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Applied Surface Science (v.257, #6)

Editorial Board (pp. ii).

Surface bioactivity modification of titanium by CO₂ plasma treatment and induction of hydroxyapatite: In vitro and in vivo studies by Xixue Hu; Hong Shen; Kegang Shuai; Enwei Zhang; Yanjie Bai; Yan Cheng; Xiaoling Xiong; Shenguo Wang; Jing Fang; Shicheng Wei (pp. 1813-1823).

Since metallic biomaterials used for orthopedic and dental implants possess a paucity of reactive functional groups, bioactivity modification of these materials is challenging. In the present work, the titanium discs and rods were treated with carbon dioxide plasma and then incubated in a modified simulated body fluid 1.5SBF to obtain a hydroxyapatite layer. Surface hydrophilicity of samples, changes of surface chemistry, surface morphologies of samples, and structural analysis of formed hydroxyapatite were investigated by contact angle to water, X-ray photoelectron spectrometer (XPS), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) and X-ray diffraction (XRD). The results demonstrated that hydrophilicity of titanium surface was improved and hydroxyl groups increased after modification with carbon dioxide plasma treatment. The hydroxyl groups on the surface of titanium were the richest after carbon dioxide plasma treatment under the condition of 20W for less than 30s. The hydroxyapatite formability of titanium surface was enhanced by carbon dioxide plasma pretreatment, which was attributed to the surface chemistry. MC3T3-E1 cell as a model cell was cultured on the Ti, CPT-Ti and CPT/SBF-Ti discs in vitro, and the results of the morphology and differentiation of the cell showed that CPT/SBF-Ti was the highest bioactive. The relative parameters of the new bone around the Ti and CPT/SBF-Ti rods including bone mineral density (BMD), a ratio of bone volume to total volume (BV/TV), trabecular thickness (Tb.Th.) and trabecular number (Tb.N.) were analyzed by a micro-computed tomography (micro-CT) after 4-, 8- and 12-week implantation periods in vivo. The results indicated that the CPT/SBF-Ti was more advantageous for new bone formation.

Keywords: Titanium; Surface modification; Carbon dioxide plasma; Hydroxyapatite; Bioactivity

Low thermal emissive surface properties of ZnO/polyimide composites prepared by pulsed laser deposition by H.A. Babrekar; S.M. Jejurikar; J.P. Jog; K.P. Adhi; S.V. Bhoraskar (pp. 1824-1828).

We report the low thermal-emissive surface properties of composites of ZnO–polyimide. The composites were synthesized by depositing ZnO on polyimide surface by pulsed laser deposition technique. ZnO target was ablated at different incident energy densities and the substrate (polyimide) was held at elevated temperature. This facilitated the c-axis oriented growth of ZnO, which was inferred from the X-ray diffraction analysis. The composites consisted of multilayers having different electrical resistivities. The values of which are also estimated from Hagen–Rubens relation. The reduced infrared emissivities of the composite films, as compared to polyimide, were correlated to the increased carrier concentration and reduced surface resistivity estimated from the Hall measurements.

Keywords: PACS; 81.15.Fg; 81.05.Qk; 77.55.hf; 78.20.CiPulsed laser deposition; Thermal emissivity; Thin films; Zinc oxide

Low thermal emissive surface properties of ZnO/polyimide composites prepared by pulsed laser deposition by H.A. Babrekar; S.M. Jejurikar; J.P. Jog; K.P. Adhi; S.V. Bhoraskar (pp. 1824-1828).

Keywords: PACS; 81.15.Fg; 81.05.Qk; 77.55.hf; 78.20.CiPulsed laser deposition; Thermal emissivity; Thin films; Zinc oxide

Influence of pre-surface treatment on the morphology of silicon nanowires fabricated by metal-assisted etching by Shu-Chia Shiu; Shin-Bo Lin; Shih-Che Hung; Ching-Fuh Lin (pp. 1829-1834).

Herein we demonstrate an improved metal-assisted etching method to achieve highly dense and uniform silicon nanowire arrays. A pre-surface treatment was applied on a silicon wafer before the process of metal-assisted etching in silver nitrate and hydrogen fluoride solution. The treatment made silver ion continuously reduce on silver nuclei adherence on the silicon surface, leading to formation of dense silver nanoparticles. Silver nanoparticles acting as local redox centers cause the formation of dense silicon nanowire arrays. In contrast, an H-terminated silicon surface made silver ion reduce uniformly on the silicon surface to form silver flakes. The silicon nanowires fabricated with a pre-surface treatment reveals higher density than those fabricated without a pre-surface treatment. The volume fraction improves from 18 to 38%. This improvement reduces the solar-weighted reflectance to as low as 3.3% for silicon nanowires with a length of only 0.87μm. In comparison, the silicon nanowires fabricated without a pre-surface treatment have to be as long as 1.812μm to achieve the same reflectance.

Keywords: Silicon nanowire; Metal-assisted etching; Pre-surface treatment; Antireflection

Influence of pre-surface treatment on the morphology of silicon nanowires fabricated by metal-assisted etching by Shu-Chia Shiu; Shin-Bo Lin; Shih-Che Hung; Ching-Fuh Lin (pp. 1829-1834).

Keywords: Silicon nanowire; Metal-assisted etching; Pre-surface treatment; Antireflection

Effect of different alloyed layers on the high temperature oxidation behavior of newly developed Ti₂AlNb-based alloys by Hongyan Wu; Pingze Zhang; Haofeng Zhao; Ling Wang; Aigen Xie (pp. 1835-1839).

The application of titanium aluminide orthorhombic alloys (O-phase alloys) as potential materials in aircraft and jet engines was limited by their poor oxidation resistance at high temperature. The Ti₂AlNb-based alloys were chromised (Cr), chromium–tungstened (Cr–W) and nickel–chromised (Ni–Cr) by the double glow plasma surface alloying process to improve their high temperature oxidation resistance. The discontinuous oxidative behavior of Cr, Cr–W and Ni–Cr alloyed layers on Ti₂AlNb-based alloy at 1093K was explored in this study. After exposing at 1093K, the TiO₂ layer was formed on the bare alloy and accompanied by the occurrence of crack, which promoted oxidation rate. The oxidation behavior of Ti₂AlNb-based alloys was improved by surface alloying due to the formation of protective Al₂O₃ scale or continuous and dense NiCr₂O₄ film. The Ni–Cr alloyed layer presented the best high-temperature oxidation resistance among three alloyed layers.

Keywords: Oxidation resistance; Orthorhombic alloys; Plasma surface alloying

Effect of the molecular weight of sizing agent on the surface of carbon fibres and interface of its composites by R.L. Zhang; Y.D. Huang; L. Liu; Y.R. Tang; D. Su; L.W. Xu (pp. 1840-1844).

The influence of different molecular weight sizing agent on the performances of carbon fibres and carbon fibres composites were studied. Three different kinds of molecular weight sizing were used. Surface composition of the fibres modified with aqueous sizing and topographies of carbon fibres surface were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and scanning electron microscope (SEM). The interlaminar shear strength and hygrothermal ageing test have been used to study the effect of fibres coatings on the adhesion of surface. The results of the study indicate that the molecular weight of sizing agent has an important influence to the carbon fibres and carbon fibres composites. The high and low molecular weight sizing agent decreased the interfacial shear strengths and hygrothermal ageing of carbon fibres composite. The moderate molecular weight of sizing agent showed an improvement of the interfacial adhesion and hygrothermal ageing.

Keywords: Carbon fibres; Interfacial strength; Coating; Hygrothermal effect

Effect of the molecular weight of sizing agent on the surface of carbon fibres and interface of its composites by R.L. Zhang; Y.D. Huang; L. Liu; Y.R. Tang; D. Su; L.W. Xu (pp. 1840-1844).

Keywords: Carbon fibres; Interfacial strength; Coating; Hygrothermal effect

Mild hydrothermal treatment to prepare highly dispersed multi-walled carbon nanotubes by Li Zhang; Yoshio Hashimoto; Toshinori Taishi; Qing-Qing Ni (pp. 1845-1849).

Multi-walled carbon nanotubes (MWCNTs) with improved dispersion property have been prepared by a mild and fast hydrothermal treatment. The hydrothermal process avoids using harsh oxidants and organic solvents, which is environmental friendly and greatly decreases the damage to intrinsic structure of MWCNTs. The modified MWCNTs were highly soluble in polar solvents such as water, ethanol and dimethylformamide. Morphological observation by TEM indicated that the diameter and inherent structure were well reserved in modified MWCNTs. X-ray photoelectron spectroscopy and Raman spectroscopy were used to quantify functional groups created on the MWCNT surface, and to determine rational parameters of hydrothermal process.

Keywords: Multi-walled carbon nanotubes; Hydrothermal treatment; Improved dispersion property

Mild hydrothermal treatment to prepare highly dispersed multi-walled carbon nanotubes by Li Zhang; Yoshio Hashimoto; Toshinori Taishi; Qing-Qing Ni (pp. 1845-1849).

Keywords: Multi-walled carbon nanotubes; Hydrothermal treatment; Improved dispersion property

Effect of substrate bias and temperature on magnetron sputtered CrSiN films by Shuyong Tan; Xuhai Zhang; Xiangjun Wu; Feng Fang; Jianqing Jiang (pp. 1850-1853).

The combine influence of substrate temperature and bias on microstructure and mechanical properties of CrSiN film was examined. The silicon content and phase constitutions of the films are independent on substrate temperature and bias. The crystal preferred orientation is controlled by substrate bias but unrelated to substrate temperature. The influence of bias (0V to −300V) on hardness is more obvious than that of the substrate temperature (100–500°C).

Keywords: CrSiN film; DC magnetron sputtering; Substrate bias; Substrate temperature

Effect of substrate bias and temperature on magnetron sputtered CrSiN films by Shuyong Tan; Xuhai Zhang; Xiangjun Wu; Feng Fang; Jianqing Jiang (pp. 1850-1853).

Keywords: CrSiN film; DC magnetron sputtering; Substrate bias; Substrate temperature

Enhanced field emission characteristics of boron doped diamond films grown by microwave plasma assisted chemical vapor deposition by Pankaj M. Koinkar; Sandip S. Patil; Tae-Gyu Kim; Daisuke Yonekura; Mahendra A. More; Dilip S. Joag; Ri-ichi Murakami (pp. 1854-1858).

Boron doped diamond films were synthesized on silicon substrates by microwave plasma chemical vapor deposition (MPCVD) technique. The effect of B₂O₃ concentration varied from 1000 to 5000ppm on the field emission characteristics was examined. The surface morphology and quality of films were characterized by scanning electron microscope (SEM) and Raman spectroscopy. The surface morphology obtained by SEM showed variation from facetted microcrystal covered with nanometric grains to cauliflower of nanocrystalline diamond (NCD) particles with increasing B₂O₃ concentration. The Raman spectra confirm the formation of NCD films. The field emission properties of NCD films were observed to improve upon increasing boron concentration. The values of the onset field and threshold field are observed to be as low as 0.36 and 0.08V/μm, respectively. The field emission current stability investigated at the preset value of ∼1μA is observed to be good, in each case. The enhanced field emission properties are attributed to the better electrical conductivity coupled with the nanometric features of the diamond films.

Keywords: CVD diamond; Boron doping; Field emission; Raman spectroscopy

Effect of alkaline cleaning and activation on aluminum alloy 7075-T6 by Simon Joshi; William G. Fahrenholtz; Matthew J. O’Keefe (pp. 1859-1863).

The effect of alkaline cleaning and activation on the composition and thickness of the oxide layer on aluminum alloy 7075-T6 was studied. E–pH diagrams were developed to predict the effect of alkaline cleaning and activation solutions on the stability of the oxide surface layers. The thickness of the native oxide layer was determined to be ∼30nm by Auger electron spectroscopy depth profiling analysis. The outer ∼20nm was rich in magnesium while the remaining ∼10nm was rich in aluminum. Cleaning in a 9.1 pH alkaline solution was found to remove the magnesium-rich layer and leave behind an aluminum-rich oxide layer ∼10nm thick. Activation in alkaline solutions of NaOH (pH>12.9) or Na₂CO₃ (pH>11.5) produced an oxide that was ∼20 to 60nm thick and rich in magnesium. Alkaline cleaning and activation altered the oxide composition and thickness making it possible for deposition of thicker cerium-based conversion coatings (∼100 to 250nm) compared to only alkaline cleaning (∼30nm), with application of one spray cycle of deposition solution.

Keywords: Aluminum; Magnesium; Oxide; NaOH; Na; ₂; CO; ₃; Degreasing

Effect of alkaline cleaning and activation on aluminum alloy 7075-T6 by Simon Joshi; William G. Fahrenholtz; Matthew J. O’Keefe (pp. 1859-1863).

Keywords: Aluminum; Magnesium; Oxide; NaOH; Na; ₂; CO; ₃; Degreasing

Unusual photo-induced adsorption–desorption behavior of propylene on Ag/TiO₂ nanotube under visible light irradiation by Caixia Feng; Jingwei Zhang; Rui Lang; Zhensheng Jin; Zhishen Wu; Zhijun Zhang (pp. 1864-1870).

Titanium dioxide (TiO₂) nanotube with a large amount of single-electron-trapped-oxygen-vacancies (coded as T2) was obtained by annealing nanotube H₂Ti₂O₄(OH)₂ (coded as T1) at 400°C in air. Silver nanoparticles with a diameter of about 30–50nm were loaded onto the surface of T2 via deposition associated with photochemical reduction under ultraviolet irradiation. The resulting Ag/TiO₂ nanotube (coded as T3) was characterized by means of transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and ultraviolet–visible light diffusion reflectance spectrometry. It was found that C₃H₆ experienced unusual photo-induced adsorption–desorption on T3 under visible light irradiation. Namely, C₃H₆ was initially desorbed from T3 and then adsorbed on T3 under visible light irradiation. On the contrary, C₃H₆ was initially adsorbed on T3 in the dark, followed by desorption. The reason might lie in that two kinds of active sites exist on the surface of T3, corresponding to quite different rates of adsorption and desorption. It was found that oxygen vacancies in association with deposited silver particles, were responsible for the alternative adsorption–desorption of C₃H₆ on T3.

Keywords: Ag/TiO; ₂; nanotube; Visible light irradiation; Oxygen vacancy; Propylene; Adsorption; Desorption

Surface treatment of barium gallogermanate laser glass by Gang Yang; Qi Qian; Zhongmin Yang (pp. 1871-1875).

The surface of barium gallogermanate glass is modified through HCl solution etching to remove the surface defects and contaminations. The etching process and mechanism for barium gallogermanate glass in hydrochloric acid are investigated, and its optimum conditions are determined. However, the HCl etching induces the insoluble etch product containing minute crystal particles on glass surface. By heating BGG glass at the optical fiber drawing temperature, the deposited surface layer turned to be amorphous again and results in the increase of the transmittance of glass. The results indicated that the HCl etching combined with subsequent high-temperature heat treatment is an effective approach to improve the surface quality of barium gallogermanate glass, which would reduce the optical loss of the final optical fiber.

Keywords: Barium gallogermanate glass fiber; Surface; Chemical etching; Heating treatment

Surface treatment of barium gallogermanate laser glass by Gang Yang; Qi Qian; Zhongmin Yang (pp. 1871-1875).

Keywords: Barium gallogermanate glass fiber; Surface; Chemical etching; Heating treatment

Effects of rare earth and tantalum on graphite-like carbon coatings by Zuo-ping Wang; Zhong-wei Ma; Peng-bo Chen; Jian-dong Xing; Hai-lin Sun (pp. 1876-1880).

The graphite-like carbon (GLC) coating with low friction and good wear resistance is appreciable to make further improvement. Ce, Y and Ta are doped into GLC by using mosaic in the target of magnetron sputtering process. The result shows that yttrium composed in chromium interlayer can increase the bonding strength and refine the microstructure of the GLC coating. For the surface layer of GLC, incorporation of Ta improves wear resistance and deposition rate, in the mean time the friction coefficient is decreased. As the modifications of interlayer and top layer are composed together to form complex GLC coating, the specific wear rate is reduced and the hardness, bonding strength and anti corrosion behavior are improved.

Keywords: Rare earth; Tantalum; Magnetron sputtering; Graphite-like carbon coatings

Effects of rare earth and tantalum on graphite-like carbon coatings by Zuo-ping Wang; Zhong-wei Ma; Peng-bo Chen; Jian-dong Xing; Hai-lin Sun (pp. 1876-1880).

Keywords: Rare earth; Tantalum; Magnetron sputtering; Graphite-like carbon coatings

Uptake of hydrogen from some carbon fibres examined by Secondary Ion Mass Spectrometry by A. Madroñero; J. Aguado; J.M. Blanco; A. López (pp. 1881-1885).

The use of carbonaceous materials for hydrogen storage is not as simple as it may seem. Hydrogen atoms have different bonding energies and are incorporated into different types of these materials. Therefore, it is particularly important to distinguish between the surfacial atoms and those that are embedded in the bulk of the sample.SIMS spectrograph with periodical interruptions of the ion beam enables us to appreciate that at room temperature and in high vacuum, some outgassing of the surfacial hydrogen takes place.

Keywords: Hydrogen adsorption; Hydrogen storage; SIMS hydrogen determination; Carbon microfibres outgassing; Hydrogen ejection by vacuum

Uptake of hydrogen from some carbon fibres examined by Secondary Ion Mass Spectrometry by A. Madroñero; J. Aguado; J.M. Blanco; A. López (pp. 1881-1885).

Keywords: Hydrogen adsorption; Hydrogen storage; SIMS hydrogen determination; Carbon microfibres outgassing; Hydrogen ejection by vacuum

Thiolated cyclodextrin self-assembled monolayer-like characterized with secondary ion mass spectrometry by L. Rabara; M. Aranyosiova; D. Velic (pp. 1886-1892).

In the work the focus is on the preparation of self-assembled monolayer-like films consisting of thiolated cyclodextrin on gold substrate and a characterization by using secondary ion mass spectrometry. The short (1min) and long (1h) time preparations of self-assembled monolayer-like films, resulting in submonolayer and monolayer regimes, are investigated, respectively. The observed species of thiolated cyclodextrin (M as molecular ion) self-assembled monolayer-like films are assigned to three groups: Au_xH_yS_z clusters, fragments with origin in cyclodextrin molecule associated with Au, and molecular ions. The group of Au_xH_yS_z ( x=2–17, y=0–2, z=1–5) clusters have higher intensities than other species in the positive and even more in negative mass spectra. Interestingly, the dependence between the number of Au and S atoms shows that with the increasing size of Au_xH_yS_z clusters up to 11 Au atoms, the number of associated S atoms is also increasing and then decreasing. Molecular species as (M−S+H)Na⁺, (M+H)Na⁺, AuMNa⁺, (M₂−S)Na⁺, and M₂Na⁺ are determined, and also in cationized forms with K⁺. The intensities of thiolated cyclodextrin fragments at the long time preparation are approximately 10 times higher than the intensities of the same fragments observed at the short time. The largest observed ions in thiolated cyclodextrin self-assembled monolayer-like films are AuM₂ and Au₂M. The thiolated cyclodextrin molecular ions are compared with hexadecanethiol molecular ions in the form of Au_xM_w where the values of x and w are smaller for thiolated cyclodextrin than for hexadecanethiol. This result is supported with larger, more compact, and more stabile thiolated cyclodextrin molecule.

Keywords: Key words; ToF-SIMS; Thiolated cyclodextrin; Gold film; SAM

Thiolated cyclodextrin self-assembled monolayer-like characterized with secondary ion mass spectrometry by L. Rabara; M. Aranyosiova; D. Velic (pp. 1886-1892).

Keywords: Key words; ToF-SIMS; Thiolated cyclodextrin; Gold film; SAM

Determination of photocatalytic activity in amorphous and crystalline titanium oxide films prepared using plasma-enhanced chemical vapor deposition by Cheng-Yang Wu; Bo-Sheng Chiang; Springfield Chang; Day-Shan Liu (pp. 1893-1897).

Hydro-oxygenated amorphous titanium oxide (a-TiO_x:OH) films were prepared by plasma-enhanced chemical vapor deposition (PECVD) using precursors of titanium tetraisopropoxide (TTIP) and oxygen. The influences of chemical states and crystal quality on the photocatalytic activity were systematically investigated in the as-deposited and post-annealed films. The degree of the photocatalytic activity was deeply correlated with the porosity related to the hydroxyl (OH) groups in the as-deposited amorphous film. The crystallized anatase structures was observed from the 200°C-deposited a-TiO_x:OH film after a post-annealing treatment at 400°C. The photocatalytic activity related to the film with anatase structure was markedly superior to that of an amorphous film with porous structures. The larger the crystal size of the anatase structure, the higher the photocatalytic activity obtained. At elevated annealed temperatures, the inferior anatase structure due to the crystalline transformation led to a low photocatalytic activity. It was concluded that the photocatalytic activity of an amorphous TiO_x film prepared using PECVD was determined by the porosity originating from the functional OH groups in the film, whereas the crystalline quality of anatase phase in the annealed poly-TiO_x film was crucial to the photocatalytic activity.

Keywords: Hydro-oxygenated amorphous titanium oxide; Plasma-enhanced chemical vapor deposition; Photocatalytic activity; Porosity; Anatase phase

Nanostructured bioactive glass–ceramic coatings deposited by the liquid precursor plasma spraying process by Yanfeng Xiao; Lei Song; Xiaoguang Liu; Yi Huang; Tao Huang; Yao Wu; Jiyong Chen; Fang Wu (pp. 1898-1905).

Bioactive glass–ceramic coatings have great potential in dental and orthopedic medical implant applications, due to its excellent bioactivity, biocompatibility and osteoinductivity. However, most of the coating preparation techniques either produce only thin thickness coatings or require tedious preparation steps. In this study, a new attempt was made to deposit bioactive glass–ceramic coatings on titanium substrates by the liquid precursor plasma spraying (LPPS) process. Tetraethyl orthosilicate, triethyl phosphate, calcium nitrate and sodium nitrate solutions were mixed together to form a suspension after hydrolysis, and the liquid suspension was used as the feedstock for plasma spraying of P₂O₅–Na₂O–CaO–SiO₂ bioactive glass–ceramic coatings. The in vitro bioactivities of the as-deposited coatings were evaluated by soaking the samples in simulated body fluid (SBF) for 4h, 1, 2, 4, 7, 14, and 21 days, respectively. The as-deposited coating and its microstructure evolution behavior under SBF soaking were systematically analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), inductively coupled plasma (ICP), and Fourier transform infrared (FTIR) spectroscopy. The results showed that P₂O₅–Na₂O–CaO–SiO₂ bioactive glass–ceramic coatings with nanostructure had been successfully synthesized by the LPPS technique and the synthesized coatings showed quick formation of a nanostructured HCA layer after being soaked in SBF. Overall, our results indicate that the LPPS process is an effective and simple method to synthesize nanostructured bioactive glass–ceramic coatings with good in vitro bioactivity.

Keywords: Bioactive glass–ceramic; Coating; Liquid precursor; Plasma spraying; Nanostructure

Novel multilayered porous silicon-based immunosensor for determining Hydroxysafflor yellow A by Xiaoyi Lv; Jiaqing Mo; Tao Jiang; Furu Zhong; Zhenhong Jia; Jiangwei Li; Fuchun Zhang (pp. 1906-1910).

External random factors have a great influence on the fabrication of accurate photonic crystal, especially porous silicon-based photonic crystals. Compared with the binary photonic crystal, polybasic structure photonic crystal shows more stability and smaller effect of the random fluctuation. In this paper, we have fabricated a novel simple porous silicon polybasic Bragg's mirror combined with excellent specific antigen–antibody inmunoreaction as an immunosensor for determining Hydroxysafflor yellow A (HSYA), which is the main chemical component of Carthamus tinctorius L. The binding of HSYA and the polyclonal anti-HSYA antibodies causes red shifts in the reflection spectrum of the sensor, and the red shift was proportional to the HSYA concentration with linear relationship ranging from 1 to 3μgmL⁻¹ with a detection limit of 0.78ngmL⁻¹. Importantly, this research offers hope for development of a commercial porous silicon-based immunosensor for component determination of C. tinctorius L. or other antigens.

Keywords: Porous silicon; Immunosensor; Polybasic structure; Hydroxysafflor yellow A

Adjustable wettability of paperboard by liquid flame spray nanoparticle deposition by Milena Stepien; Jarkko J. Saarinen; Hannu Teisala; Mikko Tuominen; Mikko Aromaa; Jurkka Kuusipalo; Jyrki M. Mäkelä; Martti Toivakka (pp. 1911-1917).

Liquid flame spray process (LFS) was used for depositing TiO_x and SiO_x nanoparticles on paperboard to control wetting properties of the surface. By the LFS process it is possible to create either superhydrophobic or superhydrophilic surfaces. Changes in the wettability are related to structural properties of the surface, which were characterized using scanning electron microscope (SEM) and atomic force microscope (AFM). The surface properties can be ascribed as a correlation between wetting properties of the paperboard and the surface texture created by nanoparticles. Surfaces can be produced inline in a one step roll-to-roll process without need for additional modifications. Furthermore, functional surfaces with adjustable hydrophilicity or hydrophobicity can be fabricated simply by choosing appropriate liquid precursors.

Keywords: Liquid flame spray process; Nanocoatings; Wettability; Paperboard

Annealing effect on planar waveguides in LiNbO₃ produced by oxygen ion implantation by Xiu-Hong Liu; Qing Huang; Jin-Hua Zhao; Peng Liu; Xue-Lin Wang; Ji-Fu Du; Ning-Kang Huang (pp. 1918-1922).

We reported on planar waveguides in stoichiometric lithium niobate fabricated by 4.5MeV oxygen ion implantation with a dose of 6×10¹⁴ions/cm² at room temperature. After ion implantation, these samples were annealed at 240°C, 260°C, and 300°C for 30min. We investigated annealing effect on the guiding modes and near-field images in the waveguides by prism-coupling method and end-face coupling method respectively. We found that for the extraordinary refractive index a positive alternation occurred in the near-surface region while a negative alternation happened at the end of ion track. Moreover, we measured the transmission spectra for the pure sample and implanted samples before and after annealed at different temperatures, and we observed an absorption peak at ∼480nm (2.6eV) in all of these SLN samples.

Keywords: Key words; Waveguides; Ion implantation; Lithium niobate; Annealing

Annealing effect on planar waveguides in LiNbO₃ produced by oxygen ion implantation by Xiu-Hong Liu; Qing Huang; Jin-Hua Zhao; Peng Liu; Xue-Lin Wang; Ji-Fu Du; Ning-Kang Huang (pp. 1918-1922).

Keywords: Key words; Waveguides; Ion implantation; Lithium niobate; Annealing

Effect of annealing on the surface and band gap alignment of CdZnS thin films by T. Prem Kumar; S. Saravanakumar; K. Sankaranarayanan (pp. 1923-1927).

Effects of the annealing temperature on structural, optical and surface properties of chemically deposited cadmium zinc sulfide (CdZnS) films were investigated. X-ray diffraction (XRD) results showed that the grown CdZnS thin films formed were polycrystalline with hexagonal structure. Atomic force microscopy (AFM) studies showed that the surface roughness of the CdZnS thin films was about 60–400nm. Grain sizes of the CdZnS thin films varied between 70 and 300nm as a function of annealing temperature. The root mean square surface roughness of the selected area, particular point, average roughness profile, topographical area of roughness were measured using the reported AFM software. The band gaps of CdZnS thin films were determined from absorbance measurements in the visible range as 300nm and 1100nm, respectively, using Tauc theory.

Keywords: CdZnS thin films; X-ray diffraction; Atomic force microscopy; Band gap; Surface properties

Effect of annealing on the surface and band gap alignment of CdZnS thin films by T. Prem Kumar; S. Saravanakumar; K. Sankaranarayanan (pp. 1923-1927).

Keywords: CdZnS thin films; X-ray diffraction; Atomic force microscopy; Band gap; Surface properties

Template-free synthesis of TS-1 zeolite film on tubular mullite support by Lie Meng; Hong Jiang; Rizhi Chen; Xuehong Gu; Wanqin Jin (pp. 1928-1931).

The TS-1 film on tubular mullite support was prepared by secondary growth via template-free route using tetraethyl orthosilicate (TEOS) and tetrabutyl orthotitanate (TBOT) as silica and titanium sources. The as-made films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and ultraviolet–visible spectroscopy (UV–vis). Continuous TS-1 seed layer was bonded tightly to the mullite substrates. After secondary growth in the template-free synthesis solution, intergrown TS-1 zeolite film with the typical MFI-type structure was formed on the outer surface of support. The Si atoms in zeolitic lattice were found to be isomorphously substituted by Ti atoms which existed only in tetrahedral coordination. The thickness of the obtained TS-1 zeolite film was less than 20μm.

Keywords: TS-1 zeolite film; Template-free; Mullite tube; Secondary growth

Template-free synthesis of TS-1 zeolite film on tubular mullite support by Lie Meng; Hong Jiang; Rizhi Chen; Xuehong Gu; Wanqin Jin (pp. 1928-1931).

Keywords: TS-1 zeolite film; Template-free; Mullite tube; Secondary growth

Possibilities of LA-ICP-MS technique for the spatial elemental analysis of the recent fish scales: Line scan vs. depth profiling by Markéta Holá; Jiří Kalvoda; Hana Nováková; Radek Škoda; Viktor Kanický (pp. 1932-1940).

LA-ICP-MS and solution based ICP-MS in combination with electron microprobe are presented as a method for the determination of the elemental spatial distribution in fish scales which represent an example of a heterogeneous layered bone structure.Two different LA-ICP-MS techniques were tested on recent common carp ( Cyprinus carpio) scales:(a)A line scan through the whole fish scale perpendicular to the growth rings. The ablation crater of 55μm width and 50μm depth allowed analysis of the elemental distribution in the external layer. Suitable ablation conditions providing a deeper ablation crater gave average values from the external HAP layer and the collagen basal plate.(b)Depth profiling using spot analysis was tested in fish scales for the first time. Spot analysis allows information to be obtained about the depth profile of the elements at the selected position on the sample.The combination of all mentioned laser ablation techniques provides complete information about the elemental distribution in the fish scale samples. The results were compared with the solution based ICP-MS and EMP analyses. The fact that the results of depth profiling are in a good agreement both with EMP and PIXE results and, with the assumed ways of incorporation of the studied elements in the HAP structure, suggests a very good potential for this method.

Keywords: Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS); Fish scale; Hydroxyapatite layer; Metal; Spatial distribution

Behavior of multi-walled carbon nanotubes on the porosity and microstructure of cement-based materials by Thanongsak Nochaiya; Arnon Chaipanich (pp. 1941-1945).

The porosity and microstructure of a Portland cement–multi-walled carbon nanotube composite were investigated. Multi-walled carbon nanotubes (CNTs), up to 1wt.% of cement, synthesized by infusion chemical vapor deposition, and Portland cement type I (PC) were used to produce pastes with a water to cement ratio of 0.5. Mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM) were used to characterize Portland cement–CNTs systems. MIP analysis of the results indicates that total porosity of the mixes with CNTs was found to decrease with increasing CNTs content. Moreover, an important effect of additional CNTs was a reduction in the number of mesopores, while SEM technique showed dispersion of CNTs between the hydration phases of Portland cement pastes.

Keywords: Cement; Carbon nanotubes; Nano additives; Microstructure; Mercury intrusion porosimetry

Behavior of multi-walled carbon nanotubes on the porosity and microstructure of cement-based materials by Thanongsak Nochaiya; Arnon Chaipanich (pp. 1941-1945).

Keywords: Cement; Carbon nanotubes; Nano additives; Microstructure; Mercury intrusion porosimetry

A comparative study of field-emission from different one dimensional carbon nanostructures synthesized via thermal CVD system by A. Jha; D. Banerjee; K.K. Chattopadhyay (pp. 1946-1951).

Different one dimensional (1D) carbon nanostructures, such as carbon nanonoodles (CNNs), carbon nanospikes (CNSs) and carbon nanotubes (CNTs) have been synthesized via thermal chemical vapour deposition (TCVD) technique. The different 1D morphologies were synthesized by varying the substrate material and the deposition conditions. The as-prepared samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). FESEM and TEM images showed that the diameters of the CNNs and CNTs were ∼40nm while the diameters of the CNSs were around 100nm. Field emission studies of the as-prepared samples showed that CNSs to be a better field emitter than CNNs, whereas CNTs are the best among the three producing large emission current. The variation of field emission properties with inter-electrode distance has been studied in detail. Also the time dependent field emission studies of all the nanostructures have been carried out.

Keywords: PACS; 61.48.De; 81.15.Gh; 79.70.+qCarbon nanostructure; Chemical vapor deposition; Field emission

A comparative study of field-emission from different one dimensional carbon nanostructures synthesized via thermal CVD system by A. Jha; D. Banerjee; K.K. Chattopadhyay (pp. 1946-1951).

Keywords: PACS; 61.48.De; 81.15.Gh; 79.70.+qCarbon nanostructure; Chemical vapor deposition; Field emission

Interfacial morphology and friction properties of thin PEO and PEO/PAA blend films by Xianke Gu; Guojian Wang (pp. 1952-1959).

The scanning force microscope (SFM) was used to investigate morphology of poly(ethylene oxide) (PEO) and poly(acrylic acid) (PAA) blend. The effect of solvent and dewetting in surface structure of PEO film was reported. The results manifested that the crystallization of PEO could be suppressed completely in ultrathin region via using chloroform as a solvent, and the branched-like crystallization was recovered after dewetting. Also, the effect of thickness, the ratio of PEO/PAA and dewetting in surface morphology of PEO–PAA blend films were investigated. These results showed that the crystallization was highly dependent on the ratio of PEO/PAA and the thickness of blend film. Furthermore, we assembled the PEO/PAA layer-by-layer film by spin-casting method for the first time, which exhibited highly efficiency. As a complementary tool, we also used lateral force microscopy (LFM) to explore surface information of these films. The result was indicative of interfacial constraints in ultrathin region, and also was supported by the results showing the spin-casting PEO/PAA blends rather than heterogeneous mixture.

Keywords: Scanning force microscopy (SFM); Lateral force microscopy (LFM); Morphology; PEO; PEO/PAA layer-by-layer film; Spin-casting; Crystallization

Interfacial morphology and friction properties of thin PEO and PEO/PAA blend films by Xianke Gu; Guojian Wang (pp. 1952-1959).

Keywords: Scanning force microscopy (SFM); Lateral force microscopy (LFM); Morphology; PEO; PEO/PAA layer-by-layer film; Spin-casting; Crystallization

Nanonails structured ferric oxide thick film as room temperature liquefied petroleum gas (LPG) sensor by B.C. Yadav; Satyendra Singh; Anuradha Yadav (pp. 1960-1966).

In the present work, ferric oxide nanonails were prepared by screen printing method on borosilicate glass substrate and their electrical and LPG sensing properties were investigated. The structural and morphological characterizations of the material were analyzed by means of X-ray diffraction (XRD) and Scanning electron microscopy (SEM). XRD pattern revealed crystalline α-phase and rhombohedral crystal structure. SEM images show nanonails type of morphology throughout the surface. Optical characterization of the film was carried out by UV–visible spectrophotometer. By Tauc plot the estimated value of band gap of film was found 3.85eV. The LPG sensing properties of the ferric oxide film were investigated at room temperature for different vol.% of LPG. The variations in electrical resistance of the film were measured with the exposure of LPG as a function of time. The maximum values of sensitivity and sensor response factors were found 51 and 50 respectively for 2vol.% of LPG. The activation energy calculated from Arrhenius plot was found 0.95eV. The response and recovery time of sensing film were found ∼120s and 150s respectively. These experimental results show that nanonails structured ferric oxide is a promising material as LPG sensor.

Keywords: Thick film sensors; Arrhenius plot; Tauc plot; Sensitivity; Surface morphology

Nanonails structured ferric oxide thick film as room temperature liquefied petroleum gas (LPG) sensor by B.C. Yadav; Satyendra Singh; Anuradha Yadav (pp. 1960-1966).

Keywords: Thick film sensors; Arrhenius plot; Tauc plot; Sensitivity; Surface morphology

Synthesis and performance of Y-doped La_0.7Sr_0.3CrO3−_δ as a potential anode material for solid oxygen fuel cells by Xiufang Zhu; Qin Zhong; Xuejun Zhao; Han Yan (pp. 1967-1971).

Y-doped La_0.7Sr_0.3CrO3−_δ is a promising anode catalyst for solid oxygen fuel cell (SOFC). The performances of chemical and physical are measured by SEM, XRD and FT-IR. The conductivities of catalyst are measured by DC four-probe method in 20% H₂S–N₂, 3% H₂–N₂ and air from 573K to 1173K, respectively. The results show that Y-doped La_0.7Sr_0.3CrO3−_δ powders have perfect perovskite phase structure with no extra peaks and exhibit good chemical compatibility with Ce_0.8Sm_0.2O_1.9 (as electrolyte) in air. Through XRD and FT-IR analysis no sulfur-containing species is detected after exposure to the 20% H₂S at 1173K for 5h. Meanwhile, Y-doped La_0.7Sr_0.3CrO3−_δ shows that the highest conductivity is 0.21S/cm at 1173K in H₂S. The open circuit voltages are 0.85V at 1173K in H₂S and 1.04V at 823K in H₂. The maximal power densities are 12.4mW/cm² in H₂S and 1.59W/cm² in H₂ for cells comprising Y-doped La_0.7Sr_0.3CrO3−_δ–Sm_0.2Ce_0.8O_1.9/Sm_0.2Ce_0.8O_1.9/Ag.

Keywords: SOFC; Hydrogen sulfide; Anode catalyst

Synthesis and performance of Y-doped La_0.7Sr_0.3CrO3−_δ as a potential anode material for solid oxygen fuel cells by Xiufang Zhu; Qin Zhong; Xuejun Zhao; Han Yan (pp. 1967-1971).

Keywords: SOFC; Hydrogen sulfide; Anode catalyst

Flowerlike PtCl₄/Bi₂WO₆ composite photocatalyst with enhanced visible-light-induced photocatalytic activity by Fang Duan; Yan Zheng; MingQing Chen (pp. 1972-1978).

Flowerlike PtCl₄/Bi₂WO₆ composite photocatalyst was successfully synthesized through a simple two-step method involving a template-free hydrothermal process and the following impregnation treatment. The samples were fully characterized by the study of X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), and UV–Vis absorption spectra. The results indicated that the doping of Pt species did not affect the crystal structure and the morphology of Bi₂WO₆ photocatalyst, but it had great influences on the photocatalytic activity of Bi₂WO₆ towards rhodamine-B (RhB) degradation. Besides, the Pt species was found to be present as PtCl₄ in the composite samples, and also an optimal Pt species content on the surface of Bi₂WO₆ photocatalyst was discovered with the highest photocatalytic ability. The improved photocatalytic performance could be ascribed to the enhanced interfacial charge transfer and the inhibited recombination of electron–hole pairs. Meanwhile, a possible mechanism for RhB photocatalytic degradation over PtCl₄/Bi₂WO₆ catalyst was also proposed.

Keywords: PtCl; ₄; /Bi; ₂; WO; ₆; Chemical synthesis; Photocatalytic activity

Flowerlike PtCl₄/Bi₂WO₆ composite photocatalyst with enhanced visible-light-induced photocatalytic activity by Fang Duan; Yan Zheng; MingQing Chen (pp. 1972-1978).

Keywords: PtCl; ₄; /Bi; ₂; WO; ₆; Chemical synthesis; Photocatalytic activity

Nitrogen doping in pulsed laser deposited ZnO thin films using dense plasma focus by S. Karamat; R.S. Rawat; T.L. Tan; P. Lee; S.V. Springham; E. Ghareshabani; R. Chen; H.D. Sun (pp. 1979-1985).

Pulsed laser deposition synthesized ZnO thin films, grown at 400°C substrate temperature in different oxygen gas pressures, were irradiated with 6 shots of pulsed nitrogen ions obtained from 2.94kJ dense plasma focus to achieve the nitrogen doping in ZnO. Structural, compositional and optical properties of as-deposited and nitrogen ion irradiated ZnO thin films were investigated to confirm the successful doping of nitrogen in irradiated samples. Spectral changes have been seen in the nitrogen irradiated ZnO thin film samples from the low temperature PL measurements. Free electron to acceptor emissions can be observed from the irradiated samples, which hints towards the successful nitrogen doping in films. Compositional analysis by X-ray photoelectron spectroscopy and corresponding shifts in binding energy core peaks of oxygen and nitrogen confirmed the successful use of plasma focus device as a novel source for nitrogen ion doping in ZnO thin films.

Keywords: Dense plasma focus; Amorphization; Nitrogen doping

Nitrogen doping in pulsed laser deposited ZnO thin films using dense plasma focus by S. Karamat; R.S. Rawat; T.L. Tan; P. Lee; S.V. Springham; E. Ghareshabani; R. Chen; H.D. Sun (pp. 1979-1985).

Keywords: Dense plasma focus; Amorphization; Nitrogen doping

Observation of regular defects formed on the surface of PbTe thin films grown by molecular beam epitaxy by Bingpo Zhang; Chunfeng Cai; Lian Hu; Xiaodong Wei; Huizhen Wu (pp. 1986-1989).

Regular shape defects on the surface of PbTe thin films grown by molecular beam epitaxy (MBE) were studied by scanning electron microscope (SEM). Two types of regular shape defects were observed on Te-rich PbTe films grown at substrate temperature T≥235°C with a beam flux ratio of Te to PbTe ( R_f) to be 0.5 and at 280°C with a R_f≥0.4, which include cuboids and triangular pyramids. The formation mechanism of the observed regular shape defects is interpreted as following: They are the outcome of fast growth rate along {100} crystal planes that have the lowest surface energy and the enclosure of the {100} crystal planes. The formation of the regular shape defects in the growth of PbTe needs appropriate substrate temperature and Te-rich ambience. However, when R_f is decreased low enough to make the films slightly Pb-rich, triangular pits that originate from the insufficient glide of the threading dislocations along the main 〈110〉 {100} glide system of PbTe in Cottrell atmosphere, will be the main feature on the film surface.

Keywords: Lead telluride thin films; Regular shape defects; Scanning electron microscope

Observation of regular defects formed on the surface of PbTe thin films grown by molecular beam epitaxy by Bingpo Zhang; Chunfeng Cai; Lian Hu; Xiaodong Wei; Huizhen Wu (pp. 1986-1989).

Keywords: Lead telluride thin films; Regular shape defects; Scanning electron microscope

A magnetron sputtering technique to prepare a-C:H films: Effect of substrate bias by Yongxia Wang; Yinping Ye; Hongxuan Li; Li Ji; Jianmin Chen; Huidi Zhou (pp. 1990-1995).

Amorphous hydrogenated carbon (a-C:H) films were deposited by magnetron sputtering with a mixture gas of Ar and CH₄. The a-C:H films deposited by this method have relatively low internal stress (<1GPa) compared to some films deposited by conventional deposition process. The effects of substrate bias voltage on microstructure, surface morphology and mechanical properties of the films were investigated by various techniques. It has been found that the polymer-like structure is dominated at low bias voltage (−100V), while the diamond-like structure with the highest hardness and internal stress is the main feature of the a-C:H films deposited under high bias voltage (−300V). With increasing the bias voltage further, the feature of diamond-like structure decreases associating with the increase of graphitization. The frictional test shows that the friction coefficient and wear rate of the a-C:H films are depended strongly on structure and mechanical properties, which were ultimately influenced by the deposition method and bias voltage.

Keywords: a-C:H film; Magnetron sputtering; Substrate bias; Microstructure; Tribological property

A magnetron sputtering technique to prepare a-C:H films: Effect of substrate bias by Yongxia Wang; Yinping Ye; Hongxuan Li; Li Ji; Jianmin Chen; Huidi Zhou (pp. 1990-1995).

Keywords: a-C:H film; Magnetron sputtering; Substrate bias; Microstructure; Tribological property

Influence of thermal annealing duration of buffer layer on the crystalline quality of In_0.82Ga_0.18As grown on InP substrate by LP-MOCVD by Xia Liu; Hang Song; Guoqing Miao; Hong Jiang; Lianzhen Cao; Dabing Li; Xiaojuan Sun; Yiren Chen (pp. 1996-1999).

In_0.82Ga_0.18As epilayers were grown on InP substrates using a two-step growth technique by LP-MOCVD. A homogeneous low-temperature (450°C) In_0.82Ga_0.18As buffer layer was introduced to improve the crystalline quality of epilayers. The influence of low-temperature buffer layer deposition condition, such as thermal annealing duration, on the crystalline quality of the In_0.82Ga_0.18As epilayer was investigated. Double-crystal X-ray diffraction measurement, Hall measurement, and Raman scattering spectrum were used to evaluate the In_0.82Ga_0.18As epilayers. Atomic force microscope was used to study the surface morphology. It is found that the In_0.82Ga_0.18As epilayer, with buffer layer thermal annealing for 5min, exhibits the best crystalline quality. The change of the surface morphology of the buffer layer after thermal annealing treatment was suggested to explain the phenomenon.

Keywords: In; _0.82; Ga; _0.18; As; MOCVD; Buffer layer annealing duration; Crystalline quality

Iron sulphide formation in the ferric stearate Langmuir–Blodgett films by S. Kundu; A.K.M. Maidul Islam; M. Mukherjee (pp. 2000-2003).

Ferric stearate (FeSt) Langmuir–Blodgett (LB) films have been reacted chemically with H₂S gas for making iron sulphide within the organic matrix. Films, before and after the reaction with H₂S, have been analyzed with the X-ray reflectivity (XRR), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) studies. After sulphidation, more ‘pinhole’ defects form which changes the film morphology and the number of layers increases due to the rearrangement of the molecules. Formation of less ordered iron sulphide within the stearic acid multilayers after sulphidation increases the interfacial roughness that decreases the reflectivity. XPS analysis shows that polysulphide forms within the microenvironment of the FeSt LB films after reaction with H₂S whereas both mono and polysulphide are produced when the reaction occurs with FeSt in bulk.

Keywords: LB film; Ferric stearate; Iron sulphide; XPS; X-ray reflectivity; AFM

Iron sulphide formation in the ferric stearate Langmuir–Blodgett films by S. Kundu; A.K.M. Maidul Islam; M. Mukherjee (pp. 2000-2003).

Keywords: LB film; Ferric stearate; Iron sulphide; XPS; X-ray reflectivity; AFM

Simulation of the growth kinetics of the (FeB/Fe₂B) bilayer obtained on a borided stainless steel by M. Keddam (pp. 2004-2010).

The present work is an attempt to simulate the growth kinetics of the (FeB/Fe₂B) bilayer grown on a substrate made of AISI 316 stainless steel by the application of the powder-pack boriding process, and using four different temperatures (1123, 1173, 1223 and 1273K) and five exposure times (2, 4, 6, 8 and 10h). The adopted diffusion model solves the mass balance equation at each growth front: (FeB/Fe₂B or FeB/substrate) under certain assumptions and without considering the diffusion zone. To consider the effect of the incubation times for the borides formation, the temperature-dependent function ϕ( T) was incorporated in the model. To validate this model, a computer code written in Matlab (version 6.5), was developed with the purpose of simulating the kinetics of the boride layers. This computer code uses the following parameters as input data: (the boriding temperature, the treatment time, the upper and lower limits of boron concentration in each iron boride, the diffusion coefficients of boron in the FeB and Fe₂B phases as well as the ϕ( T) parameter). The outputs of the computer code are the parabolic growth constant at each growth front and the thicknesses of the FeB and Fe₂B layers. A good agreement was obtained between the experimental parabolic growth constants taken from a reference work [I. Campos-Silva et al., Formation and kinetics of FeB/Fe₂B layers and diffusion zone at the surface of AISI 316 borided steels, Surf. Coat Technol., 205 (2010) 403–412] and the simulated values of the parabolic growth constants ( k_FeB and k₁). The present model was also able to predict the thicknesses of the FeB and Fe₂B layers at a temperature of 1243K during 3 and 5h.In addition, the mass gain at the material surface was also estimated as a function of the time and the upper boron content in each iron boride phase. It was shown that the simulated values of the generated mass gain are very sensitive to the increase of both temperature and the upper boron contents in the FeB and Fe₂B phases.

Keywords: Powder-pack boriding; Boride layers; Growth kinetics; Incubation time; Parabolic growth constant

Simulation of the growth kinetics of the (FeB/Fe₂B) bilayer obtained on a borided stainless steel by M. Keddam (pp. 2004-2010).

Keywords: Powder-pack boriding; Boride layers; Growth kinetics; Incubation time; Parabolic growth constant

PM-IRRAS studies of the adsorption and stability of organophosphonate monolayers on passivated NiTi surfaces by M. Maxisch; C. Ebbert; B. Torun; N. Fink; T. de los Arcos; J. Lackmann; H.J. Maier; G. Grundmeier (pp. 2011-2018).

Alkylphosphonic acids of different alkyl chain lengths were adsorbed on electrochemically polished NiTi surfaces from ethanolic solutions. The electropolishing process led to passive films mainly composed of Ti-oxyhydroxide. The surface showed nanoscopic etching pits with a depths of about 2nm and a diameter of about 20nm. The interfacial binding mechanism of the phosphonic acid group to the oxyhydroxide surface and the ordering of the monolayer were spectroscopically analysed by means of infrared reflection absorption FTIR-spectroscopy with (PM-IRRAS) and without (IRRAS) photoelastic modulation. The comparison of IRRAS and PM-IRRAS data of the long chain octadecylphosphonic acid monolayer proved that the binding mechanism of the phosphonic acid group to the oxyhydroxide surface is based on a mono- or bidentate bond, which is not stable in the presence of high water activities. An alkyl chain length of 17 CH₂ groups is required for the formation of self-assembled monolayers, which are stable in aqueous environments. These long chain aliphatic organophosphonic acid monolayers were shown to inhibit anodic and cathodic surface reactions.

Keywords: PM-IRRAS; Organophosphonic acid; Self-assembled monolayer; NiTi alloy

Dependence of Cm on the composition of solid binary propellants in ablative laser propulsion by Carlos A. Rinaldi; Norberto G. Boggio; Daniel Rodriguez; Alberto Lamagna; Alfredo Boselli; Francisco Manzano; Jorge Codnia; M. Laura Azcárate (pp. 2019-2023).

Propulsion pellets of different metal/salt (Zn/CaCO₃) composition have been prepared. The impulse imparted to the pellet by the laser has been measured using two different methods: a torsion pendulum and a piezoelectric sensor. The dependence of the coupling coefficient, C_m, on the composition of the solid binary propellants in ablative laser propulsion has been investigated under different experimental conditions: in vacuum and at atmospheric pressure as well as with two different wavelengths, IR and UV. The composition of the Zn/CaCO₃ propellant mixture that optimizes the coupling coefficient, C_m, has been determined.

Keywords: Laser propulsion; Propellant; Laser ablation; Coupling coefficient

Characterization of vanadium-doped mesoporous titania and its adsorption of gaseous benzene by Thuy-Duong Nguyen-Phan; Myoung Bock Song; Hyunran Yun; Eui Jung Kim; Eun-Suok Oh; Eun Woo Shin (pp. 2024-2031).

A series of vanadium-doped mesoporous titania with different metal contents was synthesized in the study via a sol–gel process with the assistance of a dodecylamine surfactant. The existence of vanadium ions not only suppressed crystallization and sintering but also enhanced the porosity of the mesoporous TiO₂. Varying the vanadium concentration led to significant changes in the chemical oxidation state of each component. The presence of metal dopants significantly improved the removal efficiency of benzene and the doping the titania with 5mol% vanadium removed the most benzene, regardless of the adsorption temperature. The adsorption behavior was elucidated by the specific surface area, the interactions between surface hydroxyl groups and the π-electrons of benzene, and the formation of σ-bonding and d-π* back-donation between the adsorbent and organic compounds.

Keywords: Vanadium; Mesoporous titania; Benzene; Adsorption

The role of surface terminations on the band structure and optical properties of silicon nanonets by L.H. Lin; D.X. Li; J.Y. Feng; Y. Wang (pp. 2032-2037).

The ab initio calculations are carried out to investigate the effect of hydrogen, oxygen and nitrogen terminations on the properties of the band edge and the values of the band-gap, as well as the oscillator strength of the silicon nanonets (SiNNs). The oxygen functional groups are found to effectively preserve the direct band-gap nature of the SiNNs, and even change the luminescence properties of the silicon nanowires (SiNWs) to the direct band-gap transition. The appreciable oscillator strength of the first direct transition is obtained for the oxygen terminated nanostructure. The study on the electronic states indicates that the variation of the band edge caused by the surface terminations is attributed to the change of the state compositions. These surface modifications are thought to be useful for silicon band-gap engineering in the area of optoelectronics.

Keywords: Silicon nanonets; Surface terminations; Band structure; Momentum matrix element; Density of states

The role of surface terminations on the band structure and optical properties of silicon nanonets by L.H. Lin; D.X. Li; J.Y. Feng; Y. Wang (pp. 2032-2037).

Keywords: Silicon nanonets; Surface terminations; Band structure; Momentum matrix element; Density of states

Interaction of copper with sulfur on the sulfur-terminated Si(111)-(7×7) surface by Yong Ping Zhang; Kian Soon Yong; Guo Qin Xu; Xing Yu Gao; Xue-Sen Wang; Andrew Thye Shen Wee (pp. 2038-2041).

The adsorption of S₂ on the Si(111)-(7×7) surface and the interaction of copper and sulfur on this sulfur-terminated Si(111) surface have been studied using synchrotron irradiation photoemission spectroscopy and scanning tunneling microscopy. The adsorption of S₂ at room temperature results in the passivation of silicon dangling bonds of Si(111)-(7×7) surface. Excessive sulfur forms S_n species on the surface. Copper atoms deposited at room temperature directly interact with S-adatoms through the formations of Cu–S bonds. Upon annealing the sample at 300°C, CuS_x nanocrystals were produced on the sulfur-terminated Si(111) surface.

Keywords: Silicon; Sulfur; Copper; Photoemission spectroscopy; Scanning tunneling microscopy; Nanostructures

Interaction of copper with sulfur on the sulfur-terminated Si(111)-(7×7) surface by Yong Ping Zhang; Kian Soon Yong; Guo Qin Xu; Xing Yu Gao; Xue-Sen Wang; Andrew Thye Shen Wee (pp. 2038-2041).

Keywords: Silicon; Sulfur; Copper; Photoemission spectroscopy; Scanning tunneling microscopy; Nanostructures

Effects of the Hf content on the microstructure and magnetic properties of Co–Hf–Ta thin films by Shu-Wen Huang; Yuan-Tai Lai; Jenq-Gong Duh (pp. 2042-2045).

Effects of the Hf content in Co–Hf–Ta thin films on the microstructure and magnetic properties were investigated in this study. It was found that appropriate Hf addition can effectively refine the Co grain size. Co grain sizes sharply decreased from 50nm down to 2.3nm with increasing the Hf content from 1.02at.% to 2.81at.%, leading to the reduced magneto-crystalline anisotropy. The Co–Hf–Ta thin films with small Co grains reveal low anisotropy field, low coercivity, and high resistivity. By optimizing the Hf content, the film with Hf concentration of 2.81at.% exhibits excellent soft magnetic properties: high saturation magnetization (4 πM_S∼13.6kG), and low coercivity ( H_C∼0.6Oe). The effective permeability of the film reaches 800 and remains constant up to 1GHz.

Keywords: Magnetic thin films; Magneto-crystalline anisotropy; Co–Hf–Ta; Permeability

Effects of the Hf content on the microstructure and magnetic properties of Co–Hf–Ta thin films by Shu-Wen Huang; Yuan-Tai Lai; Jenq-Gong Duh (pp. 2042-2045).

Keywords: Magnetic thin films; Magneto-crystalline anisotropy; Co–Hf–Ta; Permeability

Efficient fabrication of substrates for surface-assisted laser desorption/ionization mass spectrometry using laser ablation in liquids by Takeshi Tsuji; Takeshi Mizuki; Masato Yasutomo; Masaharu Tsuji; Hideya Kawasaki; Tetsu Yonezawa; Fumitaka Mafuné (pp. 2046-2050).

Substrates for the surface-assisted laser desorption ionization (SALDI) technique were prepared using electrophoresis of gold nanoparticles produced by laser ablation in liquids. Throughout the preparation, no supplemental reagent was added for the stabilization and deposition of nanoparticles. Nanoparticles were deposited more uniformly using the electrophoresis technique than using dropping of the solution. Results demonstrated that the higher uniformity of the deposition of nanoparticles improved the reproducibility of SALDI measurements. Furthermore, the thickness of the deposited nanoparticles influences the SALDI efficiency.

Keywords: Laser ablation; Nanoparticles; Colloids; Electrophoresis; Surface-assisted laser desorption/ionization; SALDI; Mass spectrometry

Bioactive calcium phosphate coating formed on micro-arc oxidized magnesium by chemical deposition by G.Y. Liu; J. Hu; Z.K. Ding; C. Wang (pp. 2051-2057).

In order to improve the bioactivity of the micro-arc oxidized magnesium, a calcium phosphate coating was formed on the surface of micro-arc oxidized magnesium using a chemical method. The microstructures of the substrate and the calcium phosphate coating before and after the simulated body fluids (SBF) incubation were characterized by X-ray diffraction, Fourier-transformed infrared spectroscopy and scanning electron microscopy. The results showed that the calcified coating was composed of calcium deficient hydroxyapatite (HA) and dicalcium phosphate dihydrate (DCPD). After SBF incubation, some new apatite formation on the calcified coating surface from SBF could be found. The corrosion behaviours of the samples in SBF were also investigated by potentiodynamic polarization curves and immersion tests. The results showed that calcium phosphate coating increased the corrosion potential, and decreased the hydrogen gas release.

Keywords: Bioactive material; Magnesium; Micro-arc oxidization; Calcium phosphate; Corrosion

Bioactive calcium phosphate coating formed on micro-arc oxidized magnesium by chemical deposition by G.Y. Liu; J. Hu; Z.K. Ding; C. Wang (pp. 2051-2057).

Keywords: Bioactive material; Magnesium; Micro-arc oxidization; Calcium phosphate; Corrosion

Influence of filler type on wet skid resistance of SSBR/BR composites: Effects from roughness and micro-hardness of rubber surface by Yuan-Xia Wang; You-Ping Wu; Wen-Ji Li; Li-Qun Zhang (pp. 2058-2065).

The wet skid resistance (WSR) of SSBR/BR(solution styrene–butadiene rubber/butadiene rubber) composites filled with carbon black, silica, and nano-diamond partly replacing carbon black or silica, respectively, was measured with a portable British Pendulum Skid Tester (BPST). A dynamic mechanical thermal analyzer was used to obtain the viscoelasticity of the composites. A 3D scanning white-light interfering profilometer was used and the scratch test performed to characterize surface roughness and micro-roughness, respectively, of the composites. WSR of the silica-filled composite was better than that of the carbon black-filled one, and further enhancement of WSR was obtained by replacing silica with nano-diamond. Tan δ of the composites at 0°C, 10Hz, and tensile strain of 2% did not show good correlation with WSR. The surface roughness of the composites had effects on WSR. The scratch test indicated that the higher the hardness of the filler in the composite, the higher the micro-hardness and the better the WSR. Therefore, the surface micro-hardness of the composites is an important factor affecting WSR, besides viscoelasticity and surface roughness.

Keywords: Wet skid resistance; Strain amplitude; Nano-diamond; Surface analysis; Scratch test

Morphology and distribution of subsurface damage in optical fused silica parts: Bound-abrasive grinding by Yaguo Li; Nan Zheng; Haibo Li; Jing Hou; Xiangyang Lei; Xianhua Chen; Zhigang Yuan; Zhaozhou Guo; Jian Wang; Yinbiao Guo; Qiao Xu (pp. 2066-2073).

The depth and morphology of subsurface damage (SSD) in fused silica samples ground with diamond grinding wheels were investigated. The factors possibly influencing the SSD depth of ground samples were examined. The results demonstrate that the SSD depth is most responsive to diamond grit size while the processing parameters (i.e. depth of cut, feed rate, and wheel peripheral speed) have marginal effects on the SSD depth. The SSD depth decreases with the abrasive/grit size of diamond wheels and slightly diminishes with the decrease of cutting depth but little influenced by feeding rate and wheel speed. The morphology inspection shows that the density of subsurface cracks in ground fused silica samples decays exponentially with the depth from the ground surface into the bulk and the cracks vanish at a certain depth that depends on the mechanical and physical properties of samples and diamond abrasives/grits.

Keywords: Fused silica; Diamond grinding; Subsurface damage; Depth of cut; Wheel peripheral speed; Feeding rate

Effect of temperature of annealing on optical, structural and electrochromic properties of sol–gel dip coated molybdenum oxide films by M. Dhanasankar; K.K. Purushothaman; G. Muralidharan (pp. 2074-2079).

The sol–gel dip-coating method is used for the preparation of MoO₃ thin films. The 6 layered MoO₃ films were prepared and annealed at various temperatures in the range of 200–350°C. The band gap value for MoO₃ films were calculated from optical absorption measurements and it is in the range of 3.55–3.73eV. XRD spectrum reveals (020) is the major diffraction plane for the films prepared above 250°C, which reveals the formation of MoO₃ in α-orthorhombic phase. The films prepared at 200°C and 250°C exhibits amorphous nature. The FTIR spectrum confirms the presence of Mo–O–Mo and MoO bonds. Nanorods were observed in the SEM images in the case of MoO₃ films prepared above 250°C. The films prepared at 250°C exhibit maximum anodic diffusion coefficient of 9.61×10⁻¹¹cm²/s. The same film exhibits the change in optical transmission of 58.4% at 630nm with the optical density of 0.80.

Keywords: Electrochromism; MoO; ₃; Thin films; Sol–gel dip coating

Morphological control of polymerized n-octadecylsiloxane by Qiuping Lu; Tiange Hao; Qingping Ke; Wanjun Wang; Tao He; Xue-Mei Li (pp. 2080-2085).

Polymerized n-octadecylsiloxane (PODS) was prepared by coating glass substrates with liquid ocatdecyltrichlorosilane (OTS) followed by dipping-in a solvent. The morphology control of PODS was investigated by the post curing temperature as well as the use of different solvents. The resulting substrates were characterized by scanning electron microscopy (SEM), contact angle measurements, and wide angle X-ray diffractometry (XRD). It is shown that both post curing temperature and extracting solvents affect the morphology of PODS. The temperature dependent morphology was investigated and is ascribed to the physiochemical properties of PODS. For the solvent-dependent morphology, it is proposed that the solvation capability of a solvent to OTS and the presence of a hydrophilic/hydrophobic interface are critical in the PODS morphology. This paper shows the controlling parameter and possible explanation in the crystallinity and wettability of PODS films, which may be useful to other silane-based systems.

Keywords: Superhydrophobic; Semicrystalline; Morphology; Solvent

Morphological control of polymerized n-octadecylsiloxane by Qiuping Lu; Tiange Hao; Qingping Ke; Wanjun Wang; Tao He; Xue-Mei Li (pp. 2080-2085).

Keywords: Superhydrophobic; Semicrystalline; Morphology; Solvent

Enhanced photo-induced hydrophilicity of the sol–gel-derived ZnO thin films by Na-doping by Jianguo Lü; Kai Huang; Xuemei Chen; Jianbo Zhu; Fanming Meng; Xueping Song; Zhaoqi Sun (pp. 2086-2090).

Na-doped ZnO thin films with different Na/Zn ratio were prepared by sol–gel method. The microstructure, chemical composition, surface morphology, and wettability of the thin films were investigated by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy, and water contact angle apparatus. The relation of wettability and Na/Zn ratio has been studied in detail. The wetting behavior of the thin films can be reversibly switched from hydrophobic to hydrophilic, through alternation of UV illumination and dark storage (or thermal treatment). Photo-induced hydrophilicity of the thin films increases with increasing Na/Zn ratio up to 0.08 and then decreases. The mechanism can be attributed to surface nanostructure and the concentration of Na doping.

Keywords: ZnO thin films; Photo-induced hydrophilicity; Nanostructure; Na doping

Development of long-life-cycle tablet ceramic adsorbent for geosmin removal from water solution by Rongzhi Chen; Qiang Xue; Zhenya Zhang; Norio Sugiura; Yingnan Yang; Miao Li; Nan Chen; Zhao Ying; Zhongfang Lei (pp. 2091-2096).

In this study, the tablet ceramic adsorbent (TCA), a silica/iron(III) oxide composite material, has been developed for geosmin (GSM) removal from the water solution. The physicochemical characteristics of TCA were examined with XRD, SEM, EDX and BET analyses. The sorption characteristics of GSM on TCA were investigated in a batch system. Attempts have been made to understand the adsorption kinetics, the effect of initial GSM concentration, solution pH, and reaction time.The batch experiments equilibrium data were well fitted to the Lagergren kinetic equation, which indicate the first-order nature adsorption. Over 82% of the GSM was removed by the TCA within 600min at an initial concentration of 200ng/L with 20g/L of TCA dose. The batch and regeneration study indicated that the TCA is a cost-effective GSM adsorbent with sufficient mechanical strength to retain its physical integrity after long-time adsorption, and high regeneration performance for long-life-cycle application. Almost no second contamination (toxic sludge or leached iron) was observed after adsorption, and the gas resultant of thermal regeneration is harmless to atmospheric environment.

Keywords: Geosmin adsorption; Tablet ceramic adsorbent; Sorption kinetics; Regeneration studies; Long-life-cycle

Synthesis, morphology and growth mechanism of brush-like ZnO nanostructures by Jie Wang; Huizhao Zhuang; Junlin Li; Peng Xu (pp. 2097-2101).

Polar surface dominated ZnO brush-like nanostructures have been successfully synthesized on Si substrates via a carbon-thermal reduction method at a temperature of 900°C. Specially, the axis of the as-prepared brush-like nanostructures is a straight nanorod along the [0001] direction and enclosed by six {011¯0} surfaces, which grew first; the sixfold symmetric nanonails were later formed along the equivalent a axes (<011¯0>) perpendicular to the central nanorod, and the brush is formed by epitaxial growth of nanonails on the central nanorod. The growth of the structures is based on firstly sprouting of nanorods and then epitaxial growth of nanonails in the six symmetric [011¯0] directions. Based on the testing results, the growth mechanism of the ZnO brush-like nanostructures was discussed, emphasizing the self-catalysed of ZnO and the polar orientation of ZnO nanostructures, and the formation of the nanonails may due to the different chances of absorbing the arriving vapors.

Keywords: Zinc oxide; Growth model; Characterization; Single crystal growth; Nanomaterials

Synthesis, morphology and growth mechanism of brush-like ZnO nanostructures by Jie Wang; Huizhao Zhuang; Junlin Li; Peng Xu (pp. 2097-2101).

Keywords: Zinc oxide; Growth model; Characterization; Single crystal growth; Nanomaterials

An interaction of helicid with liposome biomembrane by Rong Fan; Lihua Gan; Mingxian Liu; Dazhang Zhu; Liuhua Chen; Zijie Xu; Zhixian Hao; Longwu Chen (pp. 2102-2106).

An interaction of helicid with phosphatidylcholine liposome biomembrane was studied by transmission electron microscopy, UV–vis, fluorescence, Raman and³¹P NMR spectra. The results indicate that most of helicid molecules associate with liposomes at their surface and some of them penetrate the liposomes and locate in the hydrophobic regions of the membrane. The distribution coefficient K_D between liposome phases and aqueous phases is 13.5. The liposome becomes more dispersive and stable in the presence of helicid. The microenvironmental micropolarity and the microhydrophobicity of liposome membrane decrease with the increase of helicid concentration. The interaction of helicid molecules with liposome results in a slight decrease of the membrane longitudinal order, and an increase of the membrane lateral order. A model for the interaction of helicid with liposome biomembrane is proposed on the basis of the change of microenvironment parameters of liposome including the micropolarity, microhydrophobicity and membrane order. The change of microenvironment parameters results mainly from hydrogen bonding interaction between the hydroxyl groups of the pyranoside rings of helicid molecules and the polar head groups of phosphatidylcholine.

Keywords: Helicid; Liposome biomembrane; Interaction; Hydrogen bonding; Microenvironment parameters

An interaction of helicid with liposome biomembrane by Rong Fan; Lihua Gan; Mingxian Liu; Dazhang Zhu; Liuhua Chen; Zijie Xu; Zhixian Hao; Longwu Chen (pp. 2102-2106).

Keywords: Helicid; Liposome biomembrane; Interaction; Hydrogen bonding; Microenvironment parameters

The impact of ultra thin silicon nitride buffer layer on GaN growth on Si (111) by RF-MBE by Mahesh Kumar; Mohana K. Rajpalke; Basanta Roul; Thirumaleshwara N. Bhat; Neeraj Sinha; A.T. Kalghatgi; S.B. Krupanidhi (pp. 2107-2110).

Ultra thin films of pure silicon nitride were grown on a Si (111) surface by exposing the surface to radio-frequency (RF) nitrogen plasma with a high content of nitrogen atoms. The effect of annealing of silicon nitride surface was investigated with core-level photoelectron spectroscopy. The Si 2 p photoelectron spectra reveals a characteristic series of components for the Si species, not only in stoichiometric Si₃N₄ (Si⁴⁺) but also in the intermediate nitridation states with one (Si¹⁺) or three (Si³⁺) nitrogen nearest neighbors. The Si 2 p core-level shifts for the Si¹⁺, Si³⁺, and Si⁴⁺ components are determined to be 0.64, 2.20, and 3.05eV, respectively. In annealed sample it has been observed that the Si⁴⁺ component in the Si 2 p spectra is significantly improved, which clearly indicates the crystalline nature of silicon nitride. The high resolution X-ray diffraction (HRXRD), scanning electron microscopy (SEM) and photoluminescence (PL) studies showed a significant improvement of the crystalline qualities and enhancement of the optical properties of GaN grown on the stoichiometric Si₃N₄ by molecular beam epitaxy (MBE).

Keywords: Nitridation; MBE; Silicon nitride; GaN

Immobilization of immunoglobulin G in a highly oriented manner on a protein-A terminated multilayer system by Adem Zengin; Tuncer Caykara (pp. 2111-2117).

In this study, we have fabricated a multilayer system consisting of 3-glycidoxypropyldimethylmethoxysilane (GPDS), poly(dimethylsiloxane) bis 3-aminopropyl terminated (PDMS) and protein-A on a silicon wafer surface for oriented immobilization of immunoglobilin G (IgG). The multilayer system with a different component in each layer was characterized by ellipsometry, contact-angle goniometer, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) and fluorescence microscopy. The epoxy-terminated monolayer was formed by the chemisorption of GPDS molecules on the hydroxylated silicon surface. The PDMS film about 4.5nm thick was produced on the GPDS-monolayer by the chemical reaction between the amine groups at the end of PDMS chain and the epoxy groups of GPDS molecules. By introducing the PDMS chains, the hydrophilic character of GPDS-monolayer decreased. Study of the time dependence of polymer grafting showed that the chemisorption of GPDS is fast, whereas at least 16h is needed to generate the homogeneous PDMS layer. For immobilization of IgG molecules in a highly oriented manner, protein-A molecules were first chemically bound to an ultrathin (∼4.5nm) PDMS reactive polymer layer and later used to capture IgG. It was shown that the existence of protein-A in the multilayer system has a strong influence on the binding properties of IgG not only in the efficiency of binding, but also in its specificity. In conclusion, the multilayer system with protein-A has the potential to be further developed into an efficient immunoassay protein chip.

Keywords: Silicon wafers; 3-Glycidoxypropyldimethylmethoxysilane; Poly(dimethylsiloxane) bis 3-aminopropyl terminated; Protein-A; IgG immobilization

Immobilization of immunoglobulin G in a highly oriented manner on a protein-A terminated multilayer system by Adem Zengin; Tuncer Caykara (pp. 2111-2117).

Keywords: Silicon wafers; 3-Glycidoxypropyldimethylmethoxysilane; Poly(dimethylsiloxane) bis 3-aminopropyl terminated; Protein-A; IgG immobilization

Acrylic coatings exhibiting improved hardness, solvent resistance and glossiness by using silica nano-composites by Ahmad Dashtizadeh; Majid Abdouss; Hossein Mahdavi; Manuchehr Khorassani (pp. 2118-2125).

To prepare nano-composite emulsion acrylic resins with improved surface hardness and solvent resistance, nano-silica particles were treated with surfactants. The monomers of methyl methacrylate/butylacrylate were co-polymerized on the surface of dispersed silica particles. Several emulsions with different silica contents and copolymer mole fractions were prepared. Finally the emulsions were modified to water-based acrylic coatings and improved properties such as surface hardness, solvent resistance and glossiness were determined. The study of coatings was directed to find the improved resin by optimum surface properties. Size distribution and morphology of latexes were characterized by Fourier transform infrared spectroscopy, dynamic light scattering, transmission electron microscopy and scanning electron microscopy. The glass transition temperature of nano-composites was measured and discussed its relation with silica contents, monomer mole fractions and improved properties of coatings. The optimum pendulum hardness of coatings was on 0.46 methyl methacrylate mole fraction and 120g silica content. An increase in pendulum hardness of nano-composites with the addition of modified silica was observed. DLS and TEM studies indicate that silica particles were dispersed homogenously through the polymer matrix.

Keywords: Abbreviations; APS; ammonium peroxy disulfate; DBS; do decyl benzene sulfonic acid sodium salt; DLS; dynamic light scattering; FTIR; Fourier transform infrared spectroscopy; MAA; methacrylic acid; MMA; methyl methacrylate; DMF; di methyl formamid; BA; butyl acrylate; PEO200; polyethylene oxide 200; SEM; scanning electron microscopy; TEM; transmission electron microscopy; T; _g; glass transition temperatureLatex; Nano-composite; Solvent resistance; Hardness; Glossiness

Visible light sensitization effect of polyaminobenzoate adsorbed on TiO₂ nanocrystal surface by Puhong Wen; Sitao Yang; Yoshie Ishikawa; Hiroshi Itoh; Qi Feng (pp. 2126-2133).

Poly- o-aminobenzoate (POA) was prepared by oxidizing o-aminobenzoic acid with (NH₄)₂S₂O₈ in an acidic solution. POA was adsorbed on TiO₂ nanocrystal surface to obtain a POA–TiO₂ nanocomposite. The polymerization reaction, structure, adsorption reaction on TiO₂ surface, and visible light sensitization effect of the polymer adsorbed on TiO₂ surface were studied by FT-IR and UV–visible spectra, cyclic voltammetry, and measurements of visible light photoelectrochemical and photocatalytic activities. Three kinds of POA with different long conjugate structures can be formed. These polymers have large absorbance in wide visible light region. POA molecules can be adsorbed on TiO₂ surface by anchoring their carboxylate groups to the TiO₂ surface with a multi-bridging chelating mode, which causes formation of the POA–TiO₂ nanocomposite with a high stability. POA adsorbed on the TiO₂ nanocrystal showed high visible light sensitization effect in the photocatalytic reaction.

Keywords: Poly-; o; -aminobenzoate; Adsorption on TiO; ₂; Nanocomposite; Visible light sensitization effect

Visible light sensitization effect of polyaminobenzoate adsorbed on TiO₂ nanocrystal surface by Puhong Wen; Sitao Yang; Yoshie Ishikawa; Hiroshi Itoh; Qi Feng (pp. 2126-2133).

Keywords: Poly-; o; -aminobenzoate; Adsorption on TiO; ₂; Nanocomposite; Visible light sensitization effect

125MeV Si⁹⁺ ion irradiation of calcium phosphate thin film coated by rf-magnetron sputtering technique by K. Elayaraja; M.I. Ahymah Joshy; R.V. Suganthi; S. Narayana Kalkura; M. Palanichamy; M. Ashok; V.V. Sivakumar; P.K. Kulriya; I. Sulania; D. Kanjilal; K. Asokan (pp. 2134-2141).

Titanium substrate was coated with hydroxyapatite by radiofrequency magnetron sputtering (rf-magnetron sputtering) technique and subjected to swift heavy ion (SHI) irradiation of 125MeV with Si⁹⁺ at fluences of 1×10¹⁰, 1×10¹¹ and 1×10¹² ions/cm². The glancing incidence X-ray diffraction (GIXRD) analysis confirmed the HAp phase of the irradiated film. There was a considerable decrease in crystallinity and particle size after irradiation. In addition, DRS-UV reflectance spectra revealed a decrease in optical band gap ( E_g) from 5.2 to 4.6eV. Wettability of biocompatible materials plays an important role in biological cells proliferation for tissue engineering, drug delivery, gene transfer and bone growth. HAp thin films irradiated with 1×10¹¹ ions/cm² fluence showed significant increase in wettability. While the SHI irradiated samples exhibited enhanced bioactivity, there was no significant variation in cell viability. Surface roughness, pores and average particle size were analyzed by atomic force microscopy (AFM).

Keywords: Biomaterials; rf-magnetron sputtering; Ion beam irradiation; Cell viability; HAp

ToF-SIMS and XPS study of ancient papers by Francesca Benetti; Nadia Marchettini; Andrea Atrei (pp. 2142-2147).

The surface composition of 18th century papers was investigated by means of ToF-SIMS and XPS. The aim of the present study was to explore the possibility of using these surface sensitive methods to obtain information which can help to determine the manufacturing process, provenance and state of conservation of ancient papers. The ToF-SIMS results indicate that the analyzed papers were sized by gelatin and that alum was added as hardening agent. The paper sheets produced in near geographical areas but in different paper mills exhibit a similar surface composition and morphology of the fibers as shown by the ToF-SIMS measurements. The ToF-SIMS and the XPS results indicate that a significant fraction of the cellulose fibers is not covered by the gelatin layer. This was observed for the ancient papers and for a modern handmade paper manufactured according to the old recipes.

Keywords: ToF-SIMS; XPS; Ancient paper; Surface analysis

ToF-SIMS and XPS study of ancient papers by Francesca Benetti; Nadia Marchettini; Andrea Atrei (pp. 2142-2147).

Keywords: ToF-SIMS; XPS; Ancient paper; Surface analysis

Flame treatment on plastic: A new surface free energy statistical prediction model and characterization of treated surfaces by L. Mazzola; E. Bemporad; F. Carassiti (pp. 2148-2158).

Flame treatments on polymeric materials improve surface free energy (SFE) and consequently the wettability and adhesion of coatings, metallizations, varnish and glues. In this paper, using a statistical methodological approach based on DoE technique and multivariate analysis of flame treatment process parameters, a mathematical model of SFE and wettability is obtained.Contact angle experimental technique was applied to measure the improvement of wettability and SFE.In order to study the oxygen diffusion within the polymer, morphological variation and change of its structure, analyses of treated surface sample were carried out on micro and nano scales.X-ray photoelectron spectroscopy analysis, performed before and after flame treatment, showed the O-radical group improvement on a polymeric surface.Focused ion beam and transmission electron microscopy technology were used to determine the exact thickness of the polymeric material influenced by flame treatment, identifying a composite change on nano scale and a porosity change on microscale.

Keywords: Flame treatment; Design of experiment; Focused ion beam; X-ray photoelectron spectroscopy; Transmission electron microscopy

Flame treatment on plastic: A new surface free energy statistical prediction model and characterization of treated surfaces by L. Mazzola; E. Bemporad; F. Carassiti (pp. 2148-2158).

Keywords: Flame treatment; Design of experiment; Focused ion beam; X-ray photoelectron spectroscopy; Transmission electron microscopy

Protective sol–gel coating on silicate phosphor used in light emitting diodes by J.P. Kim; S.B. Song (pp. 2159-2163).

In this study, an orange-red silicate phosphor that is used in light emitting diodes (LEDs) was coated with a SiO₂ blocking layer via a sol–gel reaction of tetra-ethyl ortho-silicate (TEOS) to investigate its reliability as an encapsulant. A sol–gel coating protects the phosphor surface from moisture and reactive materials and improves the reliability of the phosphor. The efficacy of the phosphor coating following an 85°C and 85 relative humidity (Rh)% test decreased by 7%, whereas an uncoated phosphor coating decreased by 35%. A SiO₂ sol–gel coating decreases the luminous efficiency by a small amount with each coating.

Keywords: Phosphor; LED; Sol–gel coating; Reliability; Encapsulant

Protective sol–gel coating on silicate phosphor used in light emitting diodes by J.P. Kim; S.B. Song (pp. 2159-2163).

Keywords: Phosphor; LED; Sol–gel coating; Reliability; Encapsulant

Cocktail effect of Fe₂O₃ and TiO₂ semiconductors for a high performance dye-sensitized solar cell by Ji Sun Im; Sung Kyu Lee; Young-Seak Lee (pp. 2164-2169).

The bi-semiconductors of TiO₂ and Fe₂O₃ were used as a photoelectrode material in a high performance dye-sensitized solar cell due to cocktail effects from the two conduction bands. The size of the semiconductors was reduced by using a paint shaker to enlarge the contact area of the semiconductor with the dye or electrolyte. The fill factor and the efficiency of the prepared dye-sensitized solar cell were improved by over 16% and 300%, respectively; these parameters were measured from a current–voltage curve that was based on the effects of the Fe₂O₃ co-semiconductor and the size reduction. A mechanism is suggested wherein the conduction band of Fe₂O₃ works to prohibit the trapping effects of electrons in the conduction band of TiO₂. This result is attributed to the prevention of electron recombination between electrons in the TiO₂ conduction band with dye or electrolytes. The mechanism is suggested based on impedance results, which indicate improved electron transport at the interface of the TiO₂/dye/electrolyte.

Keywords: Dye-sensitized solar cell; TiO; ₂; Fe; ₂; O; ₃; Electrochemical property; Size reduction

Cocktail effect of Fe₂O₃ and TiO₂ semiconductors for a high performance dye-sensitized solar cell by Ji Sun Im; Sung Kyu Lee; Young-Seak Lee (pp. 2164-2169).

Keywords: Dye-sensitized solar cell; TiO; ₂; Fe; ₂; O; ₃; Electrochemical property; Size reduction

Preparation of long-afterglow colloidal solution of Sr₂MgSi₂O₇: Eu²⁺, Dy³⁺ by laser ablation in liquid by Fumitaka Yoshimura; Kazutaka Nakamura; Fumihiro Wakai; Masahiko Hara; Mamoru Yoshimoto; Osamu Odawara; Hiroyuki Wada (pp. 2170-2175).

We have successfully prepared a novel nanoparticle solution of Sr₂MgSi₂O₇: Eu²⁺, Dy³⁺ with afterglow properties by means of laser ablation in liquid. This process also produced by-products of different kinds, depending on the liquid used. The amount of by-product and the size of the nanoparticles were controlled by the energy density of laser ablation. The amount of by-product was reduced by a decrease in the energy density, which also decreased the particle size of the nanoparticles. The PL spectrum of the nanoparticles was the same as that of the target materials used for laser ablation. The afterglow properties deteriorated with a decrease in particle size. We concluded that an increase in specific surface area caused by a decrease in particle size resulted in the decrease of luminescent intensity.

Keywords: Laser ablation; Nanoparticle; Photoluminescence; Afterglow

Photovoltaic properties of the copper-phthalocyanine and ZnO nanorod array system affected by ethanol by Yiting Liu; Aimin Liu; Weifeng Liu; Yongchang Sang; Zengquan Hu; Dawei Kang (pp. 2176-2179).

Well-aligned ZnO nanorod array, fabricated on conductive indium-tin-oxide (ITO) substrate by wet chemical bath deposition (CBD) method, was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Surface photovoltage (SPV) technique was employed to study the photovoltaic properties of the copper-phthalocyanine (CuPc) and ZnO nanorod array system affected by ethanol. Prior to ethanol adsorption, two pronounced SPV response bands were exhibited for this system in the range 300–410 and 540–760nm, respectively. Post-adsorption measurements reveal that the SPV intensity of the former band is enhanced, while that of the latter band is suppressed if ethanol was used to modify CuPc surface. Moreover, both of the SPV intensity of two response bands is enhanced if ethanol was used to modify ZnO and CuPc interface. Mechanisms of these phenomena were suggested.

Keywords: Surface photovoltage; Ethanol; Copper-phthalocyanine; ZnO nanorod array; Charge separation

Photovoltaic properties of the copper-phthalocyanine and ZnO nanorod array system affected by ethanol by Yiting Liu; Aimin Liu; Weifeng Liu; Yongchang Sang; Zengquan Hu; Dawei Kang (pp. 2176-2179).

Keywords: Surface photovoltage; Ethanol; Copper-phthalocyanine; ZnO nanorod array; Charge separation

Research on Si–Al based catalysts prepared by complete liquid-phase method for DME synthesis in a slurry reactor by Zhihong Li; Zhijun Zuo; Wei Huang; Kechang Xie (pp. 2180-2183).

A series of Si–Al based DME synthesis catalysts were prepared by complete liquid-phase method and characterized by in situ XPS, XRD, N₂ adsorption and NH₃-TPD analyses. Based on the results, the addition of Si could adjust the pore structure and surface acidity of catalyst, exhibiting a strong promoting effect on the CO conversion and DME selectivity. However, when Si/Al ratio is higher, Si would cover active sites and increase the amount of strong acidity sites, causing the reduction in catalytic activity. It was found from in situ XPS characterization that Cu⁰ is the active center of methanol synthesis in DME production, and the addition of Si changes the chemical surroundings of active components and weaken the interaction between Cu, Zn and Al, which maybe give rise to the decrease in catalyst stability.

Keywords: DME; Slurry reactor; Complete liquid-phase method; Si–Al based catalyst

Research on Si–Al based catalysts prepared by complete liquid-phase method for DME synthesis in a slurry reactor by Zhihong Li; Zhijun Zuo; Wei Huang; Kechang Xie (pp. 2180-2183).

Keywords: DME; Slurry reactor; Complete liquid-phase method; Si–Al based catalyst

Toughening of Fe-based laser-clad alloy coating by Chengwu Yao; Jian Huang; Peilei Zhang; Zhuguo Li; Yixiong Wu (pp. 2184-2192).

An investigation is reported on crack-free laser clad Fe-based alloy by use of biaxial powder feeding shielded with argon gas. The microstructure and phase structure of the coating were studied, and mechanical properties were analyzed through hardness, tension strength and wear resistance of the coating. Microstructure analysis showed that there was retained austenite with spherical particles distributed therein in the interdendritic and nearby grain boundary regions. The mechanical test results showed that net-like distributed retained austenite in the interdendritic region had certain toughening effect through blunting crack-tip. Under wear condition of high sliding speed and high loading, the wear resistance of the coating with net-like retained austenite was much higher than that of the coating with some discontinuous carbide network or carbide blocks. The results showed that toughening of laser clad Fe-based alloy with high hardness over 850HV could be achieved by modifying interdendritic phases from net-like carbide to net-like austenite with spherical particles.

Keywords: Key words; Laser cladding; Fe-based coating; Retained austenite; Interdendritic region

Toughening of Fe-based laser-clad alloy coating by Chengwu Yao; Jian Huang; Peilei Zhang; Zhuguo Li; Yixiong Wu (pp. 2184-2192).

Keywords: Key words; Laser cladding; Fe-based coating; Retained austenite; Interdendritic region

CuInS₂ thin films obtained through the annealing of chemically deposited In₂S₃–CuS thin films by Y. Peña; S. Lugo; M. Calixto-Rodriguez; A. Vázquez; I. Gómez; P. Elizondo (pp. 2193-2196).

In this work, we report the formation of CuInS₂ thin films on glass substrates by heating chemically deposited multilayers of copper sulfide (CuS) and indium sulfide (In₂S₃) at 300 and 350°C in nitrogen atmosphere at 10Torr. CIS thin films were prepared by varying the CuS layer thickness in the multilayers with indium sulfide. The XRD analysis showed that the crystallographic structure of the CuInS₂ (JCPDS 27-0159) is present on the deposited films. From the optical analysis it was estimated the band gap value for the CIS film (1.49eV). The electrical conductivity varies from 3×10⁻⁸ to 3Ω⁻¹cm⁻¹ depending on the thickness of the CuS film. CIS films showed p-type conductivity.

Keywords: CuInS; ₂; Thin Films; Chemical bath deposition

Growth, microstructure and electrical properties of sputter-deposited hafnium oxide (HfO₂) thin films grown using a HfO₂ ceramic target by B. Aguirre; R.S. Vemuri; D. Zubia; M.H. Engelhard; V. Shutthananadan; K. Kamala Bharathi; C.V. Ramana (pp. 2197-2202).

Hafnium oxide (HfO₂) thin films have been made by radio-frequency (rf) magnetron-sputtering onto Si(100) substrates under varying growth temperature ( T_s). HfO₂ ceramic target has been employed for sputtering while varying the T_s from room temperature to 500°C during deposition. The effect of T_s on the growth and microstructure of deposited HfO₂ films has been studied using grazing incidence X-ray diffraction (GIXRD), and high-resolution scanning electron microscopy (HR-SEM) coupled with energy dispersive X-ray spectrometry (EDS). The results indicate that the effect of T_s is significant on the growth, surface and interface structure, morphology and chemical composition of the HfO₂ films. Structural characterization indicates that the HfO₂ films grown at T_s<200°C are amorphous while films grown at T_s>200°C are nanocrystalline. An amorphous-to-crystalline transition occurs at T_s=200°C. Nanocrystalline HfO₂ films crystallized in a monoclinic structure with a (−111) orientation. An interface layer (IL) formation occurs due to reaction at the HfO₂–Si interface for HfO₂ films deposited at T_s>200°C. The thickness of IL increases with increasing T_s. EDS at the HfO₂–Si cross-section indicate that the IL is a (Hf, Si)–O compound. The electrical characterization using capacitance–voltage measurements indicate that the dielectric constant decreases from 25 to 16 with increasing T_s. The current–voltage characteristics indicate that the leakage current increases significantly with increasing T_s due to increased ILs.

Keywords: Hafnium oxide; Thin films; Microstructure; Dielectric constant

A novel method for improving the adhesion strength of the electrodeposited Ni films in MEMS by Hong Wang; Rui Liu; Wei Qiao Jiang; Jun Zhu; Jian Zhi Feng; Gui Fu Ding; Xiaolin Zhao (pp. 2203-2207).

Adhesion performance of MEMS materials is increasingly important with the widely use of miniaturized devices. This paper proposed a novel method for improving adhesion performance between electrodeposited Ni multi-layers. The new method is to treat the Ni substrate in nickel chloride plating solution by pulse reverse current technique before electrodeposition. The dense oxide film of Ni substrate can be removed effectively by this electrochemical method, meanwhile, the proper roughness of Ni substrate is in favor of epitaxial growth during electrodeposition. Moreover, the Ni film is electrodeposited by the new method with low stress and coarse crystal grain. Consequently, the adhesion performance of Ni films is improved dramatically. The experimental results show that the adhesion performance of Ni film electrodeposited by the new method is about 3 times that of by traditional method.

Keywords: Adhesion strength; MEMS; Electrodeposition; Pulse reverse

A novel method for improving the adhesion strength of the electrodeposited Ni films in MEMS by Hong Wang; Rui Liu; Wei Qiao Jiang; Jun Zhu; Jian Zhi Feng; Gui Fu Ding; Xiaolin Zhao (pp. 2203-2207).

Keywords: Adhesion strength; MEMS; Electrodeposition; Pulse reverse

Effects of post-thermal annealing temperature on the optical and structural properties of gold particles on silicon suboxide films by Keewah Chan; Zarina Aspanut; Boontong Goh; Chornghaur Sow; Binni Varghese; Saadah Abdul Rahman; Muhamad Rasat Muhamad (pp. 2208-2213).

In this work, silicon suboxide (SiO_x) thin films were deposited using a RF magnetron sputtering system. A thin layer of gold (Au) with a thickness of about 10nm was sputtered onto the surface of the deposited SiO_x films prior to the thermal annealing process at 400°C, 600°C, 800°C and 1000°C. The optical and structural properties of the samples were studied using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and optical transmission and reflection spectroscopy. SEM analyses demonstrated that the samples annealed at different temperatures produced different Au particle sizes and shapes. SiO_x nanowires were found in the sample annealed at 1000°C. Au particles induce the crystallinity of SiO_x thin films in the post-thermal annealing process at different temperatures. These annealed samples produced silicon nanocrystallites with sizes of less than 4nm, and the Au nanocrystallite sizes were in the range of 7–23nm. With increased annealing temperature, the bond angle of the Si–O bond increased and the optical energy gap of the thin films decreased. The appearance of broad surface plasmon resonance absorption peaks in the region of 590–740nm was observed due to the inclusion of Au particles in the samples. The results show that the position and intensity of the surface plasmon resonance peaks can be greatly influenced by the size, shape and distribution of Au particles.

Keywords: Silicon suboxide; Gold particle; Post-thermal annealing; Surface plasmon resonance

Multilayer Bi_1.5Zn_1.0Nb_1.5O₇/Ba_0.6Sr_0.4TiO₃/Bi_1.5Zn_1.0Nb_1.5O₇ thin films for tunable microwave applications by Jitendra Singh; S.B. Krupanidhi (pp. 2214-2217).

Bi_1.5Zn_1.0Nb_1.5O₇/Ba_0.6Sr_0.4TiO₃/Bi_1.5Zn_1.0Nb_1.5O₇ tunable multilayer thin film has been fabricated by pulsed laser ablation and characterized. Phase composition and microstructure of multilayer films were characterized by X-ray diffraction, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The film has very smooth surface with RMS roughness of 1.5–2nm and grain size of 100–150nm. Total film thickness has been measure to be 375nm. The BZN thin films at 300K, on Pt(111)/SiO₂/Si substrate showed zero-field dielectric constant of 105 and dielectric loss tangent of 0.002 at frequency of 0.1MHz. Thin films annealed at 700°C shows the dielectric tunability of 18% with biasing field 500kV/cm at 0.1MHz. The multilayer thin film shows nonferroelectric behavior at room temperature. The good physical and electrical properties of multilayer thin films make them promising candidate for tunable microwave device applications.

Keywords: Pulsed laser deposition; Perovskite; Dielectric materials; Ferroelectric materials

Multilayer Bi_1.5Zn_1.0Nb_1.5O₇/Ba_0.6Sr_0.4TiO₃/Bi_1.5Zn_1.0Nb_1.5O₇ thin films for tunable microwave applications by Jitendra Singh; S.B. Krupanidhi (pp. 2214-2217).

Keywords: Pulsed laser deposition; Perovskite; Dielectric materials; Ferroelectric materials

Minimizing permeability of PET substrates using Oxygen plasma treatment by Z. Sanaee; S. Mohajerzadeh; K. Zand; F.S. Gard; H. Pajouhi (pp. 2218-2225).

Surface plasma treatment in a reactive ion etching system is used to observe a considerable decrease in permeability of polyethylene terephthalate to gases. The effects of oxygen plasma on the surface properties and morphology of PET polymers are investigated by scanning electron microscopy (SEM), x-ray photo-electron spectroscopy (XPS) and atomic force microscopy (AFM). In addition, the optical transmission properties of the treated samples have been investigated corroborating the findings of SEM and AFM analyses. Moreover, the penetration of air through the treated substrates was investigated using a vacuum test. The treated PET substrates can be used to realize flexible plasma display panels.

Keywords: PET; Treatment; Permeability; Plasma; Display

Minimizing permeability of PET substrates using Oxygen plasma treatment by Z. Sanaee; S. Mohajerzadeh; K. Zand; F.S. Gard; H. Pajouhi (pp. 2218-2225).

Keywords: PET; Treatment; Permeability; Plasma; Display

Growth characteristics of inclined columns produced by Glancing Angle Deposition (GLAD) and colloidal lithography by A. Dolatshahi-Pirouz; D.S. Sutherland; M. Foss; F. Besenbacher (pp. 2226-2230).

Nanocolumns were produced by performing Glancing Angle Deposition (GLAD) onto self-assembled template arrays consisting of platinum coated polystyrene spheres. By varying the angle of incidence ( θ=35°, 10° and 5°) and the deposited surface mass density it was possible to control the shape of the individual columns. The changes in column shape as function of the amount of mass deposited on the respective surfaces were characterized by monitoring the increase in the length and width of the structures. Interestingly the column shape development followed a power law behaviour. The power law exponents retrieved from the length and width increment as function of the deposited surface mass density decreased from 1.06 to 0.46 and 0.71 to 0.09, respectively, as θ changed from 35° to 5°. The changes in the power law exponents indicate that the growth of the nano-columns is influenced by both surface diffusion and shadowing effects. A detailed understanding of the underlying processes governing the nanocolumn growth might be utilized in the design of new functional nanomaterials.

Keywords: Platinum; Power law scaling; Glancing Angle Deposition; Nanostructures; Thin films; Colloidal lithography

Growth characteristics of inclined columns produced by Glancing Angle Deposition (GLAD) and colloidal lithography by A. Dolatshahi-Pirouz; D.S. Sutherland; M. Foss; F. Besenbacher (pp. 2226-2230).

Keywords: Platinum; Power law scaling; Glancing Angle Deposition; Nanostructures; Thin films; Colloidal lithography

Fabrication and characterization of rod-like nano-hydroxyapatite on MAO coating supported on Mg–Zn–Ca alloy by J.H. Gao; S.K. Guan; J. Chen; L.G. Wang; S.J. Zhu; J.H. Hu; Z.W. Ren (pp. 2231-2237).

The poor corrosion resistance of magnesium alloys is a dominant problem that limits their clinical application. In order to solve this challenge, micro-arc oxidation (MAO) was used to fabricate a porous coating on magnesium alloys and then electrochemical deposition (ED) was done to fabricate rod-like nano-hydroxyapatite (RNHA) on MAO coating. The cross-section morphology of the composite coatings and its corresponding energy dispersion spectroscopy (EDS) surficial scanning map of calcium revealed that HA rods were successfully deposited into the pores. The three dimensional morphology and scanning electron microscopy (SEM) image of the composite coatings showed that the distribution of the HA rods was dense and uniform. Atomic force microscope (AFM) observation of the composite coatings showed that the diameters of HA rods varied from 95nm to 116nm and the root mean square roughness (RMS) of the composite coatings was about 42nm, which were favorable for cellular survival. The bonding strength between the HA film and MAO coating increased to 12.3MPa, almost two times higher than that of the direct electrochemical deposition coating (6.3MPa). Compared with that of the substrate, the corrosion potential of Mg–Zn–Ca alloy with composite coatings increased by 161mV and its corrosion current density decreased from 3.36×10⁻⁴A/cm² to 2.40×10⁻⁷A/cm² which was due to the enhancement of bonding strength and the deposition of RNHA in the MAO pores. Immersion tests were carried out at 36.5±0.5°C in simulated body fluid (SBF). It was found that RNHA can induce the rapid precipitation of calcium orthophosphates in comparison with conventional HA coatings. Thus magnesium alloy coated with the composite coatings is a promising candidate as biodegradable bone implants.

Keywords: Nano-HA; MAO coating; Electrochemical deposition; Immersion test

Influence of pores on the surface microcompression mechanical response of thermal barrier coatings fabricated by atmospheric plasma spray—Finite element simulation by L. Wang; Y. Wang; X.G. Sun; Z.Y. Pan; J.Q. He; C.G. Li (pp. 2238-2249).

Surface microcompression is a very important technique to characterize the mechanical properties of film and coating systems. In this paper, surface microcompression simulation for La₂Zr₂O₇ (LZ) thermal barrier coatings (TBCs) was implemented by finite element method, especially, the influence of pores on the surface microcompression mechanical response of the thermal barrier coatings fabricated by atmospheric plasma spray (APS) was focused on. The simulation results indicate that the pores not only affect the stress distribution beneath the contact area between the indenter and coating surface, but also affect the shape of the force–displacement curve and the plastic deformation behavior of TBCs. The micromechanism was discussed in detail in this study. At the same time, by using the surface microcompression technique, a new direction or method was proposed to characterize the pore content of the coating quantitatively.

Keywords: Thermal barrier coatings; Microcompression; Pore; Finite element

Effects on the field emission properties by variation in surface morphology of patterned photosensitive carbon nanotube paste using organic solvent by Woo-Sung Cho; Yang Doo Lee; Jinnil Choi; Jong Hun Han; Byeong-Kwon Ju (pp. 2250-2253).

Display Omitted▶ Photosensitive carbon nanotube (CNT) paste is fabricated by CNTs, UV-sensitive binder solution, and Ag as filler additives. ▶ Acetone removed the organic binder material from the patterns. ▶ Acetone can be used an efficient developer for photosensitive CNT pastes.Photosensitive carbon nanotube (CNT) paste was prepared by 3-roll milling of multi-walled carbon nanotubes (MWNTs), UV-sensitive binder solution, and Ag as filler additives. Arrays of MWNT dots with a diode structure were fabricated by a combination of screen printing method and photolithography using these paste, and acetone utilized as the developer. The MWNT dots were well-defined and the organic binder materials in the dots were partially removed. The MWNT film without a heat treatment showed a high current density of 1.35mA/cm² at 3.25V/μm and low turn-on field of 2.2V/μm at 100μA/cm². Acetone can be used as an efficient developer to form patterns and to remove the organic residues in patterns, simultaneously.

Keywords: Field emission; Carbon nanotubes; Multi-walled carbon nanotube; Organic binder

Physical properties of polycrystalline Cr-doped SnO₂ films grown on glasses using reactive dc magnetron co-sputtering technique by Shiu-Jen Liu; Liang-Yu Chen; Chai-Yun Liu; Hau-Wei Fang; Jang-Hsing Hsieh; Jenh-Yih Juang (pp. 2254-2258).

▶ Cr-doped SnO₂ films were fabricated on glass substrates using dc magnetron co-sputtering technique. ▶ The valence of Cr doped in SnO₂ films is determined to be 3+ by XPS measurement. ▶ The electrical, optical and magnetic properties of the co-sputtered films were found to be strongly affected by Cr doping. ▶ The co-sputtered Cr-doped SnO₂ films exhibit paramagnetic characteristics from room temperature down to 25K.Electrical, optical and magnetic properties of polycrystalline Cr-doped SnO₂ films grown on glasses using reactive dc magnetron co-sputtering technique were investigated. The Cr content was modulated by varying the sputtering power applied on the Cr target. The carrier concentration and conductivity of doped films are reduced with increasing the Cr doping. Moreover, while the Cr content ratio Cr/(Sn+Cr) exceeds 0.9at.%, the doped SnO₂ films become insulators and the optical transmission is strongly affected. The surface roughness of sputtered films is also increased by Cr doping. The co-sputtered Cr-doped SnO₂ films exhibit paramagnetic characteristics from room temperature down to 25K.

Keywords: Cr-doped SnO; ₂; films; Co-sputtering technique; Optoelectronic properties; Paramagnetism

Microstructure and properties of 6FeNiCoSiCrAlTi high-entropy alloy coating prepared by laser cladding by Hui Zhang; Ye Pan; Yizhu He; Huisheng Jiao (pp. 2259-2263).

▶ The 6FeNiCoSiCrAlTi high-entropy alloy coating with simple BCC solid solution phase has been successfully laser cladded on a low carbon steel substrate. ▶ The tendency of component segregation in the solidification microstructure of multi-component alloy is effectively relieved by laser cladding. ▶ There are lots of abnormal low angle grain boundaries distributed in the coatings. ▶ The coating shows high microhardness and excellent soft magnetic properties.The content of each constituent element in the newly developed high-entropy alloys (HEAs) is always restricted in equimolar or near-equimolar ratio in order to avoid the formation of complex brittle phases during the solidification process. In this study, a 6FeNiCoSiCrAlTi high-entropy alloy coating with simple BCC solid solution phase has been prepared by laser cladding on a low carbon steel substrate. The microstructure, hardness and magnetic properties have been investigated. The experimental results show that the tendency of component segregation in the conventional solidification microstructure of multi-component alloy is effectively relieved. The microstructure of the coating is mainly composed of equiaxed polygonal grains, discontinuous interdendritic segregation and nano-precipitates. EBSD observation confirms that the polygonal grains and interdendritic segregation have similar BCC structure with lots of low angle grain boundaries at the interface. The microhardness of the coating reaches 780 HV_0.5, which is much higher than most of the HEAs prepared by other methods. In addition, the coating shows excellent soft magnetic properties.

Keywords: Laser cladding; High-entropy alloy; Microstructure; Hardness; Magnetic properties

Microstructure and properties of 6FeNiCoSiCrAlTi high-entropy alloy coating prepared by laser cladding by Hui Zhang; Ye Pan; Yizhu He; Huisheng Jiao (pp. 2259-2263).

Keywords: Laser cladding; High-entropy alloy; Microstructure; Hardness; Magnetic properties

Synthesis and H₂ sensing properties of aligned ZnO nanotubes by Yanxia Liu; Caitian Gao; Xiaojun Pan; Xiuyun An; Yizhu Xie; Ming Zhou; Jie Song; Hongliang Zhang; Zhaoyu Liu; Qin Zhao; Yonghai Zhang; Erqing Xie (pp. 2264-2268).

Aligned ZnO nanotubes with the outer radius of about 200nm were synthesized by a two-step approach, which involves electrospinning and sputtering techniques. The ZnO nanotubes are polycrystalline hexagonal structure, indicted by XRD and TEM analysis. The ZnO nanotubes show sensing property to H₂. The sensor response of the aligned nanotubes to 100ppm H₂ increases from 2.3 to 3.6 with the temperature increasing from 200 to 400°C. Beside, the sensor response of the ZnO nanotubes increases compared with that of the ZnO film prepared under the same condition.

Keywords: ZnO nanotubes; Electrospinning; Sputtering; H; ₂; sensing property

Composition, microstructure, and properties of CrN_x films deposited using medium frequency magnetron sputtering by Qinghua Kong; Li Ji; Hongxuan Li; Xiaohong Liu; Yongjun Wang; Jianmin Chen; Huidi Zhou (pp. 2269-2274).

▶ CrN_x films with excellent mechanical and tribological properties were deposited using medium frequency magnetron sputtering with different N₂ contents. ▶ The phases in the as-deposited CrN_x films change from Cr(N)+Cr₂N to single-phase Cr₂N, and then Cr₂N+CrN to single-phase CrN as a function of N₂ content. ▶ The surface morphologies strongly depend on the N₂ content and the as-deposited CrN_x films exhibit typical columnar structure. ▶ Cr₂N films show higher hardness than CrN films, whereas CrN films exhibit lower friction coefficient.CrN_x films were deposited on stainless steel and Si (111) substrates via medium frequency magnetron sputtering in a N₂+Ar mixed atmosphere. The influence of N₂ content on the deposition rate, composition, microstructure, mechanical and tribological properties of the as-deposited films was investigated by means of the X-ray photoelectron spectrometry (XPS), X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), nanoindentation and tribometer testing. It was found that the N atomic concentration increased and the phase transformed from a mixture of Cr₂N+Cr(N) to single-phase Cr₂N, and then Cr₂N+CrN to pure CrN phase with the increase of N₂ content. The Cr 2p_3/2 and N 1s of XPS spectra also confirmed the evolution of phase. Accordingly, all films exhibited a typical columnar structure which lies in the zone T of Thornton Model. The mixed Cr₂N and Cr(N) phases showed low hardness and high friction coefficient. Cr₂N possessed higher hardness than CrN while CrN exhibited lower friction coefficient.

Keywords: CrN; _x; films; Medium frequency magnetron sputtering; N; ₂; content; Microstructure; Mechanical properties; Tribological properties

Preparation and performance of photocatalytic TiO₂ immobilized on palladium-doped carbon fibers by Yaofeng Zhu; Yaqin Fu; Qing-Qing Ni (pp. 2275-2280).

Pd-modified carbon fibers (CFs) are obtained by a facile oxidation–reduction method and then dip-coated in a sol–gel of titanium dioxide (TiO₂) to form supported TiO₂/Pd-CF photocatalysts. The morphology of the Pd-modified CFs and the amount Pd deposited are characterized by field emission scanning electron microscopy and atomic absorption spectrometry, respectively. X-ray diffraction is used to investigate the crystal structures of the TiO₂ photocatalyst. Acid orange II is used as a model contaminant to evaluate the photocatalytic properties of the photocatalyst under UV irradiation. TiO₂/Pd-CF exhibits higher catalytic activity than TiO₂/CF towards the degradation of acid orange II. Optimum photocatalytic performance and support properties are achieved when the Pd particle loading is about 10.8mg/g.

Keywords: Titanium dioxide; Pd particles; Carbon fiber; Photocatalytic; Acid orange

Preparation and performance of photocatalytic TiO₂ immobilized on palladium-doped carbon fibers by Yaofeng Zhu; Yaqin Fu; Qing-Qing Ni (pp. 2275-2280).

Keywords: Titanium dioxide; Pd particles; Carbon fiber; Photocatalytic; Acid orange

Controlling precursor stability and evaporation through molecular design. Pseudo single source precursor approach to MOCVD SrTiO₃ thin films by Gulaim A. Seisenbaeva; Suresh Gohil; Vadim G. Kessler; Michel Andrieux; Corinne Legros; Patrick Ribot; M. Brunet; E. Scheid (pp. 2281-2290).

Strontium titanate SrTiO₃ thin films have attracted interest as a possible gate dielectric material. Preparation of its high quality coatings is hindered by difference in volatility of the homometallic precursors – strontium beta-diketonates and titanium alkoxides. The only earlier known single-source precursor, a sec-alkoxide derivative Sr₂Ti₂(thd)₄(OiPr)₈, has limited volatility. Bimetallic primary alkyl chain complexes, Sr₄Ti₂O(thd)₄(OR)₁₀(ROH)₂, R=Et,ⁿPr, are stable and volatile, but possess a wrong composition. Highly volatile precursor Sr₂Ti₂(thd)₄(OⁱBu)₈ has been prepared using an iso-alkoxide, combining proper ligand size with the sterical requirements, and characterized by multivariate evaporation analysis. Its evaporation is associated with complete decomposition into homometallic species, which, however, are evaporated in a single step. This permits to successfully use this novel precursor for SrTiO₃ thin film deposition by DLI-MOCVD technique in a sufficiently broad established temperature range. Using optimized experimental conditions, 100nm thick strontium titanate films with high permittivity have been successfully obtained on (100) Si.

Keywords: Strontium titanate (STO); Volatility studies; Gas phase behaviour; Solution stability; Deposition optimization

Molar concentration–depth profiles at the solution surface of a cationic surfactant reconstructed with angle resolved X-ray photoelectron spectroscopy by Chuangye Wang; Harald Morgner (pp. 2291-2297).

Display Omitted▶ By a refined calculation procedure and with the evaluated partial molar volumes of the surfactant and the solvent, the molar concentration-depth profiles of surfactant ions have been reconstructed by angle resolved photoelectron spectroscopy. ▶ The anionic molar concentration-depth profiles and surface excesses have good agreements with their counterparts determined by neutral impact ion scattering spectroscopy.In the current work, we first reconstructed the molar fraction–depth profiles of cation and anion near the surface of tetrabutylammonium iodide dissolved in formamide by a refined calculation procedure, based on angle resolved X-ray photoelectron spectroscopy experiments. In this calculation procedure, both the transmission functions of the core levels and the inelastic mean free paths of the photoelectrons have been taken into account. We have evaluated the partial molar volumes of surfactant and solvent by the densities of such solutions with different bulk concentrations. With those partial molar volumes, the molar concentration–depth profiles of tetrabutylammonium ion and iodide ion were determined. The surface excesses of both surfactant ions were then achieved directly by integrating these depth profiles. The anionic molar concentration–depth profiles and surface excesses have been compared with their counterparts determined by neutral impact ion scattering spectroscopy. The comparisons exhibit good agreements. Being capable of determining molar concentration–depth profiles of surfactant ions by core levels with different kinetic energies may extend the applicable range of ARXPS in investigating solution surfaces.

Keywords: Angle resolved X-ray photoelectron spectroscopy; Cationic surfactant solution; Fraction–depth profiles; Partial molar volume; Molar concentration–depth profiles

Optical and structural properties of pulsed laser ablation deposited ZnO thin film by E. Fazio; A.M. Mezzasalma; G. Mondio; T. Serafino; F. Barreca; F. Caridi (pp. 2298-2302).

A limited number of reports exists in the literature concerning the systematic study of the structural and optical properties of ZnO thin films, produced by pulsed laser ablation, in correlation with the deposition parameters adopted. In this paper we present a characterization of a sample prepared by this technique and studied by photoelectron spectroscopy and X-ray diffraction. The dielectric function of both target and films has been deduced by reflection electron energy loss spectroscopy.

Keywords: Pulsed laser ablation; Reflection electron energy loss spectroscopy; Zinc oxide; Thin films

Optical and structural properties of pulsed laser ablation deposited ZnO thin film by E. Fazio; A.M. Mezzasalma; G. Mondio; T. Serafino; F. Barreca; F. Caridi (pp. 2298-2302).

Keywords: Pulsed laser ablation; Reflection electron energy loss spectroscopy; Zinc oxide; Thin films

Circular and rectangular via holes formed in SiC via using ArF based UV excimer laser by L. Liu; C.Y. Chang; Wenhsing Wu; S.J. Pearton; F. Ren (pp. 2303-2307).

Circular via holes with diameters of 10, 25, 50 and 70μm and rectangular via holes with dimensions of 10μm×100μm, 20μm×100μm and 30μm×100μm and drilled depths between 105 and 110μm were formed in 300μm thick bulk 4H-SiC substrates by Ar/F₂ based UV laser drilling ( λ=193nm) with a pulse width of ∼30ns and a pulse frequency of 100Hz. The drilling rate was linearly proportional to the fluence of the laser, however, the rate decreased for the larger via holes. The laser drilling produces much higher etch rates (229–870μm/min) than conventional dry etching (0.2–1.3μm/min) and the via entry can be tapered to facilitate subsequent metallization.

Keywords: Laser drill; Via holes; SiC; Excimer laser

Circular and rectangular via holes formed in SiC via using ArF based UV excimer laser by L. Liu; C.Y. Chang; Wenhsing Wu; S.J. Pearton; F. Ren (pp. 2303-2307).

Keywords: Laser drill; Via holes; SiC; Excimer laser

Superhydrophobicity of silica nanoparticles modified with polystyrene by X.L. Sun; Z.P. Fan; L.D. Zhang; L. Wang; Z.J. Wei; X.Q. Wang; W.L. Liu (pp. 2308-2312).

Display Omitted▶ Polystyrene/silica nanoparticles were prepared by radical polymerization of silica nanoparticles possessing vinyl groups and styrene with benzoyl peroxide. ▶ The superhydrophobic surface was fabricated by combining of the organic and inorganic materials. ▶ A modified CB relation was used to confirm the superhydrophobicity of the resultant films.Polystyrene/silica nanoparticles were prepared by radical polymerization of silica nanoparticles possessing vinyl groups and styrene with benzoyl peroxide. The resulting vinyl silica nanoparticles, polystyrene/silica nanoparticles were characterized by means of Fourier transformation infrared spectroscopy, scanning electron microscopy and UV–vis absorption spectroscopy. The results indicated that polystyrene had been successfully grafted onto vinyl silica nanoparticles via covalent bond. The morphological structure of polystyrene/silica nanoparticles film, investigated by scanning electron microscopy, showed a characteristic rough structure. Surface wetting properties of the polystyrene/silica nanoparticles film were evaluated by measuring water contact angle and the sliding angle using a contact angle goniometer, which were measured to be 159° and 2°, respectively. The excellent superhydrophobic property enlarges potential applications of the superhydrophobic surfaces.

Keywords: Superhydrophobic surface; CB relation; Contact angle; Polystyrene; Silica nanoparticles

Superhydrophobicity of silica nanoparticles modified with polystyrene by X.L. Sun; Z.P. Fan; L.D. Zhang; L. Wang; Z.J. Wei; X.Q. Wang; W.L. Liu (pp. 2308-2312).

Keywords: Superhydrophobic surface; CB relation; Contact angle; Polystyrene; Silica nanoparticles

Intense laser effects on nonlinear optical absorption and optical rectification in single quantum wells under applied electric and magnetic field by C.A. Duque; E. Kasapoglu; S. Şakiroglu; H. Sari; I. Sökmen (pp. 2313-2319).

In this work the effects of intense laser on the electron-related nonlinear optical absorption and nonlinear optical rectification in GaAs–Ga1−_xAl_xAs quantum wells are studied under, applied electric and magnetic field. The electric field is applied along the growth direction of the quantum well whereas the magnetic field has been considered to be in-plane. The calculations were performed within the density matrix formalism with the use of the effective mass and parabolic band approximations. The intense laser effects are included through the Floquet method, by modifying the confining potential associated to the heterostructure. Results are presented for the nonlinear optical absorption, the nonlinear optical rectification and the resonant peak of these two optical processes. Several configurations of the dimensions of the quantum well, the applied electric and magnetic fields, and the incident intense laser radiation have been considered. The outcome of the calculation suggests that the nonlinear optical absorption and optical rectification are non-monotonic functions of the dimensions of the heterostructure and of the external perturbations considered in this work.

Keywords: Quantum well; Nonlinear optics; Intense laser field

Surface properties of polypropylene/organoclay nanocomposites by Maryam Ataeefard; Siamak Moradian (pp. 2320-2326).

Influence of nanoclay amount on surface properties of the nanocomposites was investigated using Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), contact angle measurement, scanning electron microscopy (SEM) and transmission spectroscopy (TS). Polypropylene based nanocomposites containing various loads of nanoclay were prepared by melt compounding. X-ray diffraction (XRD) characterized the dispersion of nanoclay in polymer matrix. AFM and SEM studies have shown increase in surface roughness by raising the amount of nanoclay. Contact angle measurements of the resultant nanocomposites have also shown improvement in wettability related to disperse part of surface tension. POM images illustrated an increase in the number of spherulite simultaneously with a decrease in their size; this result was also supported by differential scanning calorimetry (DSC).

Keywords: Key words; Nanocomposite; Polypropylene; Montmorillonite; Nanoclay; Contact angle; Surface characterization

Surface properties of polypropylene/organoclay nanocomposites by Maryam Ataeefard; Siamak Moradian (pp. 2320-2326).

Keywords: Key words; Nanocomposite; Polypropylene; Montmorillonite; Nanoclay; Contact angle; Surface characterization

Studies of photo-induced charge transfer properties of ZnWO₄ photocatalyst by Dongqing He; Xiaoru Zhang; Tengfeng Xie; Jiali Zhai; Haiyan Li; Liping Chen; Linlin Peng; Yu Zhang; Tengfei Jiang (pp. 2327-2331).

▶ ZnWO₄ nanorods are supposed to take on the character of n-type semiconductor.▶ Surface states affect the increasing SPV response intensity and the red shift. ▶ Surface states make charge transport and recombination retardation.▶ ZnWO₄ (413K) possesses the most abundant surface states and the best photocatalytic activity.Different sizes of ZnWO₄ photocatalysts were synthesized by a hydrothermal method. The as-prepared sample shows highly efficient photocatalytic activity for the degradation of RhB under UV irradiation, which significantly vary with the increase of the hydrothermal temperatures. Surface photovoltage spectrum (SPS), field-induced surface photovoltage spectrum (FI-SPS) and surface photovoltage transient (TPV) techniques are used to investigate the detailed photoinduced charge transfer behavior. Results indicate that the ZnWO₄ synthesized at 413K possess the largest BET surface area and the abundant donor surface states which are assumed to inhibit the recombination of the photogenerated electron–hole pairs, and thus a significant enhancement in the reaction rate is observed.

Keywords: ZnWO; ₄; nanorods; Surface states; Surface photovoltage; Transient photovoltage

Determination of residual stresses within plasma spray coating using Moiré interferometry method by Jiang Yi; Xu Bin-shi; Wang Hai-dou; Liu Ming; Lu Yao-hui (pp. 2332-2336).

In this paper, residual stresses of the Ni–Cr–B–Si coatings prepared by supersonic plasma spray processing were measured by moiré interferometry and X-ray diffraction method. Moiré interferometry method was used in measuring the distribution of residual stresses of the Ni–Cr–B–Si coatings alongside the specimen thickness direction, then the distribution of residual stresses both in the substrate and the coating was also analyzed. Experimental results showed that residual stresses in the coating and the substrate are tensile and compressive separately; residual stresses of the coating are diminished with the increase of the distance from the coating surface and almost zero at the coating–substrate interface; the maximum of compressive residual stresses of the substrate are present to the vicinity of the coating–substrate interface. It could be concluded that residual stresses in the specimen would result from the dismatch of thermophysical properties between the coating and substrate during the spray process, and the distribution of residual stresses of the substrate would be influenced by the sandblasting prior to spraying.

Keywords: Coating; Residual stress; Moiré interferometry; X-ray analysis

Determination of residual stresses within plasma spray coating using Moiré interferometry method by Jiang Yi; Xu Bin-shi; Wang Hai-dou; Liu Ming; Lu Yao-hui (pp. 2332-2336).

Keywords: Coating; Residual stress; Moiré interferometry; X-ray analysis

Fabrication and characterization of Mg-doped pencil-shaped ZnO microprisms by Junlin Li; Huizhao Zhuang; Jie Wang; Peng Xu (pp. 2337-2340).

Two types of novel Mg-doped pencil-shaped ZnO microprisms had been successfully synthesized on Mg(NO₃)₂-coated Si (111) substrates by thermal chemical vapor deposition method. The as-prepared ZnO prisms were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), field-emission transmission electron microscope (FETEM), selected area electron diffraction (SAED), and photoluminescence (PL) spectroscopy. The straight microprisms are made up of hexagonal pyramids tips and hexagonal prisms bodies. Both of the structures are perfect single crystal and have grown along the [0001] direction preferentially. Photoluminescence reveals a red-shift at around 387nm which is induced by Mg doping and a green light emission peak at around 511nm. The pencil-shaped ZnO microstructure can provide an improvement in novel ultraviolet light-emitting devices. In addition, the growth mechanism of the special ZnO microprisms is discussed briefly.

Keywords: ZnO material; Mg-doped; Microprisms; Photoluminescence

Fabrication and characterization of Mg-doped pencil-shaped ZnO microprisms by Junlin Li; Huizhao Zhuang; Jie Wang; Peng Xu (pp. 2337-2340).

Keywords: ZnO material; Mg-doped; Microprisms; Photoluminescence

Low temperature synthesis wide optical band gap Al and (Al, Na) co-doped ZnO thin films by Tao Wang; Yanmei Liu; Qingqing Fang; Mingzai Wu; Xia Sun; Fei Lu (pp. 2341-2345).

Al-doped ZnO (AZO) and (Al, Na) co-doped ZnO (ANZO) thin films were prepared via sol–gel technique with an annealing process at temperatures between 450 and 550°C for 60min in air ambient, and their structural and optical properties have been investigated. The deposited films exhibited hexagonal zinc oxide structure except annealing at 450°C. For the 500°C-annealed samples, the surface morphology was analyzed via scanning electron microscopy, Photoluminescence (PL) of different Na content ANZO thin films showed that there were very obvious violet and blue emission bands between 400 and 500nm, and intensity of which were enhanced with Na content increasing. Transparency of the films was improved along with increasing Na content. The result of UV indicated the absorb bands appeared obviously red shift with Na doping into ZnO, the optical gaps of all films far beyond 3.37eV of pure ZnO, and gradually decreased with Na content increasing, this is very virtual for improving photoelectricity performance of transparent conduct oxide (TCO) film. The possible origins responsible for structure and optical properties also had been discussed.

Keywords: (Al, Na) co-doped ZnO; Sol–gel spin coating; Wide optical band gap; Red shift

Low temperature synthesis wide optical band gap Al and (Al, Na) co-doped ZnO thin films by Tao Wang; Yanmei Liu; Qingqing Fang; Mingzai Wu; Xia Sun; Fei Lu (pp. 2341-2345).

Keywords: (Al, Na) co-doped ZnO; Sol–gel spin coating; Wide optical band gap; Red shift

XPS study of protein adsorption onto nanocrystalline aluminosilicate microparticles by E. Vanea; V. Simon (pp. 2346-2352).

X-ray photoelectron spectroscopy (XPS) was used to study the interaction of two different sized proteins, bovine serum albumin (BSA) and fibrinogen, with an aluminosilicate system containing yttrium and iron that is a potential biomaterial. Serum albumin and fibrinogen are two major plasma proteins and the most relevant proteins adsorbed on the surface of biomaterials in blood contact.The aluminosilicate samples were incubated for several exposure times, up to 24h, in simulated body fluid enriched with BSA, and in buffered fibrinogen solution. Time dependence of proteins adsorption onto surface of the investigated samples is reflected by the evolution of the new N 1s photoelectron peak and by the modification of C 1s core-level spectra recorded from the samples immersed in protein solution.

Keywords: Aluminosilicates; Nanostructured microparticles; Protein adsorption; XPS

XPS study of protein adsorption onto nanocrystalline aluminosilicate microparticles by E. Vanea; V. Simon (pp. 2346-2352).

Keywords: Aluminosilicates; Nanostructured microparticles; Protein adsorption; XPS

Hot embossing of PTFE: Towards superhydrophobic surfaces by D. Jucius; V. Grigaliūnas; M. Mikolajūnas; A. Guobienė; V. Kopustinskas; A. Gudonytė; P. Narmontas (pp. 2353-2360).

▶ PTFE was hot embossed above the glass transition temperature. ▶ Impact of temperature, pressure and time on pattern transfer was tested. ▶ Water repelency was improved up to the superhydrophobic region.Three types of reusable stamps with features in the form of 2D arrays of pits having lateral dimensions in the range of 2–80μm and heights of 1.5–15μm were successfully employed for the hot embossing of PTFE at temperatures up to 50°C above the glass transition temperature of PTFE amorphous phase. Due to the softening of PTFE at the temperatures used in this study, we were able to decrease imprint pressure significantly when comparing with the imprint conditions reported by other authors. Impact of the imprint temperature, pressure and time on the fidelity of pattern transfer as well as on water repellency was tested. The best results of embossing were achieved by applying pressure of 10kg/cm² for 2min at 170°C. In this case, flattening of a natural PTFE roughness and pretty accurate deep replicas of the stamp patterns were observable on the whole imprinted area. Improvement in water repellency was largest for the samples imprinted by Ni stamp patterned with a 2D array of 2μm square pits spaced by the same dimension and having a depth of 1.5μm. Cassie–Baxter wetting regime was observed for the deepest imprints with water contact angles up to the superhydrophobic limit.

Keywords: Polytetrafluoroethylene; Hot embossing; Hydrophobicity; Contact angle

Hot embossing of PTFE: Towards superhydrophobic surfaces by D. Jucius; V. Grigaliūnas; M. Mikolajūnas; A. Guobienė; V. Kopustinskas; A. Gudonytė; P. Narmontas (pp. 2353-2360).

Keywords: Polytetrafluoroethylene; Hot embossing; Hydrophobicity; Contact angle

Adsorption and photocatalytic degradation of methylene blue on Zn1−_xCu_xS nanoparticles prepared by a simple green method by S. Naghiloo; A. Habibi-Yangjeh; M. Behboudnia (pp. 2361-2366).

Nanoparticles of Zn1−_xCu_xS with various dopant contents (0≤ x≤0.15) were prepared in water by refluxing for 90min at about 95°C. Powder X-ray diffraction (XRD) patterns of the nanoparticles demonstrate that loading of Cu²⁺ ions does not change the crystal structure of ZnS. Scanning electron microscopy (SEM) images demonstrate that size of the nanoparticles decreases with increasing Cu²⁺ ions. UV–Vis diffuse reflectance spectra (DRS) of the nanoparticles show significant absorption in visible light region. Adsorption capacity of the nanoparticles for methylene blue (MB) increases with mole fraction of copper ions. Photocatalytic activity of the nanoparticles toward photodegradation of MB was evaluated under visible light irradiation. The results indicate that Zn_0.85Cu_0.15S nanoparticles exhibit highest photocatalytic activity among the prepared samples. Moreover, effects of refluxing time applied for preparation of the nanoparticles and calcination temperature were investigated.

Keywords: PACS; 61.46.Df; 81.05.Dz; 81.07.Bc; 81.20.FwSolid solution; Zn; 1−; _x; Cu; _x; S; Nanoparticles; Photocatalysis; Adsorption

Adsorption and photocatalytic degradation of methylene blue on Zn1−_xCu_xS nanoparticles prepared by a simple green method by S. Naghiloo; A. Habibi-Yangjeh; M. Behboudnia (pp. 2361-2366).

Keywords: PACS; 61.46.Df; 81.05.Dz; 81.07.Bc; 81.20.FwSolid solution; Zn; 1−; _x; Cu; _x; S; Nanoparticles; Photocatalysis; Adsorption

One-step, template-free route to silver porous hollow spheres and their optical property by Rongbo Zheng; Xuelian Guo; Hui Fu (pp. 2367-2370).

Display OmittedSilver porous hollow spheres (SPHS) were obtained via ultrasonic spray pyrolysis of aqueous solutions containing AgNO₃ and glucose. The pores with size in the range of tens to hundreds nanometers were randomly distributed in the shells of silver hollow spheres. SPHS exhibited a wide Vis–NIR adsorption in the range of 400–1100nm.Silver porous hollow spheres (SPHS) were fabricated via ultrasonic spray pyrolysis of aqueous solutions containing AgNO₃ and glucose. In the hot spherical liquid droplets, glucose, as reducing agent, reacted with Ag⁺ to form Ag nanoparticles, which subsequently moved to the periphery of the hot liquid droplets to form Ag nanoparticles–glucose hybrid shell. With the temperature further increased, aforementioned Ag nanoparticles melted to form Ag skeleton decorated with unreacted glucose, which converted to SPHS via dissolving unreacted glucose in water. Due to their porous hollow structures, SPHS exhibited a wide Vis–NIR adsorption in the range of 400–1100nm.

Keywords: Silver; Porous hollow spheres; Optical

One-step, template-free route to silver porous hollow spheres and their optical property by Rongbo Zheng; Xuelian Guo; Hui Fu (pp. 2367-2370).

Keywords: Silver; Porous hollow spheres; Optical

SiO₂ stabilized Pt/C cathode catalyst for proton exchange membrane fuel cells by Tong Zhu; Chunyu Du; Chuntao Liu; Geping Yin; Pengfei Shi (pp. 2371-2376).

This paper describes the preparation of SiO₂ stabilized Pt/C catalyst (SiO₂/Pt/C) by the hydrolysis of alkoxysilane, and examines the possibility that the SiO₂/Pt/C is used as a durable cathode catalyst for proton exchange membrane fuel cells (PEMFCs). TEM and XRD results revealed that the hydrolysis of alkoxysilane did not significantly change the morphology and crystalline structure of Pt particles. The SiO₂/Pt/C catalyst exhibited higher durability than the Pt/C one, due to the facts that the silica layers covered were beneficial for reducing the Pt aggregation and dissolution as well as increasing the corrosion resistance of supports, although the benefit of silica covering was lower than the case of Pt/CNT catalyst. Also, it was observed that the activity of the SiO₂/Pt/C catalyst for the oxygen reduction reaction was somewhat reduced compared to the Pt/C one after the silica covering. This reduction was partially due to the low oxygen kinetics as revealed by the rotating-disk-electrode measurement. Silica covering by hydrolysis of only 3-aminopropyl trimethoxysilane is able to achieve a good balance between the durability and activity, leading to SiO₂/Pt/C as a promising cathode catalyst for PEMFCs.

Keywords: PEMFC; Cathode catalyst; Durability; Oxygen reduction reaction; Silica covering

SiO₂ stabilized Pt/C cathode catalyst for proton exchange membrane fuel cells by Tong Zhu; Chunyu Du; Chuntao Liu; Geping Yin; Pengfei Shi (pp. 2371-2376).

Keywords: PEMFC; Cathode catalyst; Durability; Oxygen reduction reaction; Silica covering

Wettability and sizing property improvement of raw cotton yarns treated with He/O₂ atmospheric pressure plasma jet by Shiyuan Sun; Jie Sun; Lan Yao; Yiping Qiu (pp. 2377-2382).

▶ The plasma treatment decrease water absorption time of cotton yarn from a few hours to 0.8s. ▶ The obtained high wettability had no apparent aging within 24h. ▶ The size adhesion test showed a nearly doubled adhesion of the sizing to the yarns.Raw cotton fiber is water repellent due to the existence of the water repellent cuticle layer. This study is designed to systematically investigate how He/O₂ atmospheric pressure plasma jet (APPJ) treatments influence the wettability and the sizing property of cotton yarns. Water absorption time and adhesion of the sizing agent to the cotton roving are used to evaluate the improvement of wettability and sizing property of the yarn respectively. The water absorption time decreases with the increase of the treatment time and the oxygen flow rate, and the decrease of the jet to substrate distance (JTSD). An optimal water absorption time of 0.8s is obtained with a treatment time of 20s, JTSD of 1mm and O₂ flow rate of 0.2L/min. Scanning electron microscopy (SEM) shows that the etching effect increases with the decrease of the JTSD and X-ray photoelectron spectroscopy (XPS) presents increased oxygen contents after the plasma treatments. An increase of O–CO bonds while a decrease of C–OH/C–O–C bonds are observed when the JTSD is set at 2mm. However, a remarkable increase of both C–OH/C–O–C and O–CO bonds are achieved when the JTSD is 1mm. The roving impregnation test results show a nearly doubled adhesion of sizing and a slightly improved breaking elongation, indicating that the plasma treatment does effectively enhance the bonding strength between the fiber and the sizing.

Keywords: Key words; Atmospheric pressure plasma; Cotton; Surface wettability; XPS; Water contact angle

Wettability and sizing property improvement of raw cotton yarns treated with He/O₂ atmospheric pressure plasma jet by Shiyuan Sun; Jie Sun; Lan Yao; Yiping Qiu (pp. 2377-2382).

Keywords: Key words; Atmospheric pressure plasma; Cotton; Surface wettability; XPS; Water contact angle

Microwave absorption properties of rod-shaped Co–Ni–P shells prepared by metallizing Bacillus by Jianhua Liu; Xiaoliang Zhang; Songmei Li; Mei Yu (pp. 2383-2386).

The rod-shaped Co–Ni–P shells were prepared by metalling Bacillus. The microstructures and composition of the shells were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive analysis (EDS). The electromagnetic parameters were measured by the coaxial line method in the frequency of 2–18GHz. It was found that the Bacillus were successfully coated with Co–Ni–P, and the inner structure of the shells are hollow in structure. The shells exhibit excellent microwave absorption properties in 5–17GHz frequency. The microwave reflection loss is above −10dB in 5.38–16.6GHz frequency. The maximum microwave reflection loss reaches −35.83dB at 9.12GHz for samples thickness 2.4mm, and the widest bandwidth for microwave reflection loss above −10dB is about ∼5.32GHz for samples thickness 2.0mm. These results confirm the feasibility of applying Bacillus as biotemplates for fabrication of the metallic shells as lightweight microwave absorption materials are very promising for applications.

Keywords: Bacillus; Biotemplates; Metallic shells; Microwave absorption

Microwave absorption properties of rod-shaped Co–Ni–P shells prepared by metallizing Bacillus by Jianhua Liu; Xiaoliang Zhang; Songmei Li; Mei Yu (pp. 2383-2386).

Keywords: Bacillus; Biotemplates; Metallic shells; Microwave absorption

Effects of different binders on microstructure and phase composition of hydroxyapatite Nd–YAG laser clad coatings by C.S. Chien; T.F. Hong; T.J. Han; T.Y. Kuo; T.Y. Liao (pp. 2387-2393).

The laser clad coating technique can help to produce metallurgical bonding with high bonding strength between the coating layer and the substrate, which has been gradually applied for hydroxyapatite (HA) coating on metallic substrates. In this study, HA powder is mixed with two different binders, namely water glass (WG) and polyvinyl alcohol (PVA), respectively, and is then clad on Ti–6Al–4V substrates using an Nd:YAG laser system under various processing conditions. The microstructure, chemical composition and hardness of the coating layer and transition layer of the various samples are then systematically explored. The experimental results show that the coating layers of the various samples all contain both cellular dendrites and rod-like piled structures, while the transition layers contain only cellular dendrites. For all samples, the coating layer consists mostly of CaTiO₃, Ca₂P₂O₇, CaO and HA phases, whereas the transition layer contains primarily CaTiO₃, Ca₂P₂O₇, Ti₃P, Ti and HA phases. In addition, the transition layer of the WG samples also contains SiO₂ and Si₂Ti phases. In all of the specimens, the transition layer has a higher average hardness than the substrate or coating layer. Moreover, the transition layer in the WG sample is harder than that in the PVA sample.

Keywords: Hydroxyapatite (HA); Nd:YAG laser cladding; Polyvinyl alcohol (PVA); Water glass (WG); Ti–6Al–4V

Effects of different binders on microstructure and phase composition of hydroxyapatite Nd–YAG laser clad coatings by C.S. Chien; T.F. Hong; T.J. Han; T.Y. Kuo; T.Y. Liao (pp. 2387-2393).

Keywords: Hydroxyapatite (HA); Nd:YAG laser cladding; Polyvinyl alcohol (PVA); Water glass (WG); Ti–6Al–4V

Characterization of the metallic phase in nanocrystalline ZnAl₂O₄-supported Pt catalysts by Wiktoria Walerczyk; Mirosław Zawadzki; Janina Okal (pp. 2394-2400).

▶ Studied ZnAl₂O₄ supports have high capacity to achieve high dispersion of Pt phase. ▶ H₂ and O₂ chemisorption is useful to characterization of the low-loaded Pt/ZnAl₂O₄. ▶ The H₂–O₂ titration technique is limited to high-loaded Pt/ZnAl₂O₄ catalysts.In this study several complementary methods as XRD, HRTEM, O₂ and H₂ adsorption, as well as H₂–O₂ titration were used for characterization of the metallic phase in 0.5–3.0wt.% Pt/ZnAl₂O₄ catalysts. Three nanocrystalline ZnAl₂O₄ spinels used as a supports were prepared by the solvothermal and co-precipitation method. It was found that irrespective of the preparation method they form very good support materials with a high capacity to achieve high platinum dispersion. O₂ and H₂ chemisorption data showed metal dispersion up to 90% and good correspondence with HRTEM results was observed. The H₂–O₂ titration method may be applied for determination of Pt dispersion only in the high-loaded Pt/ZnAl₂O₄ catalysts. The catalytic performances of Pt supported on the prepared spinels were evaluated in the propane total oxidation reaction.

Keywords: Platinum dispersion; Pt/ZnAl; ₂; O; ₄; catalysts; H; ₂; and O; ₂; chemisorption; H; ₂; –O; ₂; titration

Characterization of the metallic phase in nanocrystalline ZnAl₂O₄-supported Pt catalysts by Wiktoria Walerczyk; Mirosław Zawadzki; Janina Okal (pp. 2394-2400).

Keywords: Platinum dispersion; Pt/ZnAl; ₂; O; ₄; catalysts; H; ₂; and O; ₂; chemisorption; H; ₂; –O; ₂; titration

The influence of treatment duration on multi-walled carbon nanotubes functionalized by H₂SO₄/HNO₃ oxidation by Yu-Chun Chiang; Wei-Hsiang Lin; Yung-Chia Chang (pp. 2401-2410).

▶ Decrease in crystallinity was from widening of XRD peak, followed by shifting towards lower angles. ▶ A defect peak in XPS C1s spectra was helpful for detecting the generation of defect sites. ▶ The oxidation mechanism of MWCNTs in mild H₂SO₄/HNO₃ mixture was proposed.Variation in the nature of multi-walled carbon nanotubes (MWCNTs) subjected to different degrees of oxidation was investigated. The microstructure was determined by high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) methods, and the surface chemistry was evaluated in terms of the functional groups determined by X-ray photoelectron spectroscopy (XPS) and thermal analysis–mass spectroscopy (TA–MS). In addition, TGA was used to indicate the thermal stability of the nanotubes. Results demonstrate that the graphitic structure of nanotubes oxidized with a mild mixture of H₂SO₄/HNO₃ was preserved. Decrease in the degree of crystallinity started with widening of the C(002) XRD diffraction peak, followed by this peak shifting towards lower angles. The oxygen content increased with increasing treatment time. A defect peak incorporated in deconvolution of XPS C1s spectra was helpful for detecting the generation of defect sites. The predominant surface functionalities of the nanotubes have been changed from basic to acidic groups after treatment for one day. The samples oxidized for two days had the most abundant surface –COOH and the highest oxidation resistance. The oxidation mechanism of MWCNTs in mild H₂SO₄/HNO₃ mixture was proposed, which was a successive and iterative process, including the initial attack on active sites, and next the hexagon electrophilic attack generating new defects and introducing more oxygen, and then the tubes becoming thinner and shorter.

Keywords: Carbon nanotubes; Acid oxidation; X-ray photoelectron spectroscopy; Thermal analysis–mass spectrometry; Oxidation mechanism

The influence of treatment duration on multi-walled carbon nanotubes functionalized by H₂SO₄/HNO₃ oxidation by Yu-Chun Chiang; Wei-Hsiang Lin; Yung-Chia Chang (pp. 2401-2410).

Keywords: Carbon nanotubes; Acid oxidation; X-ray photoelectron spectroscopy; Thermal analysis–mass spectrometry; Oxidation mechanism

Corrigendum to “Deposition of Ag nanostructures on TiO₂ thin films by RF magnetron sputtering” [Appl. Surf. Sci. 256 (2010) 7096–7101] by J. Zuo (pp. 2411-2411).

Erratum to “GaAs surface passivation by plasma-enhanced atomic-layer-deposited aluminum nitride” [Appl. Surf. Sci. 256 (2010) 7434–7437] by M. Bosund; P. Mattila; A. Aierken; T. Hakkarainen; H. Koskenvaara; M. Sopanen; V.-M. Airaksinen; H. Lipsanen (pp. 2412-2412).

Erratum to “Electrical conditioning of diamond-like carbon films for the formation of coated field emission cathodes” [Appl. Surf. Sci. 257 (2010) 388–392] by M. Semenenko; G. Okrepka; O. Yilmazoglu; H.L. Hartnagel; D. Pavlidis (pp. 2413-2413).

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Applied Surface Science (v.257, #6)