples. ► Nitriding lowers the corrosion resistance of base alloy in SBF. ► H₂ dilution leads to more growth of hydroxide and apatite in Hank's solution.Titanium alloy beta 21S with composition Ti–15Mo–3Nb–3Al–0.2Si was plasma nitrided using inductively coupled RF Plasma with 100% N₂ and 80% N₂–20% H₂ at 800°C for 4h. XRD and micro Raman studies show the formation of titanium nitrides. Potentiodynamic polarization studies in Hank's solution show the corrosion resistance of the 80–20% (N₂–H₂) treated samples to be better than the 100% N₂ treated samples. However, untreated samples show better corrosion resistance than the treated samples. Electrochemical impedance spectroscopy (EIS) studies show higher charge transfer resistance and lower double layer capacitance for the substrate compared to the nitrided samples. FESEM images of samples immersed in SBF show that growth of apatite is more and the size of deposits are larger on nitrided samples, especially on those nitrided with hydrogen dilution, as compared to that on the untreated substrate. EDS results show a decrease in nitrogen content and increase in oxygen content after corrosion experiments. XPS spectra from the nitrided and corrosion tested samples show the presence of oxide, nitride and oxynitride on the surface and after corrosion studies the samples are covered with oxide. Nitrided samples immersed in Hank's solution for one day show higher amount of calcium, phosphorous and oxygen in hydroxide form than the substrate.

Keywords: Titanium alloy; Plasma nitriding; Corrosion; XPS; EIS; Apatite

Effect of gas composition on corrosion behavior and growth of apatite on plasma nitrided titanium alloy Beta-21S by L. Mohan; C. Anandan (pp. 288-296).

Keywords: Titanium alloy; Plasma nitriding; Corrosion; XPS; EIS; Apatite

Fabrication of Ketjen black-polybenzoxazine superhydrophobic conductive composite coatings by Lie Shen; Hongliang Ding; Wen Wang; Qipeng Guo (pp. 297-301).

Superhydrophobic conductive Ketjen black-polybenzoxazine composite coatings were prepared by a simple drop casting method with high static water contact angle (∼160°), low sliding angle (∼3°), and low sheet resistance (10³Ω/sq). The composite coatings showed hierarchically structured roughness and possessed superhydrophobicity over the whole range of pH values. Each microisland on the polybenzoxazine surface was covered with numerous Ketjen black nanospheres, leading to a higher porosity and surface roughness.Display Omitted► We report an effective approach to fabricate superhydrophobic conductive composite coatings by a drop casting method. ► No work has been reported on combining Ketjen black with polybenzoxazine to prepare superhydrophobic conductive coatings. ► The composite coatings possess superhydrophobicity over the whole range of pH values. ► These coatings exhibit excellent thermal and environmental stability. ► Superhydrophobic conductive composite coatings can be obtained on various substrates.Superhydrophobic conductive Ketjen black-polybenzoxazine (KB-PBZ) composite coatings were prepared by a simple drop casting method with high static water contact angle (∼160°), low sliding angle (∼3°), and low sheet resistance (10³Ω/sq). The relationship between Ketjen black amounts and the structure and properties of the composite coatings was investigated. Under appropriate conditions, the composite coatings showed hierarchically structured roughness and possessed superhydrophobicity over the whole range of pH values. These coatings exhibited excellent thermal and environmental stability. Moreover, the superhydrophobic conductive composite coatings also can be obtained on various substrates such as wood, aluminum foil, paper, polyethylene terephthalate film and fabric.

Keywords: Superhydrophobic; Conductive; Ketjen black; Polybenzoxazine; Coatings

Fabrication of Ketjen black-polybenzoxazine superhydrophobic conductive composite coatings by Lie Shen; Hongliang Ding; Wen Wang; Qipeng Guo (pp. 297-301).

Keywords: Superhydrophobic; Conductive; Ketjen black; Polybenzoxazine; Coatings

Effects of different polypyrrole/TiO₂ nanocomposite morphologies in polyvinyl butyral coatings for preventing the corrosion of mild steel by M.R. Mahmoudian; Y. Alias; W.J. Basirun; M. Ebadi (pp. 302-311).

Display Omitted► The PPy surface area has more effect in corrosion control than the TiO₂ NPs. ► The increase of surface area can increase the ability to interact with Cl⁻. ► The increase of surface area can continuously charge the polymer.This study addresses the synthesis and comparison of the corrosion protective properties of two different polypyrrole/TiO₂ nanocomposite (PPy/TiO₂ NC) morphologies in a polyvinyl butyral coating on mild steel. The polymerization was performed via low-temperature in situ chemical oxidative polymerization in the presence of methyl orange (MO) and dodecyl benzene sulfonic acid (DBSA). The field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) results show two different spherical and tube shapes in the core–shell structure of the PPy/TiO₂ NCs synthesized in the presence DBSA and MO, respectively. The TEM results indicate that a thinner polypyrrole (PPy) shell is synthesized on the PPy/TiO₂ NCs in the presence of MO than that synthesized in the presence of DBSA. Thermogravimetric analysis (TGA) results indicate that the mass percentages of the TiO₂ NPs in the PPy/TiO₂ NCs synthesized in the presence of MO and DBSA are 29.71 and 33.84%, respectively. The PPy/TiO₂ NCs synthesized in the presence of MO were found to yield better anti-corrosion performance than those synthesized in the presence of DBSA. This result is due to the effect of the PPy surface area, which has more influence over corrosion control than the percentage of TiO₂ nanoparticles in the nanocomposites.

Keywords: Nanocomposite; Polypyrrole; Morphology; Corrosion

High response solar-blind ultraviolet photodetector based on Zr_0.5Ti_0.5O₂ film by Min Zhang; Xuehui Gu; Kaibo Lv; Wei Dong; Shengping Ruan; Yu Chen; Haifeng Zhang (pp. 312-316).

► The Zr_0.5Ti_0.5O₂ film exhibited good morphology and excellent optical properties. ► High response solar-blind UV detector based on Zr_0.5Ti_0.5O₂ film was fabricated. ► The thermal and humidity stability of the detectors were studied.In this letter, high response solar-blind Zr_0.5Ti_0.5O₂ ultraviolet detectors with Au and Pt electrodes were fabricated. The stability and photoelectric characteristics of the devices at different temperature and relative humidity were studied. The detectors covered the whole solar-blind spectrum range and responded mainly in 200–290nm. At 5V bias, 25°C and 33% RH, the dark current of the detector with Pt electrodes was only 17pA. Under the radiation of 250nm UV light, a high responsivity of 620mA/W was obtained for Pt electrodes device. Moreover, the detector also exhibited a fast response time: the rise and fall time were 424.1 and 154ms, respectively.

Keywords: Solar-blind; Photodetector; Zr; _0.5; Ti; _0.5; O; ₂

High response solar-blind ultraviolet photodetector based on Zr_0.5Ti_0.5O₂ film by Min Zhang; Xuehui Gu; Kaibo Lv; Wei Dong; Shengping Ruan; Yu Chen; Haifeng Zhang (pp. 312-316).

Keywords: Solar-blind; Photodetector; Zr; _0.5; Ti; _0.5; O; ₂

Impact of chemical treatment on the surface, structure, optical and electrical properties of SnS thin films by N. Koteeswara Reddy; M. Devika; Yoon-Bong Hahn; K.R. Gunasekhar (pp. 317-322).

► We investigated impact of chemical treatment on the physical properties of SnS thin films. ► The SnS thin films were deposited by thermal evaporation technique. ► Chemical treated films exhibited excellent improvement in their crystalline and optical quality and thereby low electrical resistivity. ► The observed results clearly demonstrated the possibility of the development of good quality SnS films and thereby devices.The impact of chemical treatment on the surface morphology and other physical properties of tin mono-sulphide (SnS) thin films have been investigated. The SnS films treated with selected organic solvents exhibited strong improvement in their crystalline-quality and considerable decrease in electrical resistivity. Particularly, the films treated with chloroform showed very low electrical resistivity of ∼5Ωcm and a low optical band gap of 1.81eV as compared to untreated and treated SnS films with other chemicals. From these studies we realized that the chemical treatment of SnS films has strong impact on their surface morphology and also on other physical properties.

Keywords: SnS thin films; IV–VI semiconductors; Photovoltaic material; Chemical treated surfaces; Structural properties

Impact of chemical treatment on the surface, structure, optical and electrical properties of SnS thin films by N. Koteeswara Reddy; M. Devika; Yoon-Bong Hahn; K.R. Gunasekhar (pp. 317-322).

Keywords: SnS thin films; IV–VI semiconductors; Photovoltaic material; Chemical treated surfaces; Structural properties

Surface defects impeded excitons in Alq₃ based hetero junction OLEDs by P. Justin Jesuraj; K. Jeganathan (pp. 323-326).

► Alq₃ film fabricated on quartz and TPD/ITO with very low RMS of 0.74 and 0.37nm, respectively. ► Effect of pin holes on PL emission spectrum of Alq₃ and TPD/Alq₃ hetero junctions observed. ► Maximum current efficiency of 5cd/A have been achieved for Alq₃ HJOLED without any buffer layers. ► Maximum brightness of 1.02×10⁴cd/m² have been achieved for the HJOLED at optimized rate.Hetero junction organic light emitting device consists of N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine (TPD)/tris-(8-hydroxyquinoline)aluminum (Alq₃)/LiF/Al were fabricated on indium tin oxide coated corning glass substrate under various Alq₃ deposition rates. We demonstrate the significance of deposition rate on the morphology of Alq₃ layers and subsequently generation of photons in TPD/Alq₃ hetero junction. The pin holes formed on the surface of Alq₃ at low deposition rates are responsible for exciton quenching. The device fabricated with the deposition rate of 3.0Å/s exhibits the maximum luminescence and maximum current efficiency of 1.02×10⁴cd/m² and ∼5cd/A, respectively, at 15V owing to the efficient recombination of excitons in Alq₃ emissive layer.

Keywords: Organic semiconductors; Thin films; Atomic Force microscopy; Luminescence

Surface defects impeded excitons in Alq₃ based hetero junction OLEDs by P. Justin Jesuraj; K. Jeganathan (pp. 323-326).

Keywords: Organic semiconductors; Thin films; Atomic Force microscopy; Luminescence

Structure and electrical properties of Mn doped Bi(Mg_1/2Ti_1/2)O₃-PbTiO₃ ferroelectric thin films by Longdong Liu; Ruzhong Zuo; Qian Sun; Qi Liang (pp. 327-331).

► We synthesize Mn doped BMT–PT ferroelectric thin films via a sol–gel method. ► We characterize the film structure by means of XRD, AFM, SPS. ► Sol–gel derived BMT–0.37PT–0.005Mn films exhibit the optimum dielectric and ferroelectric properties.The Mn doped 0.63Bi(Mg_1/2Ti_1/2)O₃–0.37PbTiO₃ (BMT–0.37PT– xMn, x=0–0.01) thin films were deposited on Pt(111)/Ti/SiO₂/Si substrates by a sol–gel method. The effect of the Mn doping concentration on the structure and electrical properties of BMT–0.37PT thin films was studied. The X-ray diffraction data indicate that the B-site Mn substitution does not change the perovskite structure of the films. The X-ray photoelectron spectra show that Mn ions mainly exist as Mn³⁺ except for a few as Mn²⁺ for the 1mol% Mn doped BMT–0.37PT film. Moreover, it was found that the addition of a small amount of Mn effectively reduces the dielectric loss and improves the resistivity of the films. The BMT–0.37PT–0.005Mn film exhibits lower leakage current density than the undoped BMT–0.37PT film such that saturated hysteresis loops can be achieved. As a result, the BMT–0.37PT–0.005Mn film exhibits the largest permittivity ( ɛ_r∼1271 at 1kHz) and remanent polarization ( P_r∼17.4μC/cm² at 100Hz) in all studied compositions.

Keywords: Thin films; Sol–gel; Mn doping; Electrical properties

Structure and electrical properties of Mn doped Bi(Mg_1/2Ti_1/2)O₃-PbTiO₃ ferroelectric thin films by Longdong Liu; Ruzhong Zuo; Qian Sun; Qi Liang (pp. 327-331).

Keywords: Thin films; Sol–gel; Mn doping; Electrical properties

Low temperature plasma vapor treatment of thermo-sensitive poly(N-isopropylacrylamide) and its application by Y. Chen; X.L. Tang; B.T. Chen; G. Qiu (pp. 332-336).

► PNIPAAm is a thermo-sensitive polymer. ► Its lower critical solution temperature is 32°C. ► It was carried out to impart water imbitions to the glass slide. ► This application to PBT melt-blown nonwovens is quiet valuable.In this study, the novel methods of depositing poly(N-isopropylacrylamide) (PNIPAAm) coatings on the surface of glass slides and PS petri dish by plasma polymerization are provided. PNIPAAm can be obtained by plasma polymerization of N-isopropylacrylamide by using the self-made equipment of plasma vapor treatment. The samples were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and water contact angle. SEM analysis has revealed that the poly(N-isopropylacrylamide) (PNIPAAm) coatings were formed on the surface of the smooth glass slides. Further evaluation by using XPS, it has shown the presence of PNIPAAm. The wettability can be significantly modified by changing of the temperatures at above and below of the lower critical solution temperature (LCST) from the data of the contact angle test. These results have advantage for further application on the thermo-sensitive textile materials. On the deposition of PNIPAAm onto Polybutylene Terephthalate (PBT) melt-blown nonwovens in atmospheric pressure plasma, water permeability was significantly modified at around LCST. Due to the LCST is close to the temperature of human body, it has advantage on application of PBT melt-blown nonwovens.

Keywords: Surface modification; Low temperature plasma polymerization; Water contact angle; Lower critical solution temperature (LCST); Poly(N-isopropylacrylamide) (PNIPAAm)

Low temperature plasma vapor treatment of thermo-sensitive poly(N-isopropylacrylamide) and its application by Y. Chen; X.L. Tang; B.T. Chen; G. Qiu (pp. 332-336).

Keywords: Surface modification; Low temperature plasma polymerization; Water contact angle; Lower critical solution temperature (LCST); Poly(N-isopropylacrylamide) (PNIPAAm)

Effect of surface pre-treatment on the hydrophilicity and adhesive properties of multilayered laminate used for lithium battery packaging by F. Xia; S.A. Xu (pp. 337-342).

Spreading of water droplet on foil surface treated by different methods.Display Omitted► The aluminium foil used for lithium battery package was treated by different methods. ► The effects of treatment on the adhesive properties of the laminated were explored. ► Both the adhesive strength and the heat sealing strength are affected by the surface treatments. ► The porous surface can greatly enhance the adhesive strength and the heat sealing strength.The surface of aluminum foil was treated using silane coupling agent and chromate–phosphate conversion solution respectively, then a flexible laminate consisting of five layers was prepared using polypropylene film as inner sealant layer and epoxy resin as adhesive between polypropylene film and aluminum foil. The surface morphology and composition of the foil after treatment were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and the hydrophilicity of the foil was evaluated by contact angle measurement (CAM). The adhesive strength between the aluminum foil and polypropylene film, and the heat sealing strength of polypropylene film were measured by tensile tester, their dependences on the surface treatments were further investigated. It can be concluded that the adhesive strength and heat sealing strength depend on not only the hydrophilicity, but also the morphology of the foil surface. The rough and porous surface of the treated foil can enhance both the adhesive strength and heat sealing strength.

Keywords: Key words; Surface pre-treatment; Aluminum foil; Multilayered laminate; Adhesive strength

Effect of surface pre-treatment on the hydrophilicity and adhesive properties of multilayered laminate used for lithium battery packaging by F. Xia; S.A. Xu (pp. 337-342).

Keywords: Key words; Surface pre-treatment; Aluminum foil; Multilayered laminate; Adhesive strength

Morphological modifications of electrodeposited calcium phosphate coatings under amino acids effect by R. Drevet; A. Lemelle; V. Untereiner; M. Manfait; G.D. Sockalingum; H. Benhayoune (pp. 343-348).

► Calcium phosphate coatings are electrodeposited on titanium alloy substrates. ► Amino acids are added to the electrolyte to direct the calcium phosphate growth. ► Amino acids modify the coatings morphology without structural or chemical change. ► These morphological modifications improve the corrosion behaviour of the material.Calcium phosphate coatings are synthesized on titanium alloy (Ti6Al4V) substrates by pulsed electrodeposition. This work aims to observe the morphological modifications of the coating when an amino acid is added to the electrolytic solution used in the process. The effects of two amino acids (glutamic acid and aspartic acid) are studied at a low and a high concentration. The coating morphology is observed at a nanometer scale by field emission gun-scanning electron microscopy (FEG-SEM). The structural characterization of the coating is performed by Fourier transformed infrared spectroscopy (FT-IR), Raman spectroscopy and X-ray diffraction (XRD). Moreover, corrosion measurements of the prosthetic surfaces are carried out by potentiodynamic polarization experiments in a physiological solution named Dulbecco's modified eagle medium (DMEM). The results show that the addition of an amino acid to the electrolytic solution leads to the decrease of the size of the crystallites which compose the prosthetic calcium phosphate coating that becomes denser and less porous than the coatings obtained without amino acid. Consequently, the corrosion behavior of the prosthetic material immersed in DMEM is improved.

Keywords: Calcium phosphate; Electrodeposition; Electron microscopy; Corrosion; Biomaterial; Titanium alloy

Improvement on the storage performance of LiMn₂O₄ with the mixed additives of ethanolamine and heptamethyldisilazane by Xianwen Wu; Xinhai Li; Zhixing Wang; Huajun Guo; Peng Yue; Yunhe Zhang (pp. 349-354).

Display Omitted► Effect of the mixture of ethanolamine and heptamethyldisilazane on the storage behavior of LiMn₂O₄ is investigated. ► The amorphous materials on the surface of LiMn₂O₄ were characterized in details by SEM and TEM. ► The mixture of ethanolamine and heptamethyldisilazane added into LiPF₆-based electrolyte can stabilize the original morphology and spinel structure of LiMn₂O₄. ► The mixed additives can decrease Mn dissolution and reduce the content of λ-MnO₂, MnF₂ and LiF. ► The mixed additives can improve the initial discharge capacity and storage performance greatly.The commercial LiMn₂O₄ are added into the LiPF₆-based electrolyte without or with the mixed additives of ethanolamine and heptamethyldisilazane to be exposed in air at 60°C for 2–6h, and the effect of different electrolytes on the storage behavior of LiMn₂O₄ materials and LiMn₂O₄/Li cells at elevated temperature is investigated comparatively for the first time by FTIR, SEM, TEM, XRD and charge–discharge measurements. The results show that the electrochemical performances of LiMn₂O₄ exposed in the LiPF₆-based electrolyte become worse gradually with the storage time increasing. However, when the mixture of ethanolamine and heptamethyldisilazane as electrolyte additives is added into the LiPF₆-based electrolyte, it can stabilize the original morphology and spinel structure of LiMn₂O₄ greatly and improve the storage performance of the material and LiMn₂O₄/Li cells effectively. As the commercial LiMn₂O₄ is exposed in the LiPF₆-based electrolyte with additives for 4h at 60°C, the initial discharge capacity of 97.7mAhg⁻¹ at 0.1C and the capacity retention of 89.14% at 1C rate after 150 cycles are much better than that LiMn₂O₄ exposed in the LiPF₆-based electrolyte under the same conditions. Furthermore, the LiMn₂O₄/Li cells using the LiPF₆-based electrolyte with additives exhibit higher initial discharge capacity before storage and higher capacity retention after storage at 60°C for a week compared to the cells without additives in the LiPF₆-based electrolyte.

Keywords: Heptamethyldisilazane; Ethanolamine; Electrolyte; Storage performance

Adsorption of pH-responsive amphiphilic copolymer micelles and gel on membrane surface as an approach for antifouling coating by Ravikumar Muppalla; Harpalsinh H. Rana; Sadhna Devi; Suresh K. Jewrajka (pp. 355-367).

Display Omitted► pH-responsive copolymer micelles and gel were deposited on the membrane surface. ► The deposited micelles and gel remained stable on the membrane surface. ► The modified membranes show improved antifouling properties and performance. ► The modified membranes show pH dependent performance during filtrations operation. ► Stability of micelles and gel was assessed by IR, SEM, CA, and zeta potential.A new approach for the surface modification of polymer membranes prepared by phase inversion technique for antifouling properties is reported. Direct deposition of poly(2-dimethylaminoethyl methacrylate)-b–poly(methyl methacrylate)-b–poly(2-dimethylaminoethyl methacrylate) (PDMA-b–PMMA-b–PDMA) copolymer micelles (core–shell) and gel formed from mixture of polyvinyl alcohol (PVA) and PDMA-b–PMMA-b–PDMA on the polysulfone (PSf-virgin) ultrafiltration membrane surface successfully provides modified membranes with improved antifouling properties and pH-responsive behaviour during both water and protein filtrations. Successful deposition and adsorption of such type of micelle and gel particles on the membrane surface was assessed by combination of SEM, AFM, contact angle, ATR-IR, and zeta potential measurements. The micelle and gel particles preferentially remained on the membranes surface due to their bigger size than the pores on the skin layer and also due to adsorption on the membrane surface by hydrophobic interaction. The modified membranes exhibited much higher rejection of macromolecules and almost steady trend in flux compared to corresponding virgin membranes during filtration operation. The major advantage of this protocol is that the deposited micelles and gel remained on the membrane surface even after filtration and storage of the membrane in water and the modified membranes retained similar performance. The effect of all the micelles and gel components on the membrane performance has been elucidated.

Keywords: Key words; Micelles adsorption; Micelles and gel deposited membrane; Antifouling properties; Protein filtration; pH responsive membrane

Low-temperature solid state bonding method based on surface Cu–Ni alloying microcones by Qin Lu; Zhuo Chen; Wenjing Zhang; Anmin Hu; Ming Li (pp. 368-372).

► A low-temperature insertion bonding method based on Cu–Ni cones was studied. ► Cu–Ni cones inserted into solder and a thin intermetallic compound layer formed. ► Bonding joint strength obtained here is comparable to that of reflow soldering.A low-temperature solid state bonding method based on surface Cu–Ni alloying microcones for potential application in 3D integration is introduced. Surface Cu–Ni alloying microcones were fabricated by electroless deposition and bonded with Sn–3.0Ag–0.5Cu (wt.%) solder at 190°C (solid state) in ambient air. Microscopic observation showed that Cu–Ni microcones inserted into the soft solder effectively and a thin intermetallic compound layer formed along the bonding interface. The bonding joint strength was measured and the result showed that it was higher than that of reflow soldering.

Keywords: 3D integration; Low-temperature bonding; Cu–Ni microcones; Bonding strength; Interfaces; Diffusion

Low-temperature solid state bonding method based on surface Cu–Ni alloying microcones by Qin Lu; Zhuo Chen; Wenjing Zhang; Anmin Hu; Ming Li (pp. 368-372).

Keywords: 3D integration; Low-temperature bonding; Cu–Ni microcones; Bonding strength; Interfaces; Diffusion

Synthesis and characterization of self-crosslinking fluorinated polyacrylate soap-free latices with core–shell structure by Wei Xu; Qiufeng An; Lifen Hao; Dan Zhang; Min Zhang (pp. 373-380).

Self-crosslinking fluorinated polyacrylate soap-free latices (FMBN) were prepared in our work. There were many little protuberances or peaks on the FMBD film dried at room temperature and after the annealing process, which were believed to be resulting from the phase-separated fluoroalkyl groups. The surface roughness of the FMBN film after the annealing process seemed more than that before annealing process, RMS roughnesses of those two films attained 26.84 and 9.754nm, respectively. In addition, water contact angles on those two polymer films were 115.5° and 117.5°, respectively.Display Omitted► We synthesized series of self-crosslinking fluorinated polyacrylate soap-free latices. ► Many little protuberances appeared on the fluorine-containing FMBN film surface. ► Some peaks and little protuberances appeared on that film after annealing process. ► Surface roughness of the FMBN film after the annealing treatment became larger. ► Water contact angles on those two polymer films were 115.5° and 117.5°, respectively.Novel self-crosslinking fluorinated polyacrylate soap-free latices (FMBN) with core–shell structure were synthesized by semicontinuous seeded emulsion polymerization method from dodecafluoroheptyl methacrylate (DFMA), methyl methacrylate (MMA), butyl acrylate (BA), and N-methylolamide (NMA) in the presence of a polymerizable emulsifier-ammonium allyloxtmethylate nonylphenol ethoxylates sulfate (DNS-86). Effects of the DNS-86 and DFMA amounts on stability and properties of the FMBN emulsions were studied. Besides, the latices and their film were characterized by Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (¹H NMR) spectrum, scanning electron microscopy (SEM), transmission electron microscopy (TEM), laser particle size analyzer, differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), contact angle goniometer, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), respectively. FT-IR spectra and¹H NMR spectrum showed that DFMA successfully participated in soap-free emulsion polymerization and monomers formed the fluorinated acrylate copolymer. The resulted latex particles had the core–shell structure. The films formed from the FMBN latices thus had two T_g. Their thermal stability and T_g of the shell phase increased gradually with augment of DFMA amount in polymer. XPS, AFM and hydrophobicity analyses indicated the fluoroalkyl groups had the tendency to enrich at the film–air interface. This enrichment of fluorine at the film–air interface was more evident after the annealing process. Water contact angles of the FMBN film before and after the annealing process could attain 115.5° and 117.5°, individually.

Keywords: Soap-free emulsion; Fluorinated polyacrylate; Core–shell polymers; Self-crosslinking

Synthesis and characterization of self-crosslinking fluorinated polyacrylate soap-free latices with core–shell structure by Wei Xu; Qiufeng An; Lifen Hao; Dan Zhang; Min Zhang (pp. 373-380).

Keywords: Soap-free emulsion; Fluorinated polyacrylate; Core–shell polymers; Self-crosslinking

Effect of Ti-OH groups on microstructure and bioactivity of TiO₂ coating prepared by micro-arc oxidation by Peng Zhang; Zhiguo Zhang; Wei Li; Min Zhu (pp. 381-386).

► TiO₂ bioactivity coating was fabricated by a two-step micro-arc oxidation (MAO). ► The Ti-OH groups took a key role in the apatite formation inducing and promoting in this study. ► The previous introduction of Ca and P could increase the opportunity to form hydroxyapatite. ► The combination of MAO treatment and heated alkaline MAO treatment showed beneficial effects on the biocompatibility of Ti implant. ► TiO₂ coating with Ti-OH groups showed superior bioactivity.Titanium and its alloys are promising biomedical metal materials. In order to improve the bioactivity of TiO₂ coatings, three processes including micro-arc oxidation (MAO) in a Ca and P ion electrolyte (Ti-MAO), MAO in a 1M NaOH electrolyte (Ti-NaOH) which was heated to 60°C and a two-step MAO process in which specimens were first treated by MAO in Ca and P ion solution and then further in a 1M heated NaOH electrolyte in succession (Ti-MAO-NaOH) were carried out. Round pores were found to form on the surface of the Ti-MAO sample while homogeneously distributed hollow spherical particles were found on both the Ti-NaOH and Ti-MAO-NaOH sample surfaces. The bioactivity evaluation showed that the combination of MAO processes in different electrolytes induced more rapid formation of apatite in contrast to the simple MAO treatment in heated alkaline electrolyte. The Ti-OH groups formed in alkaline electrolyte are found to be response for the rapid formation of hydroxyapatite during a SBF soaking. The previous introduction of Ca and P can increase the opportunity to form hydroxyapatite.

Keywords: Micro-arc oxidation; TiO; ₂; coating; Bioactivity; Simulated body fluid

Effect of Ti-OH groups on microstructure and bioactivity of TiO₂ coating prepared by micro-arc oxidation by Peng Zhang; Zhiguo Zhang; Wei Li; Min Zhu (pp. 381-386).

Keywords: Micro-arc oxidation; TiO; ₂; coating; Bioactivity; Simulated body fluid

The evolution of Cu₃N films irradiated by femtosecond laser pulses by S.Y. Wang; J.H. Qiu; X.Q. Wang; N.Y. Yuan; J.N. Ding; W.H. Huang (pp. 387-390).

► The metastable copper nitride films were studied by femtosecond laser pulses irradiation. ► The femtosecond laser process generates the metal precipitation of Cu in the copper nitride matrix at the nanometer scale. ► The microstructure, morphology and electrical resistance of Cu₃N films present regular changes with the decrease of laser power density. ► A delicate balance of ablated and decomposed contributions to determine the optimal decomposed rate of Cu₃N films induced by femtosecond laser. ► The resistance value of some samples is low enough to serve as a conductive layer for microelectronic application after irradiation.Copper nitride (Cu₃N) films have been prepared on glass substrates by DC magnetron sputtering in the presence of an Ar+N₂ atmosphere at room temperature. We study the surface chemicals and structures of Cu₃N films irradiated by tightly focused femtosecond laser pulses in the air. The evolution of microstructure, morphology of Cu₃N films is analyzed by means of X-ray diffraction (XRD), optical microscopy (OM), and scanning electron microscopy (SEM). XRD analyses clearly indicate that Cu phases are formed under femtosecond laser irradiation. Moreover, SEM images show that dispersed particles on the surface tend to form continuous porous films with decrease of laser power density.

Keywords: Copper nitride; Femtosecond laser; Copper

The evolution of Cu₃N films irradiated by femtosecond laser pulses by S.Y. Wang; J.H. Qiu; X.Q. Wang; N.Y. Yuan; J.N. Ding; W.H. Huang (pp. 387-390).

Keywords: Copper nitride; Femtosecond laser; Copper

Effects of duty cycle on properties of CIGS thin films fabricated by pulse-reverse electrodeposition technique by Harsharaj S. Jadhav; Ramchandra S. Kalubarme; SeJin Ahn; Jae Ho Yun; Chan-Jin Park (pp. 391-396).

► Comparison between two modes of deposition. ► Effect of different modes on structure, morphology and chemical composition of CIGS thin films. ► Effect of duty cycle on the structure, morphology and chemical composition of the CIGS layer. ► The growth mechanism of CIGS thin films in DC and pulse-reverse electrodeposition mode.DC and pulse-reverse electrodeposition mode were employed for the deposition of polycrystalline Cu(In,Ga)Se₂ thin films. In comparison with DC electrodeposition mode, films obtained by pulse-reverse electrodeposition were smoother, denser and more uniform with good adhesion. The Ga content in final composition of CIGS thin film was improved in pulse-reverse electrodeposition mode. In addition, pulse-reverse electrodeposited CIGS thin films were more crystalline with chalcopyrite structure. The compact morphology without pores in the deposit was achieved in the pulse-reverse electrodeposited CIGS thin films by varying duty cycle.

Keywords: Cu(In,Ga)Se; ₂; Thin films; Solar cell; Pulse-reverse electrodeposition; Duty cycle

Time dependent statistics of plasma discharge parameters during bulk AC plasma electrolytic oxidation of aluminium by C.S. Dunleavy; J.A. Curran; T.W. Clyne (pp. 397-409).

► A method for measurement of plasma electrolytic discharge parameters is presented. ► Plasma discharge parameters such as current and duration are measured. ► Plasma parameters are presented as a function of processing duration. ► Quantitative relations between plasma discharge parameters are presented. ► Peak current of plasma discharges is demonstrated to be bounded by applied voltage.A method for the measurement of parameters of plasma discharge events during plasma electrolytic oxidation processing is detailed and applied to AC plasma electrolytic oxidation of aluminium. Data were obtained for processing durations from 2.5 to 40min. Statistical distributions of plasma discharge parameters such as duration, peak current and charge transferred, are measured and presented as functions of processing duration. Event durations spanned 10–400μs. Discharge currents were from <10mA to more than 100mA. Charge transfer by single events ranged from <1μC to over 20μC. The frequency of plasma discharges per unit time and area was determined throughout processing, falling from initial values in the range 300–350mm⁻²s⁻¹ to fewer than 50mm⁻²s⁻¹ after 1000s of processing. A correlation between the upper bound of plasma electrical energy dissipation and the typical size of coating surface features (represented by coating roughness) is demonstrated. Quantitative relationships between discharge duration, peak current and the applied voltage are presented and compared to previously published data for a simpler, but less representative of coating deposition, experimental DC plasma electrolytic oxidation system. It is demonstrated that plasma electrolytic oxidation plasma discharge current is bounded by the applied voltage during processing.

Keywords: Discharge; Electrolytic; Micro-arc; Plasma; Oxide-coatings; MAO; PEO

Time dependent statistics of plasma discharge parameters during bulk AC plasma electrolytic oxidation of aluminium by C.S. Dunleavy; J.A. Curran; T.W. Clyne (pp. 397-409).

Keywords: Discharge; Electrolytic; Micro-arc; Plasma; Oxide-coatings; MAO; PEO

Surface modification of nanosheet oxide photocatalysts by Victoria L. Blair; Eric J. Nichols; Jian Liu; Scott T. Misture (pp. 410-415).

Display Omitted► Several new Aurivillius phases identified as active photocatalysts. ► Protonation followed by dehydration increases the photoreaction rate by 3 times. ► High energy milling decreased particle size without degrading photoactivity. ► Photodegradation occurs only on the particle surfaces, not in interlayer galleries.A range of Aurivillius oxides of the form Bi₂A n₋₁B_nO3 n₊₃ were evaluated for photodegradation of methylene blue dye. Variants included 2-, 3-, and 4-layered materials with B=Ti, Nb, or Ta and A=alkaline earths, alkali and rare earths. All phases were tested as their parent oxides and after acid-exchange to form stacked protonated nanosheets. Several high-activity catalysts were identified and improvements in the photodegradation rates were achieved both by milling to increase surface area and separately by acid protonation followed by dehydration. Both processes yielded marked improvements in the photodegradation rates, some with more than 3 times improvement. The improvement is attributed to improved adsorption after the surface reconstruction that occurs with acid treatment and dehydration.

Keywords: Photocatalyst; Aurivillius; Layered perovskite; Topochemical exchange

Surface modification of nanosheet oxide photocatalysts by Victoria L. Blair; Eric J. Nichols; Jian Liu; Scott T. Misture (pp. 410-415).

Keywords: Photocatalyst; Aurivillius; Layered perovskite; Topochemical exchange

Defect analysis and mechanical performance of plasma-deposited thin films on flexible polycarbonate substrates by Rakhi P. Patel; Colin A. Wolden (pp. 416-424).

Display Omitted► Introduce a simple technique for visualization of nanoscale defects. ► Applied to transparent films on flexible substrates. ► Demonstrate the utility of nanolaminates for defect reduction. ► Identify critical strain thresholds for amorphous ITO.A simple solvent-etch based technique is developed to visualize and quantify defects in transparent thin films deposited on flexible polymer substrates. This approach is used to characterize defects in as-deposited films and to monitor their evolution as a function of applied and repetitive bending. Thin films investigated include sputtered indium tin oxide (ITO) and alumina–silicone nanolaminates fabricated by plasma-enhanced chemical vapor deposition. It is shown that the use of nanolaminate architectures reduces the defect density by two orders of magnitude relative to a single alumina layer. The pinhole density increases when nanolaminates are subjected to applied stress, and at a critical density of ∼10/mm² the isolated defects coalesce into macroscopic cracks. In the case of ITO an optimum film thickness is identified that balances electronic performance with mechanical integrity. Conductivity correlates with defect density, and the films displayed very similar performance under tensile and compressive strain. A critical radius of curvature of 0.75in. was identified, but films cycled below the threshold strain demonstrated robust performance, with only negligible changes in resistivity through 2000 bending cycles. The strong performance under strain is attributed to the amorphous nature of the sputtered ITO.

Keywords: Defects; Flexible; ITO; Nanolaminates

Defect analysis and mechanical performance of plasma-deposited thin films on flexible polycarbonate substrates by Rakhi P. Patel; Colin A. Wolden (pp. 416-424).

Keywords: Defects; Flexible; ITO; Nanolaminates

Preparation of Pt nanoparticles on different carbonaceous structure and their applications to methanol electro-oxidation by Jih-Mirn Jehng; Wen-Jay Liu; Tsung-Chi Pan; Yong-Ming Dai (pp. 425-431).

► Upon exfoliation, oxygen containing groups are mostly on the outer surface of GO. ► The surface oxygen-containing groups also affect the metal particle size on GO. ► The Pt/GO catalyst has a higher tolerance to CO for methanol electro-oxidation. ► The Pt/GO catalyst as electrode has a good potential for application in DMFC.The efficiency of the direct methanol fuel cell (DMFC) is related to the dispersion of the metal catalyst on the support as electrode. It is important for the support to possess a high surface area, uniform pore size, and good conductivity properties. Graphene oxide (GO) is a newly developed 2-dimension material containing those excellent properties. The physical properties and structural information of the Pt/GO catalysts were further characterized by XRD, TEM, and XPS techniques. The TEM and XRD have revealed that the Pt/GO electrode catalyst prepared by polyol process possess a uniform dispersion and particle size within the range of 2–3nm. The electrocatalytic properties of Pt/GO composites and kinetic characterization for methanol electro-oxidation were investigated by cyclic voltammetry. In addition, the Pt/GO shows better tolerance to CO for methanol electro-oxidation compared to the Pt/CNT catalyst. The results suggest that the Pt/GO catalyst as electrode has a good potential for application in DMFC.

Keywords: Direct methanol fuel cell (DMFC); Graphene oxide (GO); Methanol electro-oxidation

Preparation of Pt nanoparticles on different carbonaceous structure and their applications to methanol electro-oxidation by Jih-Mirn Jehng; Wen-Jay Liu; Tsung-Chi Pan; Yong-Ming Dai (pp. 425-431).

Keywords: Direct methanol fuel cell (DMFC); Graphene oxide (GO); Methanol electro-oxidation

Supramolecular interactions of anthraquinone networks on Au(111): Hydrogen bonds and van der Waals interactions by Ji Yeon Kim; Won Jun Jang; Howon Kim; Jong Keon Yoon; Jihun Park; Se-Jong Kahng; Jhinhwan Lee; Seungwu Han (pp. 432-435).

Display Omitted► We studied intermolecular interactions of supramolecular structures of anthraquinone molecules on Au(111) using scanning tunneling microscopy. ► We observed the molecular chains of linear and zigzag structures, and the molecular islands of square and chevron structures. ► Molecular models for the observed structures were explained with hydrogen bonds and van der Waals interactions, as revealed with our density functional theory calculations. ► Our study shows that van der Waals interactions play cooperative roles in determining the hydrogen bonded networks of the system.Intermolecular interactions of supramolecular structures were studied in anthraquinone molecules on Au(111) using scanning tunneling microscopy. Molecular chains of linear and zigzag structures were observed and explained with simple models of hydrogen bonds. In two-dimensional islands, square and chevron structures were observed, and their molecular models were reproduced by density functional theory calculations. Square structures were made of four hydrogen bonds per molecule, whereas chevron structures were explained with four hydrogen bonds per molecule and additional van der Waals interactions. Our study shows that van der Waals interactions play cooperative roles in determining the hydrogen bonded networks of the system.

Keywords: Scanning tunneling microscope; Hydrogen bond; Supramolecular network; Van der Waals interaction

A DFT study on the functionalization of a BN nanosheet with PCX, (PC=phenyl carbamate, X=OCH₃, CH₃, NH₂, NO₂ and CN) by Javad Beheshtian; Hamed Soleymanabadi; Ali Ahmadi Peyghan; Zargham Bagheri (pp. 436-441).

► Reaction of some organo-azo molecules with BN sheet is investigated using DFT. ► Reaction energies ( E_r) have been calculated to be in the range of 0.19 to 0.35. ► E_r enhances, increasing the electron withdrawing characteristic of the functionals. ► The reaction may impede the field electron emission from the sheet surface.By using density functional theory calculations, we investigated the chemical functionalization of a BN nanosheet with different organo-azo derivatives including PCX, (PC=phenyl carbamate, X=OCH₃, CH₃, NH₂, NO₂ and CN) in terms of geometric, energetic, and electronic properties. Reaction energies have been calculated to be in the range of 0.19 to 0.35eV which is augmented by increasing the electron withdrawing characteristic of the functional groups so that the relative magnitude order isNO₂>CN>OCH₃>CH₃>NH₂. The chemical functionalization leads to a decrease in HOMO/LUMO energy gap of BN sheet especially after adsorption of PCNO₂ by about 1.88eV. Conduction level and Fermi level of the BN sheet are shifted to lower energies upon the functionalization of the sheet with PCNO₂ and PCCN, thus, it leads to an increment in work function of the sheet, impeding the field electron emission.

Keywords: DFT; Boron Nitride Nanosheet; B3LYP; Adsorption; Functionalization

The impact of rubbing fabric type on surface roughness and tribological properties of some semi-alicyclic polyimides evaluated from atomic force measurements by Iuliana Stoica; Andreea Irina Barzic; Camelia Hulubei (pp. 442-449).

Display Omitted► Effect of rubbing fiber size and flexibility on polyimide surface regularity and uniformity. ► Effect of polyimide structural organization on surface features created after rubbing. ► Tribological parameters in evidencing polyimide surface ordering.The morphology of some polyimides (PI) prepared from a flexible and alicyclic dianhydride, in combination with aromatic diamines was investigated in detail before and after rubbing with two types of fabric: cotton velvet (CV) and cellulose diacetate velvet (CDV). Atomic force microscopy was employed to evaluate the correlation between rubbing-induced grooves in PI film and size/flexibility of textile fibers. For both samples surface isotropy decreased appreciatively with 91% after patterning since the appearance of ordered nanostructures in the direction of rubbing. The angular spectra reveal the generation of a surface anisotropy after rubbing process and a higher surface regularity and uniformity when using CV. This result is confirmed by decrease of texture direction index with 75% and of surface texture aspect ratio with 89%. These parameters together with the rubbing fiber characteristics are key factors in controlling liquid crystal alignment on patterned PI surfaces.

Keywords: Polyimide; Rubbing fabric; Atomic force microscopy; Morphology; 3D-surface roughness parameters

Tuning the resistance of polycarbonate membranes by plasma-induced graft surface modification by Lukas Baumann; Dirk Hegemann; Damien de Courten; Martin Wolf; René M. Rossi; Wolfgang P. Meier; Lukas J. Scherer (pp. 450-457).

Display Omitted► The hydrophilicity of porous PC membranes can be adjusted. ► Long-term stable surfaces are obtained. ► The resistance of porous PC membranes for caffeine can be tuned. ► Surface–water interaction has a major impact on the membrane permeability. ► Functional coatings can be post-modified to adapt its permeability resistances.To tune the permeability resistance of porous polycarbonate (PC) membranes for caffeine, their surfaces were plasma modified with different monomers in a grafting from process. These coatings provided characteristic surface hydrophilicities. It was found that membranes with more hydrophilic surfaces have lower resistances to let caffeine pass through than membranes with hydrophobic surfaces. Additionally, it was possible to post-modify a poly(2-aminoethyl methacrylate) (AEMA) coated PC membrane with octanoic acid (Oct) under mild conditions. This post modification allowed transforming a slightly hydrophilic PC-AEMA membrane with a moderate permeability resistance into a hydrophobic PC-AEMA-Oct membrane with a high permeability resistance. Overall, it was possible to tune the PC membrane resistance for caffeine in a range from 5100 up to 15,100s/cm.

Keywords: Surface coating; Membrane permeability; Caffeine delivery; Controlled delivery; Surface hydrophilicity; Plasma induced surface modification

Synthesis and magnetic property of Fe doped LaPO₄ nanorods by Donglin Guo; Chenguo Hu; Yi Xi (pp. 458-463).

The pure LaPO₄ shows paramagnetism at room temperature, while Fe doped LaPO₄ shows ferromagnetism. The origin of the ferromagnetism of Fe doped LaPO₄ is mediated by double exchange mechanism.Display Omitted► Fe doped LaPO₄ nanorods are synthesized by hydrothermal method. ► The optical and magnetic property of Fe doped LaPO₄ are investigated. ► The mechanism of magnetic property of Fe doped LaPO₄ is explained by Density Functional Theory.Monoclinic LaPO₄ and Fe doped LaPO₄ have been prepared by the hydrothermal method in an acid aqueous solution. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectrum and X-ray photoelectron spectra are used to characterize the structure, morphology and composition of the samples. The pure LaPO₄ sample shows paramagnetism at room temperature, but the Fe doped LaPO₄ sample shows ferromagnetism with the coercivity of 166Oe and saturated magnetization of 3.28×10⁻²emu/g, respectively. The magnetic mechanism of the Fe doped LaPO₄ sample has been discussed according to the electron density of states calculation by using the Vienna ab initio simulation package. The results indicate that the origin of ferromagnetism is mediated by the double exchange mechanism, in which impurity bands are formed and partially occupied in the band gap of the LaPO₄, and the exchange split is larger than the bandwidth of t_2g.

Keywords: Nanorod; Orthophosphate; Chemical synthesis; Magnetic property

Synthesis and magnetic property of Fe doped LaPO₄ nanorods by Donglin Guo; Chenguo Hu; Yi Xi (pp. 458-463).

Keywords: Nanorod; Orthophosphate; Chemical synthesis; Magnetic property

Superhydrophobic nanostructured Kapton^® surfaces fabricated through Ar+O₂ plasma treatment: Effects of different environments on wetting behaviour by Harish C. Barshilia; A. Ananth; Nitant Gupta; C. Anandan (pp. 464-471).

► Superhydrophobicity attained on Kapton^® surfaces after Ar+O₂ plasma treatment. ► Transition from nano-feathers to nano-tussock morphology was observed as treatment time was increased. ► Contact angle of 157^ο was achieved by 1h Ar+O₂ plasma treatment and subsequent 48h low vacuum ageing. ► AFM, FESEM, FTIR, XPS and micro-Raman characterizations of Kapton^® were performed to probe the surface modifications. ► Changes in wetting characteristics were also studied as a result of ageing in various atmospheric environments.Kapton^® [poly (4,4′-oxy diphenylene pyromellitimide)] polyimides have widespread usage in semiconductor devices, solar arrays, protective coatings and space applications, due to their excellent chemical and physical properties. In addition to their inherent properties, imparting superhydrophobicity on these surfaces will be an added advantage. Present work describes the usage of Ar+O₂ plasma treatment for the preparation of superhydrophobic Kapton^® surfaces. Immediately after the plasma treatment, the surfaces showed superhydrophilicity as a result of high energy dangling bonds and polar group concentration. But the samples kept in low vacuum for 48h exhibited superhydrophobicity with high water contact angles (>150°). It is found that the post plasma treatment process, called ageing, especially in low vacuum plays an important role in delivering superhydrophobic property to Kapton^®. Field emission scanning electron microscopy and atomic force microscopy were used to probe the physical changes in the surface of the Kapton^®. The surfaces showed formation of nano-feathers and nano-tussock microstructures with variation in surface roughness against plasma treatment time. A thorough chemical investigation was performed using Fourier transform infrared spectroscopy and micro-Raman spectroscopy, which revealed changes in the surface of the Ar+O₂ plasma treated Kapton^®. Surface chemical species of Kapton^® were confirmed again by X-ray photoelectron spectroscopy spectra for untreated surfaces whereas Ar+O₂ plasma treated samples showed the de-bonding and re-organization of structural elements. Creation of surface roughness plays a dominant role in the contribution of superhydrophobicity to Kapton^® apart from the surface modifications due to Ar+O₂ plasma treatment and ageing in low vacuum.

Keywords: Ar; +; O; ₂; plasma etching; Surface morphology; Surface roughness; Contact angle; Superhydrophobicity

Temperature and size effects on electrical properties and thermoelectric power of Bismuth Telluride thin films deposited by co-sputtering by Zhigang Zeng; Penghui Yang; Zhiyu Hu (pp. 472-476).

► Grain size of annealed Bi₂Te₃ film increases with increasing of thickness. ► Electrical conductivity of annealed films increases with increasing of grain size. ► Seebeck coefficient of films increases with increasing of thickness. ► Various physical parameters have been calculated by classical size effect theory. ► The electron–phonon interaction is the main scattering mechanism in Bi₂Te₃ films.N-type Bismuth telluride thin films of different thicknesses were deposited on cleaned glass substrate at room temperature by co-sputtering technique. The films were annealed at 300°C for 12h in nitrogen atmosphere to improve their properties. The thermoelectric power and electrical properties measurements were carried out on the films with thickness from 70nm to 480nm in the temperature range 300–430K. The thickness dependence of electrical resistivity and Seebeck coefficient of annealed films was analyzed using the effective mean free path model. Some physical parameters such as effective mean free path of charge carriers in hypothetical bulk, the exponent of the energy term of mean free path, activation energy, and the Fermi energy were calculated. Both the electrical conductivity and the Seebeck coefficient of the bismuth telluride films increased with increasing of film thickness and grain size. Films with fewer grain boundaries and defects have longer effective mean free path of carriers and the mean free path decreases with the increase of temperature. The electron–phonon interaction was considered as the main scattering mechanism in the annealed bismuth telluride thin films.

Keywords: Bismuth telluride; Thermoelectric; Size effect; Electrical property

Temperature and size effects on electrical properties and thermoelectric power of Bismuth Telluride thin films deposited by co-sputtering by Zhigang Zeng; Penghui Yang; Zhiyu Hu (pp. 472-476).

Keywords: Bismuth telluride; Thermoelectric; Size effect; Electrical property

Improved functionalization of electrospun PLLA/gelatin scaffold by alternate soaking method for bone tissue engineering by Amit K. Jaiswal; Sachin S. Kadam; Vivek P. Soni; Jayesh R. Bellare (pp. 477-488).

► Hydroxyapatite (HA) worked as a binder of gelatin in composite scaffold. ► Osteoblasts activity was found to be highest on PLLA/Gel/HA at day 7 compared to all other scaffolds. ► PLLA/Gel and PLLA/Gel/HA exhibited minimum terminal complement complex concentration. ► PLLA/Gel/HA scaffold displayed better osteostimulation with lesser immune response.Biomimetic biomaterials are widely being explored as scaffold for bone regeneration. In this study, we prepared poly-l-lactic acid/hydroxyapatite (PLLA/HA) and poly-l-lactic acid/gelatin/hydroxyapatite (PLLA/Gel/HA) scaffold by electrospinning of poly-l-lactic acid (PLLA) and a blend of poly-l-lactic acid/gelatin (PLLA/Gel) followed by hydroxyapatite (HA) mineralization via alternate soaking in calcium and phosphate (Ca–P) solutions. HA growth on scaffold after each soaking cycle was confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The functional groups (COO andNH₂) of gelatin in the PLLA/Gel scaffold facilitated the surface nucleation of HA as compared to the PLLA scaffold. Leaching study showed HA in PLLA/Gel/HA scaffold acts as binder of gelatin and eliminates use of toxic crosslinking agents. In vitro cell attachment on these scaffolds was assessed by using human osteosarcoma cells (MG-63). Cell proliferation on scaffolds was examined by MTT assay. MTT results clearly indicated that mineralized scaffolds did not inhibit the eventual cell proliferation. Alkaline phosphatase (ALP) activity of MG-63 cells was found to be the highest on PLLA/Gel/HA at day 7 compared to all other scaffolds. Complement activation study revealed minimum terminal complement complex (TCC) concentration for PLLA/Gel and PLLA/Gel/HA (617.33 and 654.13ng/mL respectively). These results demonstrate the proficiency of PLLA/Gel/HA scaffold in better osteostimulation with lesser immune response, which attributed to synergistic role of gelatin and HA. Thus, by mimicking the natural microenvironment PLLA/Gel/HA scaffolds can become the choice of material in bone tissue engineering.

Keywords: Biomaterials; Biomimetic; Electrospinning; Mineralization; Cell proliferation; Complement activation

The facile preparation for temperature sensitive silica/PNIPAAm composite microspheres by Xiumei Tai; Jing hong Ma; Zhiping Du; Wanxu Wang (pp. 489-495).

Display Omitted► The optimum reaction conditions of temperature sensitive SiO₂/PNIPAAm composites are supported. ► The products prepared have obvious temperature sensitive property. ► The products show excellent monomodel microsphere.The temperature sensitive SiO₂/PNIPAAm composite microspheres were designed and successfully synthesized. The influences of monomer concentration, reaction time, reaction temperature and initiator amount on water contact angel of the prepared microspheres were investigated. The structure, morphology, and surface composition were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS). The temperature sensitive properties in aqueous solution were studied by water contact angle measurement instrument and dynamic light scatter (DLS). The results show that the low critical solution temperature (LCST) of SiO₂/PNIPAAm composites is around 304K and the particle is monodisperse microsphere.

Keywords: Temperature sensitive material; Silica/PNIPAAm; Monodisperse; Composite microsphere

The facile preparation for temperature sensitive silica/PNIPAAm composite microspheres by Xiumei Tai; Jing hong Ma; Zhiping Du; Wanxu Wang (pp. 489-495).

Keywords: Temperature sensitive material; Silica/PNIPAAm; Monodisperse; Composite microsphere

Characterization of surface oxides on water-atomized steel powder by XPS/AES depth profiling and nano-scale lateral surface analysis by D. Chasoglou; E. Hryha; M. Norell; L. Nyborg (pp. 496-506).

► More than 90% of the powder surface is covered by thin (∼6nm) Fe-oxide layer. ► Fine oxides rich in Cr, Mn and Si are also present on the powder surface. ► Cr-oxide is present only in the fine oxides and not in the surface oxide layer. ► 2 categories of the fine oxides are recognized according to composition and size. ► In the agglomerates the oxide phases appear as “glued” adjacent particulates.Characterization of oxide products on the surface of water-atomized steel powder is essential in order to determine the reducing conditions required for their removal during the sintering stage which in turn will result in improved mechanical properties. Pre-alloyed powder with 3wt% Cr and 0.5wt% Mo was chosen as the model material. Investigation of the powder surface characteristics with regard to composition, morphology, size and distribution of surface oxides was performed using X-ray photoelectron spectroscopy, Auger electron spectroscopy and high resolution scanning electron microscopy combined with X-ray microanalysis. The analysis revealed that the powder is covered by a homogeneous (∼6nm thick) Fe-oxide layer to ∼94% whereas the rest is covered by fine particulate features with the size below 500nm. These particulates were further analyzed and were divided into three main categories (i) Cr-based oxides with simultaneous presence of nitrogen, (ii) Si-based oxides of “hemispherical” shape and (iii) agglomerates of the afore mentioned oxides.

Keywords: Alloyed sintered steels; Water atomized powder; Surface oxides; XPS/AES analysis; Depth profiling; Surface coverage; HR SEM; +; EDX analysis

Characterization of surface oxides on water-atomized steel powder by XPS/AES depth profiling and nano-scale lateral surface analysis by D. Chasoglou; E. Hryha; M. Norell; L. Nyborg (pp. 496-506).

Keywords: Alloyed sintered steels; Water atomized powder; Surface oxides; XPS/AES analysis; Depth profiling; Surface coverage; HR SEM; +; EDX analysis

Growth of silver on ZnO and SnO₂ thin films intended for low emissivity applications by Rafael Alvarez; Juan C. González; Juan P. Espinós; Agustin R. González-Elipe; Ana Cueva; Francisco Villuendas (pp. 507-515).

► SnO₂ and ZnO thin films were grown by reactive magnetron sputtering. ► The films reveal slight differences in the microstructure and optical properties. ► Different growth mechanisms for the films were proven by dynamic scaling analysis. ► XPS peak shape analysis showed that silver spreads better on ZnO than on SnO₂. ► Better silver wetting of ZnO enhances the performance of low emissivity coatings.In the present work we have investigated the relationships existing between the optical properties and the growth mechanism, microstructure and surface roughness of SnO₂ and ZnO oxide films prepared by magnetron sputtering under conditions resembling those utilized in industry. Thin films of these oxides with different thicknesses were characterized by atomic force microscopy, glancing incidence X-ray diffraction (GIXRD), X-ray reflectometry and spectroscopic ellipsometry. The roughness evolution of the film properties (density, surface roughness and refraction index) as a function of their thickness has been evaluated within the concepts of the Dynamic Scaling Theory of thin film growth. Zinc oxide films were rougher than tin oxide films of similar thickness, indicating a different growing mechanism for the two materials. Silver was evaporated onto the surface of the two oxide thin films and its earlier stages of nucleation studied by background analysis of the X-ray photoemission spectra. A different nucleation mechanism was found depending on the nature of the oxide acting as substrate. The superior performance of the zinc oxide based low emissive coatings is related with a better wetting of silver on the surface of this oxide despite the comparatively lower roughness of the tin oxide layers.

Keywords: ZnO and SnO; ₂; thin films; Silver nucleation and wetting; Low emissivity coatings; Roughness evolution; Growth mechanism

Ion irradiation induced solid-state amorphous reaction in Ni/Ti multilayers by Momir Milosavljević; Dragan Toprek; Marko Obradović; Ana Grce; Davor Peruško; Goran Dražič; Janez Kovač; Kevin P. Homewood (pp. 516-523).

► 180keV Ar was implanted to 1–6×10¹⁶ions/cm² in (Ni 26nm/Ti 20nm)×5 multilayers. ► The intermixed phase is fully amorphous, starting from the initial stages. ► Continuous ∼127nm amorphous Ni₆₆Ti₃₄ layer is formed at high irradiation dose. ► The amorphous phase is not affected by further increase of the ion dose. ► The results can be interesting for studies of radiation tolerance of am-NiTi.The effects of Ar ion irradiation on interfacial reactions induced in Ni/Ti multilayers were investigated. Structures consisting of 10 alternate Ni (∼26nm) and Ti (∼20nm) layers of a total thickness ∼230nm were deposited by ion sputtering on Si (100) wafers. Argon irradiations were done at 180keV, to the doses of 1–6×10¹⁶ions/cm², the samples being held at room temperature. The projected implanted ion range is 86±36nm, maximum energy loss is closer to the surface, and maximum displacements per atom ( dpa) from 47 to 284 for Ni and 26 to 156 for Ti. Characterizations of samples were performed by transmission electron microscopy (TEM) and Rutherford backscattering spectrometry (RBS). It is shown that ion irradiation induced a progressed intermixing in the mostly affected zone already for the lowest dose, the thickness of the mix increasing linearly with the irradiation dose. The mixed phase is fully amorphous, starting with a higher concentration of Ni (which is the diffusing species) from the initial stages, and saturating at Ni:Ti∼66:34. A thick amorphous layer (∼127nm) formed towards the surface region of the structure for the irradiation dose of 4×10¹⁶ions/cm² remains stable with increasing the dose to 6×10¹⁶ions/cm², which introduces up to 6–7at.% of Ar within the mix. The results are discussed in light of the existing models. They can be interesting for introducing a selective and controlled solid-state reaction and towards further studies of ion irradiation stability of amorphous Ni–Ti phase.

Keywords: Ni/Ti multilayers; Amorphous Ni–Ti; Ion irradiation; Interfacial reactions

Size dependence of plasmon absorption of Ni nanoparticles embedded in BaTiO₃/SrTiO₃ superlattices by Zhengwei Xiong; Xiangrong Chen; Xuemin Wang; Liping Peng; Dawei Yan; Hongwen Lei; Yajun Fu; Jianbang Wu; Zhenli Li; Xinyou An; Weidong Wu (pp. 524-528).

► The nickel nanoparticles with different size were embedded in the barium titanate/strontium titanate superlattices. ► The increasing sizes and irregular shapes of nickel nanoparticles were observed as the increase of laser energy density. ► By the absorption spectra investigation, the absorption peak presented red-shift and broadening phenomenon with the increase of the sizes. ► The results were explained by the calculation of real and imaginary permittivity of bulk nickel.The self-organized nickel nanoparticles deposited with different laser energy densities were embedded in barium titanate/strontium titanate superlattices using laser molecular beam epitaxy. The increasing sizes and irregular shapes of nickel nanoparticles were observed as the increase of laser energy density. By the absorption spectra investigation, the absorption peak presented red-shift and broadening phenomenon with the increase of the sizes. The results were explained by the calculation of real and imaginary permittivity of bulk nickel.

Keywords: Laser molecular beam epitaxy; Reﬂection high-energy electron diffraction; Nanocrystals

Mold-free fabrication of 3D microfeatures using laser-induced shock pressure by Balasubramanian Nagarajan; Sylvie Castagne; Zhongke Wang (pp. 529-534).

► A new microfabrication technique for the formation of microfeatures on metal foils without the micromolds is proposed. ► Forming of craters on copper foils achieved using a flexible-pad and laser-induced plasma shock pressure. ► Different microfeature sizes are obtained by varying the laser fluence. ► Short process cycle time and improved flexibility due to the elimination of micromolds in microforming.This paper reports on the fabrication of microfeatures on metallic foils using laser-induced shock forming without the assistance of micromold patterns. A mold-free laser shock forming technique, Flexible Pad Laser Shock Forming (FPLSF) has been developed and demonstrated to fabricate near-spherical microcraters on thin copper foils through the laser-generated plasma shock inducing plastic deformation on the copper foil. It is found that the crater formation strongly depends on the laser energy fluence applied to ablate an ablative overlay which is on top of the copper foil for plasma shock generation. Microfeatures with deformation depth of 80μm to130μm and radius of 485μm to 616μm were formed on 25μm thick copper foils for the laser fluence of 7.3J/cm² to 20J/cm² while using aluminum foil as the ablative overlay and silicone rubber as a flexible support instead of a micromold. Fabrication of crater arrays on copper foils was also demonstrated successfully.

Keywords: Microforming; Laser-induced shock loading; Flexible pad forming; Thin metal foils

Mold-free fabrication of 3D microfeatures using laser-induced shock pressure by Balasubramanian Nagarajan; Sylvie Castagne; Zhongke Wang (pp. 529-534).

Keywords: Microforming; Laser-induced shock loading; Flexible pad forming; Thin metal foils

The characterization of CrCe-doped on TiO₂-pillared clay nanocomposites for NO oxidation and the promotion effect of CeO_x by Jingxin Zhang; Shule Zhang; Wei Cai; Qin Zhong (pp. 535-540).

► CrCe/TiO₂-pillared clay was newly introduced to the oxidation of NO. ► The CrCe/TiO₂-pillared clay nanocomposites were synthesized. The nanoparticles were round-shaped and average particle size was less than 10nm. ► Analysis of XPS indicated that the addition of ceria oxides could promote the formation of chemisorbed oxygen and raise the quantivalency of Cr. ► Through our research, we could find that the deactivation of the Cr based catalysts in SO₂ and H₂O was not totally irreversible.A series of chromium-ceria doped on TiO₂-pillared clay nanocomposites catalysts with various Cr/Ce ratios were investigated in the oxidation of NO. This study aimed to not only synthesize the CrCe/TiO₂-PILC nanocomposites, but also figure out the promotion effect of Ce in the oxidation process and the interaction between chromium and ceria on the surface of TiO₂-PILC. The samples were characterized by XRD, SEM, TEM, XPS and H₂-TPR methods. The best catalyst Cr(1)Ce(0.25)/TiO₂-pillared clay yielded 69% NO to NO₂ conversion at 350°C (in the condition of GHSV=35,400h⁻¹). With the content of ceria increasing, the NO conversion increased significantly while when the Cr/Ce equaled 1:1, the activity decreased. The chromium oxides were well dispersed on the surface of the support. Analysis of XPS indicated that the addition of ceria oxides could promote the formation of chemisorbed oxygen and raise the quantivalency of Cr. The powerful electron withdrawing ability of Ce made the electron density around Ti atoms decrease. The result showed that CeO_x enhanced the metal–support interaction. H₂-TPR indicated that the proper addition of CeO_x increased the reducible phase that was beneficial to the reaction. Moreover, the catalysts showed a good resistance to SO₂ and H₂O. When SO₂ and H₂O were added in the feed gas, the catalytic activity decreased but when removed, the activity recovered. The deactivation was not totally irreversible.

Keywords: Selective catalytic oxidation; Chromium oxide; Ceria doping; TiO; ₂; -pillared clay nanocomposites

The characterization of CrCe-doped on TiO₂-pillared clay nanocomposites for NO oxidation and the promotion effect of CeO_x by Jingxin Zhang; Shule Zhang; Wei Cai; Qin Zhong (pp. 535-540).

Keywords: Selective catalytic oxidation; Chromium oxide; Ceria doping; TiO; ₂; -pillared clay nanocomposites

A green and efficient method to produce graphene for electrochemical capacitors from graphene oxide using sodium carbonate as a reducing agent by Yuhong Jin; Shuo Huang; Mei Zhang; Mengqiu Jia; Dong Hu (pp. 541-546).

We use Na₂CO₃ as a new chemical reducing agent for the reduction of GO dispersion. Na₂CO3 can produce and yield the hydroxide ions in the aqueous solution. Graphene oxide can be deoxygenated under alkaline condition. Specific capacitance values as high as 228Fg⁻¹ have been demonstrated with KOH electrolyte.Display Omitted► A green and efficient synthesis of graphene sheets using sodium carbonate (Na₂CO₃) as a chemical reducing agent was studied. ► The possible mechanism for the deoxygenation reaction of graphene oxide was demonstrated. ► Extensive characterization showed that as-prepared materials consisted of few-layer thick graphene. ► The electrocapacitive performance of the Na₂CO₃-reduced graphene oxide was better than that of the hydrazine or NaBH₄-reduced graphene.The green and efficient synthesis of graphene using sodium carbonate (Na₂CO₃) as a chemical reducing agent was studied. Extensive characterization confirmed the formation of graphene from graphene oxide using a Na₂CO₃ solution. The C/O atomic ratio of the as-prepared graphene has increased from 2.48 to 8.15 after reduction as determined by X-ray photoelectron spectroscopy. The conductivity of as-prepared graphene sheets is as high as 10Sm⁻¹. After electrochemical measurements, gravimetric capacitances of 228 and 166Fg⁻¹ at current densities of 5 and 25mAcm⁻², respectively, were obtained with KOH electrolyte.

Keywords: Sodium carbonate; Graphene oxide; Graphene; Electrochemical capacitors

Surface modification of hydroturbine steel using friction stir processing by H.S. Grewal; H.S. Arora; H. Singh; A. Agrawal (pp. 547-555).

► Friction stir processing (FSP) of CA6NM steel was successfully attempted. ► Microstructure of the steel was refined with 10 folds reduction in grain size. ► EBSD results confirmed variable texture across the stir zone. ► FSPed CA6NM steel showed 2.6 times improvement in hardness. ► Cavitation erosion resistance of steel was enhanced by 2.4 times after FSP.Friction stir processing (FSP) has proved to be a viable tool for enhancing the mechanical properties of materials, however, the major focus has been upon improving the bulk properties of light metals and their alloys. Hydroturbines are susceptible to damage owing to slurry and cavitation erosion. In this study, FSP of a commonly employed hydroturbine steel, 13Cr4Ni was undertaken. Microstructural characterization of the processed steel was conducted using optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and electron back scatter diffraction (EBSD) techniques. Mechanical characterization of the steel was undertaken in terms of microhardness and resistance to cavitation erosion (CE). FSP resulted in the refinement of the microstructure with reduction in grain size by a factor of 10. EBSD results confirmed the existence of submicron and ultrafine grained microstructure. The microhardness of the steel was found to enhance by 2.6 times after processing. The processed steel also showed 2.4 times higher resistance against cavitation erosion in comparison to unprocessed steel. The primary erosion mechanism for both the steels was identical in nature, with plastic deformation responsible for the loss of material.

Keywords: Thermo-mechanical processing; Steel; Ultrafine grained material; EBSD

Surface modification of hydroturbine steel using friction stir processing by H.S. Grewal; H.S. Arora; H. Singh; A. Agrawal (pp. 547-555).

Keywords: Thermo-mechanical processing; Steel; Ultrafine grained material; EBSD

Effect of annealing temperature on thermochromic properties of vanadium dioxide thin films deposited by organic sol–gel method by Jing Wu; Wanxia Huang; Qiwu Shi; Jinghan Cai; Dong Zhao; Yubo Zhang; Jiazhen Yan (pp. 556-560).

► The inexpensive raw materials are utilized to prepare sol. ► The lipophilic organic solvents are rapidly spreading out on mica substrate. ► The process is simple that could achieve briefly. ► Annealing temperature is lower than other methods. ► The VO₂ thin films have good properties.This paper described the synthesis of vanadium dioxide (VO₂) thin films on mica substrates with different annealing temperatures by an organic sol–gel method. We performed X-ray diffraction, scanning electron microscope and optical transmission measurements to investigate the effect of the annealing temperature on the crystalline structure, morphology, and phase transition properties of these films. The results showed that a polycrystalline structure with high crystallinity and compact surface at the annealing temperature of 500°C. The film exhibited a V₆O₁₃ phase and a flat surface with small grain size at 440°C. By contrast, the V_nO2 n₋₁ appeared when the annealing temperature at 540°C, and the film surface split into segregation of spherical grain and aggregates of continuously dendritic particles. Accordingly, the optimal annealing temperature was 500°C using the organic sol–gel method. And it turned out that the films mainly contained VO₂ (M) phase at room temperature with high content of V⁴⁺ valence. Particularly, the films showed different changes in the infrared transmittance and hysteresis width during the phase transition. The largest transformation of the infrared transmittance before and after MIT was 73%, while the narrowest temperature hysteresis width was 8°C at 500°C.

Keywords: Organic sol; VO; ₂; thin films; Thermochromic; Annealing temperature

Synthesis of rod-cluster ZnO nanostructures and their application to dye-sensitized solar cells by Yongming Meng; Yu Lin; Jiyuan Yang (pp. 561-565).

► Rod-cluster ZnO nanostructures were synthesized by a simple hydrothermal route. ► The effects of reaction conditions on the morphologies had been investigated. ► The effects of reaction conditions on the performances of cells had been studied. ► The cell shows a higher power conversion efficiency of 2.42%.This paper reports a simple hydrothermal route for the preparation of rod-cluster ZnO nanostructures and their application to dye-sensitized solar cells. The effects of reaction conditions on the morphologies of ZnO nanostructures and the performance of cells had been investigated including hydrothermal temperature, time and pH value of the reaction solution. The product synthesized with pH=10 of the reacting solution at 120°C for 18h comparatively shows the best photoelectric conversion efficiency of 2.42% on the basis of its structural superiority for light capture and dye absorption.

Keywords: Hydrothermal route; Rod-cluster ZnO nanostructures; Dye-sensitized solar cell

Synthesis of rod-cluster ZnO nanostructures and their application to dye-sensitized solar cells by Yongming Meng; Yu Lin; Jiyuan Yang (pp. 561-565).

Keywords: Hydrothermal route; Rod-cluster ZnO nanostructures; Dye-sensitized solar cell

Adsorption properties of biomass-based activated carbon prepared with spent coffee grounds and pomelo skin by phosphoric acid activation by Xiaodong Ma; Feng Ouyang (pp. 566-570).

► AC prepared from coffee grounds and pomelo skin were activated by phosphoric acid. ► Adsorption of ethylene and n-butane fitted well with Langmuir equation at 308K. ► PS-AC could adsorb 129cm³/g n-butane at room temperature up to 1atm. ► Micropore filling effect was explained in a thermodynamic way.Activated carbon prepared from spent coffee grounds and pomelo skin by phosphoric acid activation had been employed as the adsorbent for ethylene and n-butane at room temperature. Prepared activated carbon was characterized by means of nitrogen adsorption–desorption, X-ray powder diffraction, scanning electron microscope and Fourier transform infrared spectroscope. It was confirmed that pore structure played an important role during the adsorption testes. Adsorption isotherms of ethylene and n-butane fitted well with Langmuir equation. The prepared samples owned better adsorption capacity for n-butane than commercial activated carbon. Isosteric heats of adsorptions at different coverage were calculated through Clausius–Clapeyron equation. Micropore filling effect was explained in a thermodynamic way.

Keywords: Activated carbon; Coffee grounds; Pomelo skin; Adsorption

Adsorption properties of biomass-based activated carbon prepared with spent coffee grounds and pomelo skin by phosphoric acid activation by Xiaodong Ma; Feng Ouyang (pp. 566-570).

Keywords: Activated carbon; Coffee grounds; Pomelo skin; Adsorption

Rutile microtubes assembly from nanostructures obtained by ultra-short laser ablation of titanium in liquid by A. De Bonis; A. Galasso; N. Ibris; A. Laurita; A. Santagata; R. Teghil (pp. 571-578).

► Laser ablation of a titanium target in water performed by an ultra-short laser source has been reported. ► The formation of nonstoichiometric titanium oxide nanoparticles has been observed. ► The titanium oxide nanoparticles give rise to different nano and micro-structure in a water driven process.Pulsed laser ablation of a titanium target in water was performed by an ultra-short laser source (Ti-sapphire, λ=800nm, 1kHz, 100fs). The obtained structures were characterized by atomic force microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, micro-Raman spectroscopy and X-ray diffraction, revealing the presence of non-stoichiometric titanium oxide nanoparticles with a certain amount of crystalline rutile phase. Upon remaining in water the ablated species, the formation of a lamellar phase has been observed. This lamellar phase rolls up to microtubes by remaining in water for a month, through a self-assembling process. The formed microtubes, with an inner diameter of about 2μm and an outer diameter of 4μm are characterized by a smooth interior surface and aggregation of nanoparticles on the outer surface.

Keywords: Microtubes; Rutile; Ultrashort laser pulses; LAL

Rutile microtubes assembly from nanostructures obtained by ultra-short laser ablation of titanium in liquid by A. De Bonis; A. Galasso; N. Ibris; A. Laurita; A. Santagata; R. Teghil (pp. 571-578).

Keywords: Microtubes; Rutile; Ultrashort laser pulses; LAL

Microstructure and water-lubricated friction and wear properties of CrN(C) coatings with different carbon contents by Qianzhi Wang; Fei Zhou; Xiangdong Ding; Zhifeng Zhou; Chundong Wang; Wenjun Zhang; Lawrence Kwok-Yan Li; Shuit-Tong Lee (pp. 579-587).

► CrN(C) coatings with different C content were synthesized on 316L stainless steel. ► The hardness of CrN(C) coatings deposited at 1A increased to 22.5GPa. ► The sp²CN, sp³CN and CrC bonds were formed in CrN(C) coatings. ► The CrN(C) coatings deposited at 1A exhibited the lowest friction coefficient. ► The CrN(C) coatings lowered the wear rates of Si₃N₄ balls compared with CrN coatings.The CrN(C) coatings with different carbon contents were deposited using unbalanced magnetron sputtering via adjusting the carbon target current, and their microstructure and mechanical properties were characterized using Raman spectrum, X-ray photoelectron spectroscopy and nano-indenter, respectively. The water-lubricated tribological properties of the CrN(C) coatings against Si₃N₄ balls were investigated using the ball-on-disk tribometer. The results showed that the C content in the CrN(C) coatings increased gradually, and the peak intensity correlated to Cr₇C₃ crystal phase became stronger when the carbon target current increased. When the carbon target current was 1A, the hardness of the CrN(C) coatings increased to 22.5GPa due to formation of Cr₇C₃ phase and amorphous CN_x, and a little amorphous carbon had positive effect on tribological properties of the CrN(C) coatings in water lubrication. On the other hand, CrN(C) coatings deposited at 2–4A exhibited a lower hardness and deteriorated tribological properties, due to the presence of a major amount of Cr₂O₃ particles in the films.

Keywords: Thin films; Sputtering; X-ray diffraction; Photoelectron spectroscopy; Mechanical properties

Synthesis of metal-incorporated graphitic microporous carbon terminated with highly-ordered graphene walls—Controlling the number of graphene layers by ambient-temperature metal sputtering by Arghya Narayan Banerjee; Bong-Ki Min; Sang Woo Joo (pp. 588-600).

► Graphitic microporous carbon from amorphous carbon by metal sputtering text was fabricated. ► Multilayer graphene is formed via nanoparticle/ion bombardment at room temperature. ► The number of graphene layer formation is controlled by sputtering parameters ► Sputtering plasma manifests activation via dry-etching. ► Energy distribution of sputtered atoms/ions show knock-on effect for graphitization.Metal-incorporated, graphitic microporous carbon, containing highly ordered graphene layers, has been converted from highly thin amorphous carbon film by a metal nanoparticle sputtering process at ambient substrate temperature. A standard direct-current magnetron sputtering system is used in this purpose. The process consists of a dual effect of activation and graphitization of amorphous carbon to graphitic microporous carbon. The sputtering plasma, containing energetic ions and sub-atomic particles, act as dry-etchant to activate the a:C film to transform it into microporous carbon. Whereas, the inelastic ‘knock-on’ collision between metal nanoparticles/ions and the nuclei of C atoms manifests the atom displacement and re-arrangement into ordered structure to form graphitic domains within the microporous carbon network. The average number of graphene layer formation has been controlled by adjusting the sputtering voltage and current, as the carbon atom displacement rate is dependent on the irradiation current density. Raman spectroscopy and scanning transmission electron microscopy confirms the high controllability of the number of graphene layer formation as a function of sputtering parameters. The method is simple, cost-effective and compatible with modern solid-state device fabrication processing, as it comprises vacuum-based physical vapor deposition techniques, and also, can be adopted easily for transitional metal incorporation into graphene and other carbon nanostructures for potential hydrogen storage and related clean energy applications.

Keywords: Few-to-multilayer graphene; Knock-on collision; Ambient temperature; Metal nanoparticle sputtering; CMOS-compatible; Hydrogen storage

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Applied Surface Science (v.268, #)