Effect Of Surface Microstructure Research Articles

Effect of surface microstructure and wettability on plasma protein adsorption to ZnO thin films prepared at different RF powers

In this paper, the adsorption behavior of plasma proteins on the surface of ZnO thin films prepared by radio frequency (RF) sputtering under different sputtering powers was studied. The microstructures and surface properties of the ZnO thin films were investigated by x-ray diffraction (XRD), scanning electron microscopy (SEM), UV–visible optical absorption spectroscopy and contact angle techniques. The results show that the ZnO thin films have better orientation of the (0 0 2) peak with increasing RF power, especially at around 160 W, and the optical band gap of the ZnO films varies from 3.2 to 3.4 eV. The contact angle test carried out by the sessile drop technique denoted a hydrophobic surface of the ZnO films, and the surface energy and adhesive work of the ZnO thin films decreased with increasing sputtering power. The amounts of human fibrinogen (HFG) and human serum albumin (HSA) adsorbing on the ZnO films and reference samples were determined by using enzyme-linked immunosorbent assay (ELISA). The results show that fewer plasma proteins and a smaller HFG/HSA ratio adsorb on the ZnO thin films' surface.

Effect of surface microstructures on photo-induced hydrophilicity of NaNbO3 thin films by sol–gel process

Abstract The photo-induced hydrophilicity of sodium niobate (NaNbO 3 ) films prepared by the sol–gel method was investigated. Although the films annealed at by 700 and 900 °C exhibited a more heterogeneous microstructure (average grain size: 30–40 nm, 50–80 nm, respectively) than that for films annealed at 500 °C (15–20 nm), the crystallinity and the band gaps of the films were all approximately the same. The films exhibited photo-induced hydrophilicity under UV-B light irradiation. The photo-induced hydrophilic response of the film annealed at 500 °C was higher than those of the films annealed at 700 and 900 °C. It is proposed that the photo-induced hydrophilicity of NaNbO 3 films is affected by the surface microstructure.

Evaluation of boronate-containing polymer brushes and gels as substrates for carbohydrate-mediated adhesion and cultivation of animal cells

Boronate-containing thin polyacrylamide gels (B-Gel), polymer brushes (B-Brush) and chemisorbed organosilane layers (B-COSL) were prepared on the surface of glass slides and studied as substrates for carbohydrate-mediated cell adhesion. B-COSL- and B-Brush-modified glass samples exhibited multiple submicron structures densely and irregularly distributed on the glass surface, as found by scanning electron microscopy and atomic force microscopy. B-Gel was ca. 0.1 mm thick and contained pores with effective size of 1–2 μm in the middle and of 5–20 μm on the edges of the gel sample as found by confocal laser scanning microscopy. Evidence for the presence of phenylboronic acid in the samples was given by time-of-flight secondary ion mass-spectrometry (ToF SIMS), contact angle measurements performed in the presence of fructose, and staining with Alizarin Red S dye capable of formation specific, fluorescent complexes with boronic acids. A comparative study of adhesion and cultivation of animal cells on the above substrates was carried out using murine hybridoma M2139 cell line as a model. M2139 cells adhered to the substrates in the culture medium without glucose or sodium pyruvate at pH 8.0, and then were cultivated in the same medium at pH 7.2 for 4 days. It was found that the substrates of B-Brush type were superior both regarding cell adhesion and viability of the adhered cells, among the substrates studied. MTT assay confirmed proliferation of M2139 cells on B-Brush substrates. Some cell adhesion was also registered in the macropores of B-Gel substrate. The effects of surface microstructure of the boronate-containing polymers on cell adhesion are discussed. Transparent glass substrates grafted with boronate-containing copolymers offer good prospects for cell adhesion studies and development of cell-based assays.

Effect of surface microstructures on the separation efficiency of neurotransmitters on a direct-printed capillary electrophoresis microchip

The effect of surface microstructures of microchannels on the separation efficiency in microchip electrophoresis has been studied. In order to understand the influence of the surface microstructures on the microchip electrophoresis performance, a thermostatic system was designed and fabricated for precisely control of the chip temperature since the surrounding temperature causes a significant effect on the separation efficiency. The periodically ordered microstructures (dams) of different sizes were fabricated on the microchannels by a simple printing process using different gray levels of the vector graphic software. And the influence of dam sizes in microchannels on the separation efficiency was evaluated by using the number of theoretical plates ( N) and the relative resolution (Rs’). Analyzing the variations of mixing elements caused by the periodically ordered dams in the separate channel and elution time, we found that with small dam size fabricated at low gray level of ca. 30%, the resolution of dopamine and epinephrine increased slightly, while it decreased obviously with larger dam sizes especially fabricated at gray level of 50%.

Effects of surface microstructure of hydroxyapatite on protein adsorption and biological performance of osteoblasts

The aim of this study was to investigate the effect of surface microstructure on the serum protein adsorption and the biological performance of osteoblasts cultured in vitro, when seeded onto the surface of ceramics with different grain size: conventional HA, micron-sized HA and nano-sized HA. Sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to comparatively analyze the protein adsorption solution. The content of alkaline phosphatase (ALP) was determined, and then by using wash way method, the adhesion ability was tested. XPS tests indicated that the content of N on the surface was significant different between the three groups ( P < 0.05). SDS-PAGE analysis indicated that all the materials in these three groups could adsorb a large amount albumin, while the material in the nHA group adsorbed more albumin than the other groups. There were significant differences among them on the levels of osteoblast proliferation and adhesion in vitro. The biocompatibility of nHA is the best and of conventional HA is the worst.

Cr 2O 3-activated ZnO thick film resistors for ammonia gas sensing operable at room temperature

Pure ZnO thick films, prepared by screen-printing technique, were almost insensitive to NH 3. Pure ZnO thick films were surface activated with Cr 3+ by dipping them into an aqueous solution (0.01 M) of chromium trioxide CrO 3 for different intervals of time and fired at 500 °C for 24 h. The CrO 3 is known to be unstable above 197 °C and transforms into Cr 2O 3 upon firing above 197 °C. The grains of Cr 2O 3 would disperse around the grains of ZnO base material. The Cr 3+-activated ZnO films dipped for 5 min were observed to be sensitive and highly selective to 300 ppm of NH 3 gas at room temperature. The effects of surface microstructure and Cr 3+ concentrations on the sensitivity, selectivity, response and recovery of the sensor in the presence of NH 3 and other gases were studied and discussed. The better performance could be attributed to an optimum number of surface misfits in terms of Cr 2O 3 on the ZnO films.

Effect of Surface Microstructure of Titanium Sheet on the Photocatalytic Activity of Its Oxide Film

Titanium oxide film was formed by thermal oxidation directly on titanium sheet. Pretreatments on titanium sheet were carried out using annealing in Argon at 873 K, 973 K and 1073 K for 5 min, 30 min and 100 min, respectively. Photocatalytic performance of titanium oxide film was examined by measuring the degradation of methylene blue. The crystallographic orientation distribution of titanium sheet was analyzed by SEM/EBSP technique whereas the crystalline structure of titanium oxide film was characterized by XRD. Development of recrystallization texture on titanium sheet gained during the annealing, in which stored energy was lowered, was proved to facilitate formation of the preferable oxide film with high photocatalytic property during oxidation. However, grain size of titanium sheet was found to be another important and effective factor since grain boundaries were testified to be the channels for the diffusion of oxygen in the thermal oxidation reaction. Grain coarsening of titanium sheet is probably a detriment to high photocatalytic activity of its oxide film.

Knowledge Discovery Applications in High-Throughput Polymer Characterization

AbstractThe use of combinatorial libraries for screening cell-material interactions presents a significant need for robust informatics methods capable of extracting knowledge from large, combinatorial datasets. We describe the development of local quantitative metrics based on distributions of other cells and microstructures about each individual cell. The local metrics are shown to be superior to global, summary statistics in detecting sensitive effects of surface microstructure on proliferation of MC3T3-E1 osteoblasts.

Effect of surface microstructure on the photoinduced hydrophilicity of porous TiO2 thin films

The relationship between photoinduced hydrophilicity and surface microstructure of porous TiO2 thin films has been investigated. Porous TiO2 thin films on soda-lime glass were prepared by the sol–gel method from alkoxide solutions containing polyethylene glycol (PEG). These materials were characterised by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and UV-Vis transmittance measurements. The larger the amount of PEG used in preparing the thin films, the larger was the pore size produced from the thermal decomposition of PEG. This generated also a relatively rough thin film surface with a strong affinity for hydroxyl groups. This study proves that suitable surface microstructures can enhance the photoinduced super-hydrophilic properties of porous TiO2 thin films and hinder the conversion from a hydrophilic to a hydrophobic state. Among the porous TiO2 thin films tested, the one with a PEG to TiO2 mass ratio of 12.5% exhibited the best photoinduced super-hydrophilic property and the slowest conversion rate from the hydrophilic to a hydrophobic state.

Effect of surface microstructure on the super-hydrophilic property of the sol-gel derived porous TiO2 thin films

Effect of surface microstructure on the super-hydrophilic property of the sol-gel derived porous TiO2 thin films

Capillary Condensation and Melting/Freezing Transitions for Methane in Slit Coal Pores

Grand canonical Monte Carlo method has been applied to study the adsorption behavior of methane in slit coal micropores for pore widths from 1.5 to 4.5 nm at temperatures 111–300 K. The adsorbent surface is considered to be inhomogeneous with C, N, S, O and H atoms, as well as vacancies, taken into account. The effect of surface microstructure on mechanism of the pore filling and saturation pressure is found to be more pronounced at relatively low and moderate strength of the adsorption field. It is also shown that irregular impurities and defects at the adsorbent surface contribute to the lowering of the freezing temperature and can change qualitively its dependence on the pore width.

Effect of Surface Microstructure on the Temperature sensitivity of Burning Rate of Ammonium Perchlorate

Considering Vielle's law and the new thermodynamic model which the authors have developed recently, the true dependence of temperature sensitivity of burning rate (sigma(p)) of ammonium perchlorate (AP) on pressure is resolved and experimentally verified for pellet burning. The value of sigma(p) decreases with pressure steeply in regime I' (below 20 atm), but gently in regime I (above 20 atm). The sigma(p) value of powder AP has been determined and it is observed that sigma(p(powder)) > sigma(p(pellet)), which clearly suggests that sigma p is influenced by the surface temperature sensitive parameter (partial derivative T-s/partial derivative T-o)(p) and hence by the surface/subsurface microstructure. In powder burning, the buoyant lifting of the particles into the gas phase occurs, which constitutes the so-called 'free board region' (FBR) extending just above the true surface. Consequent to the decomposition of AP particles in FBR, the condensed phase heat release gets curtailed and sigma(p(powder)) becomes larger. A general relationship for sigma(p) in terms of density and surface temperature is suggested, which is applicable to both pellet and powder AP.

Influence of surface microstructure on the electric and spectroscopic characteristics of dielectric surface flashover

Spectroscopic investigations were performed on high purity polycrystalline alumina in vacuum to understand the effect of surface microstructure as altered by mechanical surface treatment, on the optical as well as the electrical characteristics of dielectric surface flashover. HV pulses were applied to unpolished samples as well as to samples subjected to mechanical polishing by using SiC (268 to 16 /spl mu/m) and diamond abrasives (15 to 0.25 /spl mu/m). The samples finished using diamond paste exhibited lower conditioned voltages and holdoff strength than those prepared with SiC abrasive finish. The spectrum of diamond-finished samples showed early development of molecular bands associated with the dielectric material. This behavior could be due to a larger density of defects developed on the surface during final polishing with diamond paste. There seems to be a correlation between the electrical performance of a sample, the polishing medium used for its surface finish, and the development of some of the spectral lines from flashover. The experimentally-observed phenomena in the studies point to different phases of surface conditioning, in which the dominating factors for the origin of surface flashover seem to depend on the surface state of the insulator.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Effects of Surface Microstructure and Chemical Compositions of Steels on Formation of Fe-Zn Compounds during Continuous Galvanizing

The effects of surface microstructure and chemical compositions on characteristics of Fe-Zn compounds which formed on continuously galvanized steel sheets have been investigated by using ultra low carbon and low carbon steels.From SEM observation, morphology of Fe-Zn compounds formed at interface between steel and plating layer were classified into three types; outburst structure, fine granular structure, and pillar-like structure.The amount of outburst structure increases with decreasing solute carbon content in steels. Phosphorus inhibited the formation of outburst structure when solute carbon was combined with a carbide forming element such as Nb or Ti.A comparison between distribution of Fe-Zn compounds and corresponding steel surface indicated that the outburst structure formed preferentially at grain boundaries exposed on the steel surface, whereas fine granular structure formed mainly at the interior of surface grains.

溶融亜鉛めつきの合金相形成におよぼす下地鋼板の組織と成分の影響

The effects of surface microstructure and chemical compositions of steels on characteristics of Fe-Zn intermetallic phases formed on continuously galvanized steel sheets have been investigated, using ultra low carbon and low carbon steels.From a SEM observation, the morphology of Fe-Zn IMP formed at interface between steel and plating layer were classified into three types ; outburst structure, fine granular structure, and pillar-like structure. The formation of the outburst structure was accelerated by decreasing solute carbon content in steels. Phosphorus inhibited this formation when solute carbon was combined with a carbide forming element such as Nb or Ti. The comparison between distribution of Fe-Zn IMP and corresponding steel surface indicated that the outburst structure was given priority to form at the grain boundaries exposed on the steel surface, whereas fine granular structure formed mainly at the surface grain interior.