Influence Of Surface Chemical Composition Research Articles

Influence of the Surface Chemical Composition Differences between Zirconia and Titanium with the Similar Surface Structure and Roughness on Bone Formation.

The osseointegration of zirconia (ZrO2) implants is still controversial. In this study, we aimed to make clear the influence of surface chemical composition, Ti or ZrO2, to osseointegration. First, a roughened Ti surface was prepared with a combination of large-grit sandblasting and acid treatment. Then, we applied molecular precursor solution containing Zr complex onto roughened Ti surface and can deposit thin ZrO2 film onto roughened Ti surface. We can change surface chemical composition from Ti to ZrO2 without changing the surface structure and roughness of roughened Ti. The tetragonal Zr was uniformly present on the ZrO2-coated Ti surface, and the surface of the ZrO2-coated Ti showed a higher apparent zeta potential than Ti. Ti and ZrO2-coated Ti rectangular plate implant was placed into the femur bone defect. After 2 and 4 weeks of implantation, histomorphometric observation revealed that the bone-to-implant contact ratio and the bone mass values for ZrO2-coated Ti implants inserted into the femur bone defects of the rats at 2 weeks were significantly higher than those for Ti implants (p < 0.05). It revealed that ZrO2 with a similar surface structure and roughness as that of roughened Ti promoted osteogenesis equivalent to or better than that of Ti in the early bone formation stage.

The influence of surface chemical composition of particles of boron carbide powders on their biological properties

The aim of this study was to explain differences in the biological behaviour of two boron carbide powders prepared by different synthesis methods. The commercial powder HD had a lower boron content in comparison to the synthesized powder SP. The analysis both powders surface confirmed the higher content of B-C bonds but the presence of heteroatomic B-C-O bonds indicating the oxide passivation of the surface of particles of only HD powder. On the other hand, the SP powder contains more boron in the volume as well as on the surface of particles. These differences facilitated the interaction between the carbide particles with the proteins in the culture medium. Proteins from the culture medium and active collagen peptides were more easily adsorbed to the surface of the synthesized powder particles, which was evidenced by new bands appearing in the spectrum. This translated into an increasing hydrophilicity of the synthesized boron carbide powder. The presence of proteins on the surface of the powder facilitated the cells adhesion of macrophages and fibroblasts. The synthesized boron carbide powder improved the macrophage functional status; the cells were characterized by high viability and low cytotoxicity as well as the correct morphology.

Quantifying the influence of surface chemical composition on surface energy during powder flow

In this study, the dominant intermolecular interactions at powder surfaces were investigated using inverse gas chromatography. Silica beads coated with molasses, corn starch, butter, or wheat gluten were used as model powders to emulate the interactions of surface components present in common food powders. The flow properties of the powders were analyzed using a rotational shear cell device at ambient conditions (25 °C and 40% relative humidity). A positive correlation (r = 0.72, p < 0.05) between the acid-base ratio (accounting for the ratio between the number of electron acceptor to electron donor surface sites) and the flow factor (flowability indicator, ffc at 1 kPa pre-shear stress) was observed for all the size ranges of surface-modified silica beads and industry-grade powders (modified corn starch and palm oil powders). The results depict the importance of acid-base surface components in understanding the mechanistic influence of pre-load molecular dynamics on the bulk flowability.

Fabrication of superhydrophobic surface with controlled adhesion by designing heterogeneous chemical composition

In this paper, a simple method for fabricating tunable adhesion superhydrophobic surface based on heterogeneous chemical composition was reported. By simply changing the ratio of HOOC(CH2)8COOH in the mixed modification solution, the slide angles (SA) of water droplet can be adjusted from extremely low (less than 10°) to very high (180°). Besides, the influence of surface chemical composition on the surface adhesion was also examined. Noticeably, the anti-corrosion performance of magnesium alloy was greatly improved after being modified. In addition, the tunable adhesion superhydrophobic magnesium alloy showed high hydrophobicity not only for pure water but also for corrosive liquids, such as acid, alkali, salt, cola, milk and coffee. Based on the great anti-corrosion performance and continuous adhesion, a proof of droplet-based microreactor and selective transportation of waters with different volume was provided. This study provides a new method for preparation of superhydrophobic surfaces with tunable adhesion, which not only offers the further principle for the fabrication of tunable adhesive superhydrophobic surfaces, but also can be potentially used in many important applications, such as micro-fluidic devices and chemical microreactors.

Designing Heterogeneous Chemical Composition on Hierarchical Structured Copper Substrates for the Fabrication of Superhydrophobic Surfaces with Controlled Adhesion

Controlling water adhesion is important for superhydrophobic surfaces in many applications. Compared with numerous researches about the effect of microstructures on the surface adhesion, research relating to the influence of surface chemical composition on the surface adhesion is extremely rare. Herein, a new strategy for preparation of tunable adhesive superhydrophobic surfaces through designing heterogeneous chemical composition (hydrophobic/hydrophilic) on the rough substrate is reported, and the influence of surface chemical composition on the surface adhesion are examined. The surfaces were prepared through self-assembling of mixed thiol (containing both HS(CH2)9CH3 and HS(CH2)11OH) on the hierarchical structured copper substrates. By simply controlling the concentration of HS(CH2)11OH in the modified solution, tunable adhesive superhydrophobic surfaces can be obtained. The adhesive force of the surfaces can be increased from extreme low (about 8 μN) to very high (about 65 μN). The following two reasons can be used to explain the tunable effect: one is the number of hydrogen bond for the variation of surface chemical composition; and the other is the variation of contact area between the water droplet and surface because of the capillary effect that results from the combined effect of hydrophilic hydroxyl groups and microstructures on the surface. Noticeably, water droplets with different pH (2-12) have similar contact angles and adhesive forces on the surfaces, indicating that these surfaces are chemical resistant to acid and alkali. Moreover, the as-prepared surfaces were also used as the reaction substrates and applied in the droplet-based microreactor for the detection of vitamin C. This report provides a new method for preparation of superhydrophobic surfaces with tunable adhesion, which could not only help us further understand the principle for the fabrication of tunable adhesive superhydrophobic surfaces, but also potentially be used in many important applications, such as microfluidic devices and chemical microreactors.

Simulation of the influence of surface chemical composition on internal gas flow at large Knudsen numbers

On the basis of the developed model, an attempt to describe a rarefied gas flow in the cylindrical channel, whose surface chemical composition conforms with the real experimental conditions, has been made. During the modeling two cases are considered: the atomically clean silver channel surface and the surface fully covered with the adsorbate, which is simulated by oxygen according to the data of the Auger-spectroscopic analysis. The gas–surface interaction process is based on the molecular dynamic principle. Thermal vibrations of the surface atoms are also considered. The obtained results of calculation are compared with experimental data.

Influence of Surface Treatments on the Mechanical Strength of Hotmelt Adhesive Joints Made of Cartonboards

The influence of surface treatments including pigment coating, surface sizing and calendering on the mechanical strength of hotmelt adhesive joints in pilot made cartonboards was studied. The mechanical strength of the joints was investigated using the Y-peel test device at 23°C and 50% relative humidity. Some of the samples were investigated with respect to the failure mode by scanning electron microscopy. The surfaces were characterized in terms of surface roughness, surface chemical composition, and adhesion behaviour. A strong adhesive bond displayed fibre tear. In addition to fibre tear, interfacial failure, i.e., failure between the cartonboard and the adhesive, was the main reason for fracture in the bonded assembly. The most important factor controlling the integrity of adhesive joints seemed to be the real contact area. The adhesive joints showed significantly higher strength when the hotmelt adhesive was first applied onto the rougher cartonboard of the assembly and then the smoother cartonboard was pressed on the adhesive than vice versa. The surface roughness of cartonboards mainly depended on whether the surface was pigment coated or not. Calendering displayed only a minor effect. No clear influence of surface chemical composition of the cartonboards on the adhesive joint strength was found due to the fact that changes in surface chemistry in this study also led to changes in surface roughness. The strongest adhesive joint was created between two medium-rough and surface-sized cartonboards.

Effect of surface composition and roughness on the apparent surface free energy of silica aerogel materials

Surface chemical composition and morphology play an important role in determining the superhydrophobic behavior of solids. To provide insights on the influence of surface chemical composition and roughness on superhydrophobic behaviour of tetramethoxysilane based silica aerogel materials over a wide range, we have carried out a quantitative study of the effect of hydrophobic agent on contact angle and surface free energy of silica aerogels. The apparent surface free energy values were calculated using Zisman method and validated by Fowkes-Girifalco-Good theory.

Influence of Surface Chemical Composition on UV-Varnish Absorption into Permeable Pigment-Coated Paper

Fluorocarbon, organosilicon, and hydrocarbon plasma coatings were used to modify the surface of permeable pigment-coated paper, and their impact on UV-varnish absorption was investigated. According to mercury porosimetry results, the plasma coatings had no influence on the porous structure of the paper. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) results showed characteristic surface chemical compositions for each plasma coating. The fluorocarbon plasma coating increased the UV-varnish contact angles significantly, whereas the hydrocarbon plasma coating had no clear influence. When the UV varnish was applied with a flexography unit including nip pressure, the role of surface chemical composition seemed to become minimal. The viscosity of the UV varnish was shown to impact the absorption rate with and without external pressure.

Molecular beam epitaxy of GaSb on ZnTe/GaAs: Influence of the chemical composition of ZnTe surface

We have studied the molecular beam epitaxy (MBE) of GaSb films on GaAs (0 0 1) substrates by using ZnTe as a new buffer layer. GaSb films were grown on two distinct ZnTe surfaces and the influence of surface chemical composition of ZnTe on the morphological and structural properties of GaSb films has been investigated. Initial 2-dimensional (2D) growth of GaSb films is obtained on Zn-terminated surface consequently smooth morphology and high crystal quality GaSb films are achieved. The thin GaSb film (0.4 μm) grown on Zn-terminated ZnTe surface reveals considerably narrow X-ray diffraction linewidth (113 arcsec) along with small residual strain, which strongly supports the availability of ZnTe buffer for the growth of high-quality GaSb film.

Local Electrochemical Studies and Surface Analysis on Worn Surfaces

Specimens of duplex stainless steel UNS S32304 immersed in distilled water were worn under sliding friction conditions. The electrochemical microcell technique and local Auger spectroscopy were then applied to these heterogeneous surfaces to determine the influence of surface chemical composition and surface defects on the electrochemical behavior of each phase of the stainless steel in and out of the wear track. Experiments were performed both in NaCl, pH 3 (where the passive film is stable), and HCl (where an active peak is observed). In addition, the scanning vibrating electrode technique was combined with a modified microcell to study microgalvanic processes between the surrounding passive surface and the track at the OCP value.

The influence of surface chemical composition on the adsorption of xyloglucan to chemical and mechanical pulps

Adsorption kinetics of xyloglucan (XG) onto bleached chemical and mechanical wood pulps were studied to better understand the application of this plant polysaccharide to the modification of key industrial cellulosic materials. Bleached pulps prepared by the kraft process adsorbed significantly larger amounts of xyloglucan than did thermomechanical pulps (TMP) and chemi-thermomechanical pulps (CTMP). The ability of pulps to adsorb xyloglucan was intimately related to the surface amounts of cellulose, lignin and extractives, as determined by electron spectroscopy for chemical analysis (ESCA). The distribution of absorbed XG on bleached pulp fibers was examined with an XG-fluorescein conjugate (XG-FITC), which was prepared by xyloglucan endotransglycosylase (XET, EC 2.4.1.207)-mediated incorporation of fluorescein-labeled xyloglucan oligosaccharides (XGO-FITC) into XG. Fluorescence microscopy revealed that XG-FITC preferentially adsorbed on fiber surfaces, and was adsorbed in higher amounts to chemical pulps than mechanical pulps, as observed for the unmodified parent polysaccharide. Addition of hybrid aspen XET (PttXET16A) and XGO-FITC to bleached and unbleached mechanical pulps indicated that the amount of enzyme-accessible xyloglucan presented on TMP and CTMP surfaces is low.

Influence of surface chemical composition on the reliability of Al/Cu bond in electronic devices

Four chemically different copper surfaces, as revealed by ESCA, have been ultrasonically bonded to Al/Mg wires. The pull strength of the bond is influenced by this different chemical composition and is dramatically changed by stress conditions. A high temperature storage (200°C) is in this respect less effective then a water vapour pressure environment (121°C, 1.04 atm) especially if traces of halogens are there present. A thick (>40 Å) Cu 2O oxide layer on top of the copper used for the Al/Cu interconnections is found to cause large percentage of intermittance in resin encapsulated finite electronic devices. The failure percentage increases in stress conditions. The wire lift off does not occur, within the limit of practical use, when the thickness of the Cu 2O overlayer on top of the copper used for the interconnection of the finite device, is of the order of 5 Å. The interfacial chemistry is therefore shown to be a dominant factor in determining the reliability of the Al/Cu bond in operating conditions.