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With the rapid development of the photovoltaic industry, the demand for crystalline silicon has significantly increased. Water-based waste slurry generated from silicon wafer cutting with diamond wire is a byproduct, presenting considerable potential for reutilization. However, the presence of moisture can lead to silicon oxidation and SiO2 layer formation on the surface, hindering the recovery of high-purity silicon. In this study, the first-principles was employed for investigating the adsorption property of H2O on Si (111) and Si (100) surfaces, based on density functional theory. The results indicate that H2O can spontaneously adsorb on both the (111) and (100) surfaces of Silicon, and the affinity of H2O for the Si (111) surface being stronger than the Si (100) surface. Furthermore, Mulliken charge calculations and differential electron density analysis confirm that charge transfer of H, O and Si atoms occurs during the adsorption process between Si and H2O. The Si–O bonds formed on the Si (111) surface exhibit greater covalency compared to the Si (100) surface, suggesting that the Si (111) face is more susceptible to oxidation than the Si (100) face. This study provided theoretical insight into the adsorption of silicon in water at the atomic level, which is significant for deepening the understanding of silicon's oxidation mechanisms. [ABSTRACT FROM AUTHOR]

This research is aimed towards a facile one-step preparation of magnetic poly(styrene-glycidyl methacrylate)-Fe3O4 nanocomposite particles named as P(S-GMA)-Fe3O4. The nanocomposite particles are prepared by a simultaneous free-radical copolymerization and co-precipitation of Fe2+ and Fe3+ salts. Two variable w/w ratios of styrene to GMA (98/2 and 96/4) are used. But, the overall copolymer to iron oxide ratio is kept identical. The structural analyses and morphology revealed the uniform distribution of Fe3O4 nanoparticles and the nanocomposites showed paramagnetic property. The potentiality of nanocomposite particles as glucose bisenosors via adsorption of glucose oxidase (GOD) is investigated using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). A comparative analysis of the glucose concentration dependent current response suggested that the modified electrode fabricated from P(S-GMA)-Fe3O4(2) (w/w ratio, 98/2) possessed superior response to other electrodes made from PS, P(S-GMA), PS-Fe3O4 and P(S-GMA)-Fe3O4(4) (w/w ratio, 96/4), respectively. The P(S-GMA)-Fe3O4(2)/GOD/Pt biosensor could measure glucose in the range of 2.2 × 10− 4 to 6.0 × 10− 3 M with a sensitivity of 14.47 µA mM− 1 and exhibited a detection limit of 5.07 µM at a signal to noise ratio of 3. The value of Michaelis-Menten constant (Km) is calculated as 0.019 mM. Overall results indicate that P(S-GMA)-Fe3O4(2) nanocomposite prepared in one-step is suitable for use in glucose biosensors. [ABSTRACT FROM AUTHOR]

Iron phosphate, Fe2 (HPO4)3*4H2O, is synthesized at ambient temperature, using the inorganic sol–gel method coupled to the microwave route. The experimental conditions for the gelling of Fe (III)-H3PO4 system are previously defined. Potentiometric Time Titration (PTT) and Potentiometric Mass Titration (PMT) investigate the acid–base surface chemistry of obtained phosphate. Variations of surface charge with the contact time, Q a function of T, are examined for time contact varying in the range 0–72 h. The mass suspensions used for this purpose are 0.75, 1.25 and 2.5 g L−1. The point of zero charge (PZC) and isoelectric point (IEP) are defined using the derivative method examining the variations dpH d t = f pH , at lower contact time. A shift is observed for PZC and IEP towards low values that are found to be 2.2 ± 0.2 and 1.8 ± 0.1, respectively. In acidic conditions, the surface charge behavior of synthesized phosphate is dominated by > POH ¯ group which pKa = 2.45 ± 0.15. Q against T titration method is performed for synthesized Fe2 (HPO4)3*4H2O in NaCl electrolytes. The maximal surface charge (Q) is achieved at the low solid suspension. Hence, for m = 0.75 g L−1, Q value of 50 coulombs is carried at μ = 0.1 and pH around 12, while charge value around 22 coulombs is reached in the pH range: 3–10. The effect of activation time, Q and pH on sodium insertion in iron phosphate, were fully evaluated. To determine the optimal conditions of the studied process, mathematical models are used develop response surfaces in order to characterize the most significant sodium interactions according to the variation of the pH, Q, the contact time and the contents of the synthesized material. [ABSTRACT FROM AUTHOR]

In addition to traditional metal oxides, N-containing compound would become efficient catalyst for H2S selective oxidation. TaON and Ta3N5, taking as examples, with porous structure are able to selectively oxidize H2S into sulfur. TaON exhibits ca. 99% H2S conversion and ca. 89% sulfur selectivity at 250 ℃, while Ta3N5 exhibits near complete H2S conversion (~ 100%) and 86% sulfur selectivity at 250 ℃. TaON of lower N content shows higher sulfur selectivity (~ 90–100%) above 130 ℃, compared with that (~ 86–95%) over Ta3N5. Whereas, Ta3N5 of higher N content demonstrates higher H2S conversion (~ 30–40%) below 160 ℃, compared with that (~ 6–30%) over TaON. Temperature programmed desorption results show that Ta3N5 owns larger amount of acid sites and weaker basic sites than TaON. Over Ta3N5, the reactant molecules could dissociatively adsorb on acid sites more frequently and could be easier to move across the weaker basic sites, thus increasing probability for reaction at low temperature. Manipulating both cations and anions in N-containing compound can alter surface property for optimization of selective H2S oxidation. [ABSTRACT FROM AUTHOR]

In the present study, we evaluated the antimicrobial activity of passion fruit peel extract (PPE) against Escherichia coli O157:H7 and Listeria monocytogenes. The application of PPE using an electrostatic spraying system for the disinfection of fresh-cut Lollo Rossa and beetroot leaves was also examined and compared with conventional PPE washing. Time-kill assays indicated that PPE had antibacterial activity against Escherichia coli O157:H7 and Listeria monocytogenes, effectively reducing the populations of the pathogenic bacteria within 3 h following treatment with 6 mg/mL PPE. Confocal laser scanning microscopy and scanning electron microscopy showed that PPE treatment caused bacterial cell death by damaging the cell membrane. PPE treatment produced significant decontamination against the pathogens on fresh-cut vegetables. Electrostatic spraying of 6 mg/mL PPE for 20 s decreased the populations of pathogenic bacteria on Lollo Rossa and beetroot leaves by 2.29–2.86 log CFU/g, regardless of the difference in the contact angle and surface roughness of the vegetables. Our results showed that electrostatic spraying of PPE was more effective than washing with PPE. Electrostatic spraying of PPE did not affect the color and texture of fresh-cut Lollo Rossa leaves during storage, suggesting that it can be used as a novel disinfection method. [ABSTRACT FROM AUTHOR]

In order to understand the relationship among enzymatic hydrolysis of lignocellulose, cellulase adsorption characteristics, and physicochemical properties of lignocellulose, a series of investigations was conducted, including composition, surface morphology, chemical bonds, functional groups, pore characteristics, cellulase accessibility, productive cellulase adsorption, cellulase adsorption isotherm, and kinetics of sodium hydroxide (NaOH) and ammonia-treated sugarcane bagasse (SCB) substrates. The results showed that the hydrolysis efficiency of NaOH-treated SCB (87.85%) was higher than that of ammonia-treated SCB (33.65%) and NaOH-treated SCB had less lignin, looser surface, and larger specific surface area and pore volume. This suggested that better accessibility of NaOH-treated SCB to cellulase resulted in higher enzymatic hydrolysis efficiency. The data on cellulase adsorption showed that NaOH-treated SCB had more productive adsorption, less non-productive adsorption, better adsorption capacity, and smaller binding strength with cellulase, which was also beneficial to the enhancement of enzymatic hydrolysis of NaOH-treated SCB. In addition, it was found that once cellulase molecules were adsorbed onto these two SCB substrates, two types of bonds as follows might be formed: one was C-OR (R means organic groups) and the other was C-OH··NH that was a type of hydrogen bond formed between the hydrogen of amino group in cellulase and the hydroxyl group in lignocellulose. This study would help further learn the link between lignocellulosic substrate characteristics and enzymatic hydrolysis or cellulase adsorption properties of lignocellulose. [ABSTRACT FROM AUTHOR]

In this study, Ag/AgCl photocatalysts were prepared by using chloride ionic liquid (IL) as a chlorine source. The structure, composition, morphology, light response ability and surface properties of IL-AgCl were characterized by X-ray diffraction, scanning electron microscope, X-ray photoelectron spectroscopy, Raman spectroscopy, UV–Vis diffuse reflection spectra, specific surface area and surface photovoltage spectrum. The photocatalytic activity of the samples was investigated by measuring the residual concentration of rhodamine B used as a simulated pollutant. The experimental results show that the ionic liquid can promote the stability of AgCl, furthermore, all the IL-AgCl photocatalysts have a higher separation rate of photogenerated charge pairs than the reference AgCl. The surface properties and photocatalytic activity of AgCl prepared tightly relate to the type of IL used, among all the AgCl prepared, AgCl prepared by 1-carboxyethyl-3-methyl-imidazolium chloride has the best catalytic activity. [ABSTRACT FROM AUTHOR]

A novel bimetallic bifunctional Pt–NiP/Hβ isomerization catalyst was successfully prepared by introducing a small amount of noble metal Pt into the NiP on the Hβ carrier. The catalyst demonstrated superior catalytic activity to Pt/Hβ and NiP/Hβ catalysts for n-hexane isomerization, due to the good surface property, the synergistic effect of the two metals, the suitable match between acid site and metal site, as well as good reduction stability. The effects of Pt loading and NiP addition amount on the surface property were studied comprehensively through a series of characterization, and the correlation among surface property with catalytic behavior was also analyzed. The results indicated that the Pt (0.1 mol%)–NiP (10 mol%)/Hβ catalyst had good structural characters, surface acid property and an uniform distribution of NiP and Pt active components on surface, which is helpful to obtain a highly efficient catalytic performance. Additionally, the influence of reduction/reaction conditions on the catalytic activity, as well as the catalyst tolerance to water and thiophene sulfur, was investigated furtherly. [ABSTRACT FROM AUTHOR]

In this paper, 3-isocyanatepropyl triethoxysilane (IPTS) was synthesized using one-pot reaction using 3-aminopropyl triethoxysilane (APTES) and triphosgeneas as the raw materials. IPTS was then reacted with three kinds of perfluoroalkyl alcohol to obtain 3-(1H,1H,2H,2H-perfluoroalkoxyamidepropyl)-triethoxysilanes with different fluoroalkyl chain lengths. The silicon wafer was etched to obtain an active and coarse surface followed by coating with self-assembled monolayer (SAMs) using fluoroalkylsilane as materials. AFM were used to reflect the variation of the surface morphologies and roughness of self-assembled films before and after coating. ATR-IR test indicated that a combination of possible bonding forms the SAMs. EDS was used to characterize the distribution of the elements on the SAMs. The result of contact angle testing and surface energy counting showed that the SAMS have good water- and oil repellency, which improved with the increment of fluoroalkyl chain length. XPS were used to characterize the change of surface element content of SAMs before and after heat treatment, which resulted in the microphase separation on the film surfaces and made the fluoroalkyl migrate from the internal of the monolayer to the outermost surface. After heating, the fluoroalkyl accumulated on the surface, which lowered the surface energy further and obtained the better water- and oil repellency. [ABSTRACT FROM AUTHOR]

To clarify the adsorption mechanism of multi-ions on biochars in competitive environment is very important for the decontamination of co-existed heavy metals. Herein, tobacco stem was pyrolyzed in different temperatures with selected residences to obtain biochars with various surface chemistry. Then the adsorption of co-existed typical heavy-metal ions like lead, cadmium, and copper was studied, followed with systematic analysis of surface properties of the post-adsorption biochars. After carefully examining the adsorption performance and surface property alteration of the demineralized biochars, the adsorption mechanism of multi-ions in competitive environment was discovered. Lead showed the most competitive nature with co-existence of cadmium and copper, but the adsorption capacity reduced significantly with the removal of minerals. Combined with the observation of large amount of lead containing crystals on the post-adsorption biochars, the main adsorption mechanism of lead should be precipitation. The adsorb capability of copper barely changed for biochars with and without minerals, which suggests the best affinity of copper on surface functional groups even with large content of competitors. Biochar that pyrolyzed in 700 °C for 6 h that contained more aromatic structures showed the highest sorbing capability of cadmium, which suggested the dominant position of cation-π interaction in cadmium removal. [ABSTRACT FROM AUTHOR]

Cellulose and chitosan have similar structure both with the β(1→4) linked functional groups, e.g., the former linked the D-glucose units and the latter linked D-glucosamine units. Our recent studies have found that these different functional groups have oppositely electric-responses in an electric-assisted capillary rise adsorption process (J Phys Chem B 120: 1121-1125, 2016). This work furthermore reported the electric-wetting behavior of cellulose and chitosan. With the voltage increase, the contact angles between the probe polar solvent and these two biopolymers would be reduced consistently, to lead the surface free energy reduction for cellulose and enhancement for chitosan. This is because that the voltage increase would lead the Lewis acid-base properties reduction for cellulose and enhancement for chitosan. The reason is that the β(1→4) linked D-structures are polar groups with oppositely electric-responses. Therefore, under the electric wetting condition, the polarity of β(1→4)-linked D-glucose would be reduced and the β(1→4)-linked D-glucosamine would be enhanced, respectively. [ABSTRACT FROM AUTHOR]

Based on the working principles of particle bed comminution, particles produced by high-pressure grinding rolls (HPGR) have surface properties different from particles produced by other grinding patterns, which exert great influence on mineral flotation. Flotation performances of calcite particles under different grinding patterns involving the use of HPGR, a jaw crusher, a dry ball mill, a wet ball mill, and a wet rod mill were studied using single mineral flotation tests. The surface properties of the particles under different grinding patterns were characterized to determine the flotation performance variation in terms of specific surface area, particle size distribution, AFM, XPS, and zeta potential. The results show that particles ground by HPGR exhibited improved flotation performance within the lower range of grinding fineness in both NaOL and dodecyl amine flotation systems compared to the particles prepared using other grinding patterns. Specific surface area, particle size distribution, surface roughness, Fe(III) contamination, binding energy, and zeta potential are greatly influenced by grinding patterns, which is the main cause of the flotation performance variation. [ABSTRACT FROM AUTHOR]

Amphiphilic fluorocopolymer P (PEGMA)-co-P (DFHM) is prepared by hydrophobic dodecafluorohrptyl methacrylate (DFHM) and hydrophilic poly (ethylene glycol) methyl ether methacrylate (PEGMA) monomers via atom transfer radical polymerization (ATRP). The self-assembled colloids of P (PEGMA)-co-P (DFHM) in ethanol, dimethylformamide (DMF), tetrahydrofuran (THF), and chloroform (CHCl) solutions are discussed according to solvent dielectric constants ( ε = 38.3-4.8). The hydrophilic/hydrophobic property, protein resistance, and adhesive strength of films formed by these colloids are evaluated based on the surface morphologies and chemical compositions. P (PEGMA)-co-P (DFHM) can self-assembly into core-shell micelles composed of P (PEGMA) shell and P (DFHM) core (~130 nm) as 500-600 nm in DMF, 300-400 nm in ethanol, and 200-250 nm in THF and CHCl solutions. These colloids provide the film surfaces with high fluorine content (39.40-41.70 wt%) to indicate the migration of fluorine-containing groups onto the film surface during the film formation and therefore the obvious hydrophilic/hydrophobic properties (94.3°-102.4° water contact angles and 58.5°-60.2° cetane contact angles). Comparatively, DMF-casted film gains the highest surface roughness (Ra = 0.98 nm), the lowest fluorine content (39.40 wt%), and the highest surface free energy (20.41 mN m) due to its large size of colloids, but CHCl-casted film gives the lowest surface free energy (17.82 mN m). The adhesive strength for DMF- and ethanol-casted films (210 and 168 N) proves higher than THF- and CHCl-casted films (105 and 63 N), while DMF-casted film shows much better protein resistance (Δ f = −15.0 Hz) than other three films (Δ f = −17-20 Hz). It is believed that the obtained P (P EGMA)-co-P(DFHM) could have a promising application as solvent-dependent and protein-resistance coatings. [ABSTRACT FROM AUTHOR]

Fluorinated polyacrylate particles with spherical (SP) and core-shell (CS) structures have been prepared via emulsion polymerization. Morphologies of SP and CS latex particles were observed by transmission electron microscope (TEM). The copolymer and the film were characterized by Fourier transform infrared spectroscopy (FT-IR), F NMR, atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS), and thermogravimetry (TG-DSC) analyses. Fluorinated components in the copolymer were found to aggregate at the film surface, and the core-shell structure of latex particles contributes to occurrence of phase separation at the film surface. The film prepared from core-shell latex particles exhibits more satisfied water repellency than that obtained from spherical latex particles. Fluorine components at SP and CS film surfaces present significantly different aggregation behaviors. [ABSTRACT FROM AUTHOR]

Poly(silsesquioxane)methylsiloxane (PSS) was prepared by the hydrosilylation and hydrolysis reactions using trichlorovinylsilane and dimethyldichlorosilane as starting materials. Poly(fluorosilsesquioxane)methylsiloxane (FPSS) was obtained via a single electron transfer addition reaction of PSS with perfluorobutyl iodide followed by Zn-mediated reduction of iodide. FT-IR, H NMR, F NMR and C NMR indicated the structures of PSS and FPSS. The surface chemical composition and element distribution of polymer films were measured using X-ray Photoelectron Spectroscopy. In addition, Atomic Force Microscopy images showed that there were numerous pinnacles that were generated on the rough surface of films by the segregation of fluoroalkyl side chains at the polymer-air interface. The relative static contact angles of PSS and FPSS films toward water were 105.1° and 119.3°, respectively. The FPSS was characterized to possess of better water repellent property because of the segregation and enrichment of fluoroalkyl chains on the surface of FPSS. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Alignment characteristics of nematic liquid crystal (LC) on the surface of conjugated semi-conducting polymer blends with a comb-like polymer were studied. Conoscopic polarized optical microscope images show vertical alignment of LC on the blend films regardless of blend ratio. The LC alignment behavior on the blended film surface can be explained by a preponderance of comb-like polymers at the film surface. The mobility values of organic thin film transistors (OTFT) prepared with the blend film as an active layer are found to be similar to those with a pure conjugated semi-conducting polymer film. This result suggests a novel route for effectively reducing the amount of active semi-conducting polymer without significant deterioration of charge carrier mobility in an OTFT device. Since the LC alignment can be controlled on the surface of channel layer of OTFT by employing the polymer blend as the semi-conducting layer, the LC alignment and OTFT performance with the blend composition can be investigated simultaneously. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Colloidal silica is prepared by hydrolysis of TEOS, direct oxidation of Si powder, condensation of silicic acid, etc. There are differences in surface reactivity of silica particle due to the preparation routes. Therefore, it is useful to evaluate surface properties accurately in order to understand the physiochemical properties of the products. The surface charge density, site density and zeta potential with respect to three types of colloidal silica were estimated and discussed. The surface charge density was different depending on preparation method. It is decreasing in the order of direct oxidation, ion exchange, TEOS hydrolysis. The zeta potential is decreasing in the order of ion exchange, TEOS hydrolysis, direct oxidation. The order in surface charge density is different from that in zeta potential because of the difference in stability depending on the particle size and surface charge density. [ABSTRACT FROM AUTHOR]

Surface and structural properties of cellulose hydrogel prepared from LiOH/urea solvent with alcoholic coagulation were examined. As coagulants, alcohols from methanol to butanol were employed. Alcohol with high water miscibility (MeOH, EtOH, 1-PrOH, 2-PrOH, and t-BuOH) gave a nano-porous structure consisting of a fibrous network of cellulose, while alcohol with low water miscibility (1-BuOH, 2-BuOH, i-BuOH) showed aggregation of a fibrous structure because of large shrinkage during the coagulation process. Congo red adsorption measurement showed that an increase in the carbon number of alcohol brought about a less hydrophobic surface. This is likely to occur because the alkali/urea/cellulose complex was formed during the coagulation process in the case of ethanol, propanol, and butanol, leading to a higher crystalline content of cellulose II, the surface of which is thought to be highly hydrophilic. [ABSTRACT FROM AUTHOR]

We sought to study the corrosion behavior and surface properties of a commercial cobalt–chromium (Co–Cr) alloy which was fabricated with selective laser melting (SLM) technique. For this purpose, specimens were fabricated using different techniques, such as SLM system and casting methods. Surface hardness testing, microstructure observation, surface analysis using X-ray photoelectron spectroscopy (XPS) and electrochemical corrosion test were carried out to evaluate the corrosion properties and surface properties of the specimens. We found that microstructure of SLM specimens was more homogeneous than that of cast specimens. The mean surface hardness values of SLM and cast specimens were 458.3 and 384.8, respectively; SLM specimens showed higher values than cast ones in hardness. Both specimens exhibited no differences in their electrochemical corrosion properties in the artificial saliva through potentiodynamic curves and EIS, and no significant difference via XPS. Therefore, we concluded that within the scope of this study, SLM-fabricated restorations revealed good surface properties, such as proper hardness, homogeneous microstructure, and also showed sufficient corrosion resistance which could meet the needs of dental clinics. [ABSTRACT FROM AUTHOR]

Protein-polymer hybrids consisting of protein and natural polymers or synthetic polymers exhibit superior properties to unmodified proteins, generating a high demand for these materials in the fields of medicine, biotechnology, and nanotechnology. Herein, protein-polysaccharide hybrids were fabricated via the formation of an amide bond between bovine serum albumin (BSA) and chitosan (CS) using N-ethyl- N-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) as the couple reagent. FTIR spectrum reveals that the carboxyl group of BSA conjugated with the amino group of chitosan backbone. The molecular weight of BSA-CS hybrids was identified by matrix-associated laser desorption ionization time of flight mass spectra (MALDI-TOF MS) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The maximum number of chitosan chains binding to each BSA molecule was estimated as 6, and the optimal number was estimated as 2. In addition, the secondary structure and surface property of BSA were dependent upon the number of polymer conjugating on protein. The secondary structure of BSA was not significantly changed, if a few chitosans were coupled with BSA. By further increasing the molar ratio of chitosan to BSA, the secondary structure of BSA was markedly damaged. The surface's negative charges of modified BSA also decreased. The result of native polyacrylamide gel electrophoresis (native-PAGE) also demonstrated the changes in surface charges and molecular weight of BSA-CS hybrids. [ABSTRACT FROM AUTHOR]

The surface transport properties of naturally oxidized p-type HgCdTe thin film were investigated in the magnetic-field region 0-14 T and in the temperature region 8-300 K. The Hall electron concentration increases with temperature, while the surface concentration of the two-dimensional electrons in the naturally oxidized surface, calculated by Shubnikov-de Haas oscillations, decreases as temperature increases at temperatures below 20 K. The contradiction and the extraordinary quantum Hall filling factors are accounted for by assuming extra bulk-like electrons in the surface region, which dominate the surface transport properties at temperatures over 8 K. [ABSTRACT FROM AUTHOR]

A series of cationic polyurethane-fluorinated acrylic hybrid latex (PUFA) have been synthesized by solvent-free method. In the method, vinyl monomers acted as dilution agent and the polyurethane (PU) having quaternary ammonium groups acted as macromolecular emulsifier without using any other solvent and surfactant. The structure and properties of PUFA were characterized by Fourier transform infrared spectroscopy (FT-IR), F nuclear magnetic resonance (F NMR), particle size distribution (PSD) analysis, transmission electron microscopy (TEM), contact angle (CA), surface free energy analysis, scanning electron microscope (SEM) equipped with energy dispersive X-ray spectrometry (EDS), and thermogravimetric (TG) analysis. The FT-IR, F NMR, and EDS confirmed that the FA monomer had been introduced into the chain of the PUFA hybrid polymer. The PSD analysis indicated the particles of PUFA were smaller than corresponding pure PU dispersion and narrower in particle size distribution. The CA and surface free energy analysis proved the PUFA hybrid latex film with fluorine possessed higher contact angle and lower surface free energy in contrast with the film without fluorine. The FPUA films exhibited good surface property which could be enhanced at higher annealing temperature. The EDS of PUFA confirmed the fluorine enrichment on the surface of PUFA. TG analysis suggested the PUFA hybrid latex film had a better thermal stability than pure PU. [ABSTRACT FROM AUTHOR]

Poly[2, 6-diimidazo (4,5-b:4',5'-e) pyridinylene-1,4(2,5-dihydroxy) phenylen] (PIPD) was synthesized and the obtained PIPD/PPA dope was directly spun into fibers via a dry-jet wet-spinning process for the first time. The obtained polymers were mainly characterized by ATR-FTIR and dynamic contact angle analysis. FTIR spectrum of the PIPD fibers indicates that the product was consistent with the target product. The contact angle measurements show that the wetting process of water on PIPD fibers is apparently faster than that on PBO fibers. The axial compression bending test indicates that PIPD fibers showed larger compressive strength compared with that of PBO fibers under the same axial compressive load. Meanwhile, the TGA test results indicate that the PIPD fibers have excellent thermal stability. [ABSTRACT FROM AUTHOR]

Silk fibroin film (SFF) has been widely used in biomaterials. SFF is usually prepared from a regenerated silk aqueous solution and its properties depend remarkably on the preparation conditions. However, the effect of the silk fibroin concentration ( C0) on the SFF surface properties as well as the cytocompatibility has rarely been investigated. In this work we prepared a series of Bombyx mori SFFs by casting SF aqueous solutions with the concentration from 10° to 102 mg/mL on TCPS substrate at 60°C. The test results of atomic force microscopy, attenuated total reflection Fourier transform infrared and contact angles analysis showed that the film surface roughness and β-sheet structure increased with the increase of C0, whereas the surface hydrophilicity increased with the decrease of C0. The in vitro clotting time measurement results revealed that the SFFs prepared from the thinner solution showed a longer APTT (activated partial thromboplastin time) and TT (thrombin time). The results of microscopy and MTT assay also revealed that cell adhesion and growth were enhanced on the SFF cast from lower C0 for fibroblasts. In contrast, endothelial cells showed a similar behavior on all those films that were prepared from the solution in different concentrations. [ABSTRACT FROM AUTHOR]

Surface modification with dielectric barrier discharge (DBD) plasma was carried out at atmospheric pressure (argon as the discharge gas) to improve the biocompatibility of hydrophobic acrylate intraocular lens (IOL). Changes of the plasma-treated IOL surface in chemical composition, morphology and hydrophilicity were comprehensively evaluated by X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and water contact angle (WCA) measurements. The surface biocompatibility of the untreated and plasma-treated IOLs was compared with the adhesion behavior of platelets, macrophages and lens epithelial cells (LECs) in vitro. After DBD plasma treatment, the hydrophilicity of the IOL surface was obviously improved. The changes in WCA with treatment extension may be attributed to both the introduction of oxygen or/and nitrogen-containing polar groups and the increase of surface roughness induced by plasma etching effect. The existence of low molecular weight oxidized material (LMWOM) was proved on the plasmatreated IOL which was caused by the chain scission effect of the plasma treatment. The plasma-treated IOLs resisted the adhesion of platelets and macrophages significantly. The LECs spreading and proliferation were postponed on the IOLs plasma-treated for more than 180 s, with a well maintained epithelial phenotype of LECs. The IOL biocompatibility was improved after the DBD plasma treatment. We speculate that slighter foreign-body reaction and later incidence of anterior capsule opacification (ACO) may be expected after implantation of the argon DBD plasma-treated IOL. [ABSTRACT FROM AUTHOR]

Monodisperse magnetic nanoparticles (MNPs) were synthesized by thermal decomposition of iron-oleate and functionalized with silanes bearing various functional groups such as amino group (NH2), short-chain poly(ethylene glycol) (PEG), and carboxylic group (COOH). Then, silanes-functionalized magnetic nanoparticles (silanes-MNPs) were incubated in cell culture medium plus fetal calf serum to investigate the effects of proteins from culture medium on surface property of MNPs. Zeta potential measurements showed that although surface charges of silanes-MNPs were different, they exhibited negative charges at neutral pH and approximate isoelectric points after they were incubated in cell culture medium. The reason was that silanes-MNPs could easily adsorb proteins from culture medium via non-covalent binding, resulting in the formation of protein-silanes-MNPs conjugates. Moreover, silanes-MNPs with various functional groups had different adsorption capacity to proteins, as confirmed by Coomassie blue fast staining method. The in vitro cell experiments showed that protein-silanes-MNPs had higher cellular uptake by cancer cells than silanes-MNPs. [ABSTRACT FROM AUTHOR]

The synthesis of a novel aromatic diamine compound containing phosphorylcholine (PC) group was carried out to prepare aromatic polyamides with PC moiety, in order to develop durable biocompatible polymer materials. The desired diamine compound, 2-(3,5-diaminophenylcarbonyloxy)ethyl phosphorylcholine (DAPC), was prepared from a reaction of 2-[2-(3,5-dinitrophenylcarbonyloxy)ethyl]-2-oxo-1,3,2-dioxaphospholane with trimethylamine, followed by the reduction of the dinitro group by H2/Pd. The starting phospholane compound was synthesized by a condensation reaction of 2-hydroxyethyl 3,5-dinitrobenzoate with 2-chloro-2-oxo-1,3,2-dioxaphospholane. The polycondensation of DAPC with 4,4′-diamino-3,3′-dimethyldiphenylmethane and isophthaloyl chloride gave the copolyamides with different PC contents. From the results of contact angle of water and XPS analysis on the surface of the copolyamide coating films, it was found that PC units were concentrated on the surface after immersed in water. In addition, by using 2,2-bis[4-(aminophenyloxy)phenyl]propane or 2,2-bis[4-(aminophenyloxy)phenyl]hexafluoropropane as a diamine comonomer with DAPC, high molecular weight copolyamides containing PC moiety were obtained to prepare homogeneous coating films. The obtained copolyamides exhibited the high thermal stability, and also the excellent biocompatibility even though the content of PC monomer unit in the copolymer was around 20 mol %, which was confirmed by the platelet adhesion test. Therefore, the introduction of PC group in the side chain of aromatic polyamide was effective to develop the biocompatibility, which would be due to the surface property covered with polar PC units. [ABSTRACT FROM AUTHOR]

The article presents abstracts of several studies on environmental geochemistry. Some of the abstracts presented include "Biogeochemical Cycling of Nutrients in Karstic Catchments, Southwestern China: Linkages to Changes of Eco-Environments," by Congqiang Liu and "Emerging Organic Contamination in China," by Guibin Jiang and colleagues.

The surface properties of solders play an important role in its wettability. The poor wettability of the Sn-9Zn alloy has prohibited its commercial application. In this paper, the solid surface properties of the Sn-9Zn alloy were studied by using X-ray photoelectron spectroscopy (XPS). It was shown from the XPS analysis that zinc is highly enriched on the surface of the Sn-9Zn alloy. Although the zinc concentration on the surface is greater than 9%, lanthanum is accumulated on the surface of the Sn-9Zn-1La alloy. In addition, the analysis of the valence of tin and lanthanum indicated that tin and lanthanum could form complex oxygen-containing salts so that the anti-oxidation of the solder was enhanced, and the wettability of the solder was improved accordingly. [ABSTRACT FROM AUTHOR]

The abrasion behavior of three kinds of warp knitted fabrics, which are normally used for upper sole of footwear, was evaluated. We measured the changes of mechanical and structural properties of each sample as abrasion cycle increased. Each sample showed similar trends in compression and surface properties but there were significant differences in abrasion rate among the samples. The mechanical properties showed remarkable differences with directions. The frictional coefficient (MIU) of fabric surface increased at the beginning of abrasion and decreased as abrasion cycles increased. The weight and thickness of the fabric linearly decreased with abrasion cycles. The surface roughness (SMD) and the compressional resilience (RC) decreased as abrasion cycles increased while compressional energy (WC) increased. [ABSTRACT FROM AUTHOR]

Zirconium hydroxides were obtained by precipitation of zirconium chloride with aqueous ammonia at constant pH followed by hydrothermal treatment The effect of thermal activation of the zirconium hydroxide on physical properties, and the effect of crystalline phase on the surface properties of zirconia were studied. The pressure during the hydrothermal treatment of zirconium hydroxide affected the surface area, particle growth, and phase transformation of the zirconia product. Hydrothermally treated zirconia under atmospheric pressure (LP) shows higher surface area than that under high pressure (HP) and untreated (UT). HP zirconia shows a mixture of tetragonal and monoclinic phase after hydrothermal treatment due to the higher solubility and reprecipitation rate, whereas LP sample shows a tetragonal crystal structure from 600 to 1,050 ℴC. Monoclinic phase zirconia shows greater CO2 and NH3 surface adsorption than amorphous and tetragonal phase zirconia. This suggests that the crystal structure of zirconia strongly affects the amount and strength of the surface adsorption site. [ABSTRACT FROM AUTHOR]