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In this work, 3-aminopropyltriethoxysilane modified FeO nanoparticles (ATPS-FeO) were used to modify glassy carbon electrode for aminopyrine determination. ATPS-FeO showed obviously catalytic activity and adsorptivity towards aminopyrine oxidation proven by the increased oxidation peak current and the decreased oxidation peak potential. The best analytical response was obtained by immobilizing 8 μL 3 mg/mL APTS-FeO dispersion with an accumulation time of 200 s at −0.2 V in 0.1 M phosphate buffer solution (pH 9.0). The oxidation peak current of aminopyrine showed linear relationship with its concentration in the range from 0.5 to 100 and 100 to 1600 μM. The detection limit was 0.1 μM (S/N = 3). The proposed method showed satisfactory repeatability and anti-interference ability. The fabricated electrode was successfully applied to determine aminopyrine in pharmaceutical formulations. [ABSTRACT FROM AUTHOR]

Abstract: A simple, elegant method for the formation of a continuous stationary phase gradient for use in chromatographic separations is described. Its applicability to separation science is demonstrated using thin-layer chromatography as a test case. Gradient stationary phases were formed on activated High Performance Thin-Layer Chromatography (HP-TLC) plates using a newly developed methodology termed “controlled rate infusion”. Specifically, the SiOH groups on the activated HP-TLC plates were reacted with 3-aminopropyltriethoxysilane (APTEOS) in a time dependent fashion by using a programmable syringe pump to control the rate of APTEOS infusion into the deposition reservoir. The shape (profile) of the gradient was controlled by the rate of infusion and imaged by taking advantage of the concentration-dependent color formation reaction between amine groups and ninhydrin. The advantages of such gradients in optimizing the retention and separation of various components in different mixtures were illustrated using mixtures of (1) four weak acids and bases and (2) three widely used over-the-counter drugs. The separation of the individual components on the gradient stationary phase was clearly improved relative to those on either traditional normal-phase TLC plates or uniformly amine-modified TLC plates. Precise control over component retention and separation was also demonstrated by strategically modifying the steepness of the gradient. [Copyright &y& Elsevier]

Abstract: In this study, electrical impedimetric biosensors composed of Au-electrodes were fabricated for the quantitative detection of human serum albumin (HSA), an essential biomarker of liver function. The Au-electrodes were fabricated via a single-step photolithography process, and can be easily integrated in biochips for assessing liver function in the future. The glass sensing surface between two adjacent Au-electrodes was modified with 3-aminopropyltriethoxysilane (APTES) to improve the biocompatibility for its subsequent binding to anti-human serum albumin (AHSA). The sensing surface without AHSA binding was blocked using skim milk powders, preventing possible non-specific bonding HSA conjugation. Biosensors were used to measure HSA concentration for liver function detection. The impedance between two adjacent Au-electrodes of the biosensors applied with various HSA concentrations was directly measured, and quantified using an electrochemical impedance spectroscopy system under AC conditions. The results of plotting both values in log scales indicated the impedance increased linearly with HSA conjugation increase. The limit of HSA detection was about 2′10−4 mg/ml using the electrochemical impedimetric biosensor proposed in this work. This study demonstrates the feasibility of using electrochemical impedimetry as a bio-sensing mechanism to quantify human serum albumin concentration. The sensor proposed in this work also displays great potential for assessing liver function because of its simple detection mechanism, ease of biochip integration, and low cost. [Copyright &y& Elsevier]

In this paper, we report the γ-ray sterilization effects in pH-sensitive polysilicon wire (PSW) sensors using a mixture of 3-aminopropyltriethoxysilane (γ-APTES) and polydimethylsiloxane (PDMS)-treated hydrophobic fumed silica nanoparticles (NPs) as a sensing membrane. pH analyses showed that the γ-ray irradiation-induced sensitivity degradation of the PSW pH sensor covered with γ-APTES/silica NPs nanocomposite (γ-APTES+NPs) could be restored to a condition even better than prior to γ-ray irradiation by 40-min of post-sterilization room-temperature UV annealing. We found that the trapping charges caused by γ-ray sterilization primarily concentrated in the native oxide layer for the pH sensor covered with γ-APTES, but accumulated in the γ-APTES+NPs layer for the γ-APTES+NPs-covered sensor. It is believed that mixing the PDMS-treated silica NPs into γ-APTES provides many γ-APTES/SiO2 interfaces for the accumulation of trapping charges and for post-sterilization UV oxidation, thus restoring γ-ray-induced sensor degradation. The PDMS-treated silica NPs not only enhance the sensitivity of the pH-sensitive PSW sensors but are also able to withstand the two-step sterilization resulting from γ-ray and UV irradiations. This investigation suggests γ-ray irradiation could be used as a highly-efficient sterilization method for γ-APTES-based pH-sensitive biosensors. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the titanium plates, which were modified by NaOH alkali solution, were associated with 3-Aminopropyltriethoxysilane (APTES) films using self-assembled monolayers (SAMs). The surfaces of titanium before and after modification were characterized by scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and attenuated total refraction–Fourier transform infrared spectroscopy (ATR–FTIR). After bonding the APTES films on the modification titanium, the new peaks located around 1095cm−1 attributes to siloxane groups indicating that silane agent had been grafted onto the surface of the modification titanium substrate by SAMs. Following the deposition of APTES films on titanium, significant change were seen in the amounts of oxygen, silicon and carbon present on the titanium surface, which were consistent with the anticipated reaction steps. [Copyright &y& Elsevier]

Abstract: Aminopropylated nanosilica was prepared by a simple sol–gel process from tetraethyl orthosilicate (TEOS) and then it was functionalized with different amounts of 3-aminopropyltriethoxysilane (APS) under toluene reflux. The prepared solids were characterized by means of XRD, FT-IR, TGA–DTA, SEM–EDS, and TEM. Their textural properties were determined by adsorption–desorption isotherms of N2 at 77K. It was proved that the amount of APS used in the preparation process had a great influence on the physicochemical properties of the hybrid organic–inorganic solid materials. The materials were used as catalyst in the Claisen–Schmidt preparation of chalcones for the reaction of substituted acetophenones and benzaldehydes under solvent-free conditions. The result showed that the presence of a high amount of aminopropyl groups was important for a very good performance of the catalyst in the substrate conversion. Also, the influence of different groups in the aromatic ring of acetophenones and benzaldehydes was investigated. In all cases, coproduct formation was not observed; the catalysts were recovered and can be recycled twice without appreciable loss of reactivity. [Copyright &y& Elsevier]

Abstract: High temperature inorganic membranes may play an important role in the development of economical processes for pre-combustion and/or post-combustion CO2 capture. The CO2/N2 selectivity of mesoporous silica membranes is enhanced by surface modification using APTS (3-aminopropyl-triethoxy silane). Unmodified silica membranes exhibit Knudsen diffusion behavior for most gases but also have some contribution from surface diffusion of heavier or interacting gases like CO2, CH4, etc. Gas separation experiments were performed on the modified membranes for both pure gas and mixed gases for a range of temperatures and feed gas compositions. Mixed gas separation factors as high as 10 for CO2 over N2 were observed at 393K and CO2 partial pressures of 15kPa; whereas for pure gases (CO2 partial pressure of 303kPa), no separation was seen. The hypothesized transport mechanism is the reaction of CO2 with surface amine groups to form a carbamate species and subsequent surface “hopping” of carbon dioxide. The CO2 binding at ambient conditions is sufficiently strong to greatly inhibit the surface diffusion of CO2, however, as the temperature increases, the CO2 permeance increases and selective transport of CO2 is observed. The permeance of CO2 is highly non-linear, and increases with decreasing CO2 partial pressure in the feed gas. NMR studies performed on the bare support and modified membrane shows the support has been modified by APTS. Pore size analysis on the unmodified and modified silica substrates show that the pore diameter of modified substrates are lower than that of the unmodified substrate indicating that the amine silanes are anchored on the pore walls of the substrate. The NMR measurement for an APTS/silica membrane with adsorbed CO2 shows the presence of a carbamate species and thus supports the hypothesized reaction mechanism or facilitated solid-state CO2 transport. The binding energy for CO2 adsorption is 15.5kcal/mol and activation energy for CO2 diffusion/hopping from one amine group to another of APTS is 7.2kcal/mol as computed using ab initio Density Functional Theory (DFT). [Copyright &y& Elsevier]

The formation of hydroxyapatite is important for artificial materials to show high biological affinities for bone tissue. The present study focused on the synthesis of hydrogels capable of showing apatite formation, through modification of polyglutamic acid (PGA) with 3-aminopropyltriethoxysilane (APTES), followed by treatment with calcium chloride solution. A transparent bulk hydrogel was obtained at a molar ratio of PGA/APTES of 0.5. Prior soaking of the PGA hydrogel in calcium chloride solution accelerated the formation of bone-like apatite in a simulated body fluid. The modified PGA hydrogel is a candidate material for a biodegradable scaffold for bone regeneration. [ABSTRACT FROM AUTHOR]

Abstract: This study investigated the interference elimination ability of a glucose sensor made of polysilicon wire (PSW) with a surface modified by 3-aminopropyltriethoxysilane mixed with polydimethylsiloxane-treated hydrophobic fumed silica nanoparticles plus ultra-violet illumination (γ-APTES+NPs+UV). Glucose sensing of the PSW sensor in the presence of five common interferences such as ascorbic acid (AA), uric acid (UA), acetaminophen (AP), l-cysteine (Lys), and citric acid (CA) was performed. We found that the disturbance caused by the interferences was low for interference-to-glucose concentration ratios up to 600:1 if the PSW surface is modified with γ-APTES+NPs+UV. The outstanding interference immunity of this PSW glucose sensor is believed to be mainly due to the fact that it is a dry-type sensor and the extremely low leakage of the γ-APTES+NPs membrane which allows the PSW to show three orders of magnitude lower leakage current than with the γ-APTES membrane only. In addition to its excellent interference immunity, the PSW glucose sensor with a line width of 100nm also exhibits a wide linear detection range, an ultra-high sensitivity, an ultra low detection limit, and it can be reused more than a thousand times without much sensitivity degradation. [ABSTRACT FROM AUTHOR]

Abstract: 3-Aminopropyltriethoxysilane modified mesoporous SBA-15 was used to load the NiBr2(PPh3)2 as a heterogeneous catalyst for the atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) when initiated by ethyl 2-bromoisobutyrate (EBriB) in toluene. Due to the Lewis acid sites formed by the surface silanol groups of the mesoporous material, some monomer conversions were much higher even than that catalyzed by the homogeneous catalyst NiBr2(PPh3)2 under the same reaction conditions while polydispersity indices (PDI) of the products still kept narrow (1.20–1.30). At the same time, the activity of the catalyst could be modulated by changing the quantity of the –NH2, SBA-15 and the free PPh3. In the recycling experiments, the recovered heterogeneous catalyst basically maintained its catalytic activity without any addition of new heterogeneous catalyst. [ABSTRACT FROM AUTHOR]

Abstract: The grafting reactions between 3-aminopropyltriethoxysilane and Al13-intercalated/Al-pillared montmorillonites thermally pretreated at different temperatures were investigated by using X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, elemental analysis and nitrogen adsorption–desorption isotherms. The porous structures and the grafting degree of the organosilane modified Al13-intercalated/Al-pillared montmorillonite products are significantly affected by the solvents. The product prepared in anhydrous ethanol has high specific surface area (~160m2 g−1) and larger porous volume (0.134cm3 g−1) but low degree of grafting modification, while the one prepared in cyclohexane has a high loading amount of silane (2.02mmolg−1) but low surface area (7m2 g−1). Thermal treatment affects the grafting process by both reducing the water content in the interlayer space of the pillared montmorillonite and causing the transformation of the interlayer Al compounds from polycations to oxides. The hydrolyzed 3-aminopropyltriethoxysilane is mainly grafted onto the surface of the interlayer Al Keggin ions and/or Al oxides. This study demonstrates the functionalization of pillared clay to form inorganic–organic hybrid material that combines the high porosity of inorganic pillared clay and the lipophilicity of organoclay by adjusting the solvents and the pretreatment conditions, enabling potential applications in adsorption and environmental restoration. [ABSTRACT FROM AUTHOR]

Flexible polyurethane (PU) foams are easily ignitable and show a high burning velocity, mainly due to their high surface area-to-mass ratio and high air permeability. Consequently, flame retardants such as halogenated compounds are applied. However, the use of halogenated flame retardants is not considered beneficial in transport applications, for example, aviation or automobile, in part due to the high smoke generation. Solid nonhalogenated flame retardants, for example, aluminum trihydroxide (ATH), are known as smoke suppressants. The application of ATH in flexible (PU) foam has not yet been reported in the literature. In this study, the application of different types and amounts of ATH and the resulting structure-property relationship in the foam are investigated. The increase in the viscosity of the filled raw materials during the foaming process and the negative effects of the filler on the mechanical properties of the final foam pose particular problems in the application of ATH. To pass the FMVSS 302 test, high amounts of ATH are necessary. To overcome the mentioned drawbacks, ATH particles are functionalized by 3-aminopropyltriethoxysilane under different conditions. The synthesized products were characterized by Fourier transform infrared, energy-dispersive X-ray fluorescence analysis, and 29Si and ¹H solid-state nuclear magnetic resonance spectroscopy. The silane-treated ATH particles show a significant decrease in viscosity of the ATH-polyol system of more than 20% at ATH contents of up to 60 phpp. Values of the rising behavior during foaming and the burning velocity are not affected by this silane treatment. However, the compression test of PU foams with the silane-treated ATH particles show a decrease in compression strength of up to 20% compared to untreated ATH particles in the flexible PU foam. At higher ATH contents, no effect of silanization is observed. [ABSTRACT FROM AUTHOR]

New composite coatings were prepared by mixing pre-hydrolyzed methyltriethoxysilane (MTES) sol by an acidic catalyst dibutyltin dilaurate (DBTDL) and polymethylhydrosiloxane (PMHS) in gasoline at room temperature. The gel process was thoroughly investigated regarding the use of different basic catalyst [3-aminopropyltriethoxysilane (APTES) or triethylamine (TEA)], as well as the ratios of pre-hydrolyzed MTES sol and PMHS with various content of active H. It was revealed that the composite coating from 2:1 ratio (w/w) of pre-hydrolyzed MTES sol with equimolar amounts of water and PMHS1.55 under the catalysis of APTES demonstrated high pencil hardness, and excellent resistance against contamination and corrosion. This composite coating (MTPM21-A) was further characterized by FTIR, 29Si NMR, DSC and TGA. [ABSTRACT FROM AUTHOR]

Abstract: Homogeneous acid-doped polysiloxane (PS) electrolyte membranes were prepared by the sol–gel reaction from 3-aminopropyltriethoxysilane (APTES) and different acids, such as sulfuric acid (SA), methanesulfonic acid (MSA), ethanesulfonic acid (ESA), and 1-propanesulfonic acid (PSA). The effect of the acidity as well as the structure on the proton transport has been investigated. The interaction between the acid and the basic nitrogen of PS made by APTES has been confirmed by FT-IR and ab initio calculation. The thermal stability depends on the stability of the doping acid. The structure of acid-doped PS was determined by X-ray diffraction pattern and changed with the kind of acid as well as the doping amount. The proton conductivity of annealed (1:1) PS/SA membrane having high acidity as well as the hexagonal-like structure reached 1.1×10−3 S/cm at 120°C under no (or low) humidity, which is more than one order of magnitude higher than those of PS/acid membranes without structure. The structural effect was studied by PS/ESA membrane having different structure with the amount of acid doping. The proton conductivity of (3:1) PS/ESA membrane showing hexagonal-like structure is 3.82×10−4 S/cm, whereas it is 9.6×10−6 S/cm at 120°C for amorphous (1:1) PS/ESA membrane. This result implies that the main requirements for high proton transport of electrolyte membranes prepared by acid–base interaction under low humidity are the acidity and the proton transport structure. If the acidity is fixed, then the presence of the ionic channel structure is essential to design the electrolyte membrane having high proton conductivity. [Copyright &y& Elsevier]

Abstract: Functionalization of Brazilian São Simão kaolinite and Spanish Yunclillos saponite with the alkoxysilanes 3-aminopropyltriethoxysilane and 3-mercaptopropyltrimethoxysilane is reported. The resulting hybrids were characterized by X-ray diffraction, thermal analysis, infrared absorption spectroscopy, and scanning electron microscopy, which demonstrated the effectiveness of the interlamellar grafting process. The X-ray diffractograms revealed incorporation of the alkoxide molecules into the interlayer space of the clays. The displacement of the stretching bands of interlayer hydroxyls in the infrared spectra of the modified kaolinites and the increased intensity of the Mg–OH vibrations in the spectra of the modified saponites confirmed the functionalization of the clays. The thermal behavior of the organoclays confirmed the stability of the hybrids, which was dependent on the clay used for preparation of the materials. [Copyright &y& Elsevier]

Abstract: A monolayer film of 3-aminopropyltriethoxysilane (γ-APS) was prepared by contact printing with featureless PDMS stamp. First, γ-APS ink solutions in dry toluene were prepared in a dry nitrogen-filled glove box and immediately used for spin coating onto a PDMS stamp, followed by printing on a silicon wafer. Next, water contact angles and film thicknesses were measured as a function of ink concentration (5–100mM) and printing time (1–60min) after printing, as well as after aging in toluene for 24h. In addition, surface coverage, topology, RMS roughness and surface amine density were also evaluated, while the chemical structure of γ-APS monolayer was analyzed by FT-IR/ATR. Optimum conditions for γ-APS monolayer with complete coverage were determined to be ink concentration of 20mM and printing time of 30min, which resulted in a water contact angle of 93°, film thickness of 0.78nm and surface amine density of 7.6molecules/nm2. [Copyright &y& Elsevier]

A new series of Cu(II), Ni(II), and Co(II) complexes have been synthesized from 3-formylchromoniminopropylsilatrane (C19H24O5N2Si) (2) and 3-formylchromoniminopropyltriethoxysilane (1). Silatrane ligand (C19H24O5N2Si) (2) has been synthesized by the reaction between 3-aminopropyltriethoxysilane and 3-formylchromone followed by a treatment with triethanolamine. The nature of bonding and the geometry of the complexes have been deduced from elemental analyses, magnetic susceptibility, infrared, electronic, 1H NMR, 13C NMR, and ESR spectral studies. The electronic absorption spectra and magnetic susceptibility measurements of the complexes indicate square planar geometry for Cu(II) and Ni(II) and tetrahedral geometry for Co(II). The redox behavior of copper complexes was studied by cyclic voltammetry. The biological activity of the ligand and metal complexes has been studied on Klebsiella pneumoniae, Staphylococcus aureus, Escherichia Coli, and Bacillus subtilis by the well diffusion method using acetonitrile as solvent. The zone of inhibition values were measured at 37°C for 24 h. Antimicrobial screening tests show better results for the metal complexes than the ligand. [ABSTRACT FROM AUTHOR]

3-aminopropyltriethoxysilane grafted montmorillonites were synthesized with montmorillonite, acid-activated montmorillonites and 3-aminopropyltriethoxysilane in ethanol-water mixture. The resulting products were investigated using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TG). XRD patterns demonstrated that silane was intercalated into the montmorillonite gallery, indicated by increasing basal spacings. These intercalated silanes probably adopt bilayer arrangement models within the montmorillonite and acid-activated montmorilloflites interlayer spaces. TG and DTG curves indicate that acidification results in a decrease of the thermal stability of the resultant montmorillonites. Silane grafting leads to a surface property transformation of montmorillonite from hydrophilicity to lipophilicity and an increase of the thermal stability of the condensed silanes. [ABSTRACT FROM AUTHOR]

Abstract: Amino-functionalized organic films were prepared by self-assembling 3-aminopropyltriethoxysilane (APTES) on silicon wafers in either anhydrous toluene or phosphate-buffered saline (PBS) for varied deposition times. Fourier transform infrared spectroscopy (FTIR) and ellipsometry have shown that the structure and thickness of APTES films are governed by the deposition time and reaction solution. Deposition from an anhydrous toluene solution produces APTES films ranging from 10 to 144 Å in thickness, depending on the reaction time. FTIR spectra indicate that film growth initially proceeds by adsorption of APTES to the silicon surface followed by siloxane condensation, and after an extended period of time APTES molecules accumulate on the underlying APTES film by either covalent or noncovalent interactions. In contrast, spectroscopically indistinguishable APTES films in thickness ranging from 8 to 13 Å were formed when deposition was conducted in aqueous solutions. Measured water contact angles indicate that APTES films deposited in aqueous solutions are more hydrophilic compared to those prepared in toluene solutions. Fluorescence measurements revealed that APTES films prepared in toluene solutions contain more reactive surface amino groups by ca. 3 to 10 times than those prepared in aqueous solutions for the identical reaction time. [Copyright &y& Elsevier]

Abstract: The effect of curing on the structure and stability of amino-functionalized organic films on silicon substrates was investigated using Fourier transform infrared spectroscopy (FTIR), ellipsometry, and fluorescence microscopy. Amino-terminated organic films were prepared on silicon wafers by self-assembling 3-aminopropyltriethoxysilane (APTES) in toluene, cured at different conditions, and washed by sonication in water. For APTES films without curing/or cured at 25°C, the thickness of APTES films decreased by as much as 65% after sonication in water. FTIR spectra indicate that a substantial amount of physisorbed and/or partially condensed APTES was removed and surface amino groups were oxidized to imines. For APTES films cured at 100°C, ellipsometric measurements and FTIR spectra showed that the thickness was decreased by ∼10% and that remaining loosely bound APTES had become condensed after curing. Further sonication in water caused no significant changes in the thickness and structure. Independent fluorescence measurements support ellipsometric results and FTIR studies. Our investigations suggest that freshly prepared APTES films are mechanically unstable in aqueous solutions and that proper curing process is required to form physically stable APTES films. [Copyright &y& Elsevier]

Abstract: Proton conductive inorganic–organic hybrid membranes with acid–base pairs have been prepared from 3-aminopropyltriethoxysilane and phosphoric acid by the sol–gel method. The self-standing membranes obtained are represented as poly(3-aminopropylsilsesquioxane)-H3PO4 (PAPS–H3PO4) membranes. Infrared absorption spectra of the PAPS–H3PO4 films showed that amino groups of PAPS were protonated by phosphoric acid, indicating the formation of acid–base pairs. X-ray diffraction patterns of the PAPS–H3PO4 membranes showed diffraction peaks attributed to hexagonal structure, which is probably formed by stacking of rodlike polysiloxane with the acid–base pairs extruded outside. The conductivities of the PAPS–H3PO4 membranes with a molar ratio of H3PO4/APTES=1.0 was 4×10−4 S cm−1 at 150 °C under dry condition. [Copyright &y& Elsevier]

Abstract: This work shows an alternative process for β-ketoester transesterification using new silica-based hybrid materials as heterogeneous catalysts. The catalysts were synthesized using silica and 3-aminopropyltriethoxysilane or 1,1,1,3,3,3-hexamethyldisilazane as functionalizating agents. β-Ketoesters and alcohols were transesterified in refluxing toluene with reaction times between 4h and 14h. Different ketoesters with good performance were obtained. The influence of the catalysts and starting materials on the reaction rate was studied. In all cases, coproduct formation was not observed; the catalysts were recovered and reused without loss of catalytic activity. [Copyright &y& Elsevier]

Surface modification of clay minerals has become increasingly important for improving the practical applications of clays such as fillers and adsorbents. An investigation was carried out on the surface modification of sepiolite with aminopropylsilyl groups in 3-aminopropyltriethoxysilane (3-APT). The zeta potential of the modified sepiolite suspensions was measured as a function of initial electrolyte concentration and equilibrium pH using a Zeta Meter 3.0 for modified sepiolite. The utility of the 3-APT-modified sepiolite was investigated as an adsorbent for removal of various heavy metal ions such as Fe, Mn, Co, Zn, Cu, Cd and Ni from aqueous solutions. The effects of various factors on the adsorption, such as pH, ionic strength and temperature of the solution were studied. The results showed that the amount adsorbed increases with solution pH in the pH range of 1.5 and 7.0; indicated that the modified sepiolite adsorbed Fe and Mn ions more than other metal ions such as Co, Zn, Cu, Cd and Ni. It was found that the temperature had an important effect on metal ion adsorption by the modified sepiolite. The adsorption isotherm has been determined and data have been analyzed according to the Langmuir and Freundlich models. [Copyright &y& Elsevier]

In this work a ‘carrier’ was selected that would separate an anionic reactive dye from aqueous solution, and would display an intense white colour and a high adsorptive capacity. In this context, a commercial, highly dispersed precipitate, Syloid® 244 silica was employed to remove C.I. Reactive Blue 19. The adsorption resulted in blue pigmentation of the silica carrier; the ensuing pigment was subjected to a comprehensive physicochemical analysis, including particle size, particle size distribution, polydispersity, tendency to form primary and secondary agglomerates and the morphology of the particle surface. It was found that a preliminary surface modification of the silica adsorbent with an NH2-silane compound was necessary. The aminosilane-modified silica could be used as a selective adsorbent in the purification of waste dye solutions; its application secured highly efficient removal of dye from solutions (in most cases over 90% and in some cases even 100%). The silica-carrier product was then used as a pigment within an exterior acrylic paint. Optimum properties were obtained using 5% silane; the ensuing pigment displayed very low polydispersity (0.030), low mean particle diameter (428nm) and no tendency to form secondary agglomerates. [Copyright &y& Elsevier]

Abstract: Silane grafted montmorillonites were synthesized by using 3-aminopropyltriethoxysilane and trimethylchlorosilane via two different grafting reaction systems: (a) ethanol–water mixture and (b) vapor of silane. The resulting products were investigated using Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA). XRD patterns demonstrate that silane was intercalated into the montmorillonite gallery, as indicated by the increase of the basal spacing. The product prepared by vapor deposition has a larger basal spacing than that obtained from solution, due to the different extent of silane hydrolysis in various grafting systems. TGA curves indicate that the methyl groups penetrate into the siloxane clay are the primary reason for the decrease of the dehydroxylation temperature of the grafted products. 3-Aminopropyltriethoxysilane in the grafted montmorillonite adopts a bilayer arrangement while trimethylchlorosilane adopts a monolayer arrangement within the clay gallery. [Copyright &y& Elsevier]

Abstract: We have prepared novel proton conducting inorganic–organic hybrid membranes from 3-aminopropyltriethoxysilane (APTES) and H2SO4 by the sol–gel method. The resulting poly(3-aminopropylsilsesquioxane sulfate or hydrogensulfate) (PAPS-SO4/-HSO4) membranes were thermally stable up to 300 °C. From the results of IR spectra, it was confirmed that sulfuric acids in the membranes react with amino groups of PAPS to form ion complexes. XRD patterns of the PAPS-SO4/-HSO4 membranes showed diffraction peaks assigned to hexagonal structure, which is probably formed by stacking of rodlike polysiloxanes with the ion complexes extruded outside. The PAPS-SO4/-HSO4 membranes with a molar ratio of H2SO4/APTES=1.0 showed high proton conductivities of 2×10− 3 S cm− 1 at 200 °C under dry condition. [Copyright &y& Elsevier]

A study has been conducted on the effects of surface pretreatment with 3-aminopropyltriethoxysilane (3-APS) on the water absorption and adhesion behaviour on mild steel and glass substrates of two commercial organic coatings, one an alkyd coating and the other a two pack epoxypolyamide coating. The results have shown that using 3-APS for surface pretreatment before coating results in a significant reduction of total water absorption for both coating systems on a glass substrate. However, for the mild steel substrate, treatment with 3-APS reduces water absorption using an alkyd system, but increases it in the epoxy system. The results also indicate that using 3-APS for pretreatment enhances the overall wet adhesion performance for alkyd coatings on steel and epoxy and alkyd coatings on glass substrates but not for epoxy on steel. These data are consistent with the known adsorption behaviour of 3-APS on steel, i.e. as an easily hydrolysed hydrogen bond to the amine group, rather than as the more stable metal–oxide–silicon bond. [ABSTRACT FROM AUTHOR]

Abstract: Functionalization of montmorillonite clay has been done using 3-aminopropyltriethoxysilane in the presence of various solvent media. Qualitative evidence of the presence of aminosilane attached to the clay platelets have been identified using Fourier transform infrared spectroscopy (FTIR) and 29Si and 13C solid-state nuclear magnetic resonance (NMR) spectroscopy. Grafting yield has been calculated using thermogravimetric analysis and total grafting yield increases with the solvent surface energy. X-ray diffraction studies of the silane functionalized montmorillonite clay exhibits two peaks, which may be attributed to intercalation and surface interaction with the broken edge platelets. Functionalized clay has been characterized by surface area measurements to understand the influence of solvents on the surface area of the functionalized clay. [Copyright &y& Elsevier]

Abstract: The aim of this study was to investigate rubber toughening of resol type phenol–formaldehyde resin. For this purpose, phenolic resin was first modified by acrylonitrile butadiene rubber alone, and then by using nitrile rubber together with 3-aminopropyltriethoxysilane. Test specimens were prepared by mixing and casting of liquid phenolic resin in three groups. In the first one, neat phenolic resin specimens were produced. In the second group, phenolic resin was modified with 0.5, 1, 2, and 3wt% nitrile rubber, while in the last group modification was carried out by using 0.5wt% nitrile rubber together with 1, 2, and 4wt% amino silane (with respect to nitrile rubber). All specimens were heat cured in an oven. In order to observe behavior of the specimens, three-point bending, Charpy impact, plane-strain fracture toughness, and dynamic mechanical analysis tests were conducted according to the related ISO standards for all specimen groups. Scanning electron microscopy (SEM) was also used for the fractographic analysis of some samples. It was concluded that although there were problems in mixing and casting of liquid resol type phenolic resin, its toughness could be improved by using nitrile rubber and amino silane. Modification by using nitrile rubber and amino silane together was much more effective than by using only nitrile rubber. For instance, in this synergistic case Charpy impact strength and fracture toughness values of the neat phenolic specimens were increased 63 and 50%, respectively. SEM studies indicated that the main rubber toughening mechanism was shear yielding observed as deformation lines, especially initiated at the domains of nitrile rubber and amino silane. [Copyright &y& Elsevier]

Abstract: New sol–gel encapsulated glucose oxidase (GOx) enzyme electrodes, constructed from carbon film resistor electrodes and chemically deposited copper hexacyanoferrate as mediator, have been developed and characterized using cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The sol–gel was prepared using three different oxysilanes: 3-aminopropyltriethoxysilane (APTOS), 3-glycidoxypropyltrimethoxysilane (GOPMOS) and the well-known tetraethoxysilane (TEOS). The sol–gel composition was optimised for each oxysilane according to the gelation time of the sol–gel solution and response time of the enzyme biosensor to standard additions of glucose. Results obtained showed that APTOS and GOPMOS have similar electrochemical behaviour but differ from TEOS. As a glucose biosensor, the sensitivity can be described by the sequence: GOPMOS>APTOS>TEOS with detection limits down to 44μM. The sensor lifetime was improved by elimination of ethanol from the hydrolysed oxysilanes by heating in a hot air stream after which APTOS-based sensors showed superior properties to GOPMOS, but with higher detection limit, and were sufficiently stable to be used for over several weeks. [Copyright &y& Elsevier]

Abstract: The grafting reaction between a trifunctional silylating agent and two kinds of 2:1 type layered silicates was studied using FTIR, XRD, TGA, and 29Si CP/MAS NMR. XRD patterns clearly indicate the introduction of 3-aminopropyltriethoxysilane (γ-APS) into the clay interlayer. In the natural montmorillonite, γ-APS adopts a parallel-bilayer arrangement, while it adopts a parallel-monolayer arrangement in the synthetic fluorohectorite. These different silane arrangements have a prominent effect on the mechanism of the condensation reaction within the clay gallery. In natural montmorillonite, the parallel-bilayer arrangement of γ-APS results in bidentate (T2) and tridendate (T3) molecular environments, while the parallel-monolayer arrangement leads to monodentate (T1), as indicated by 29Si CP/MAS NMR spectra. This study demonstrates that the silylation reaction and the interlayer microstructure of the grafting products strongly depend on the original clay materials. [Copyright &y& Elsevier]

We used different methods to modify a mica surface with 3-aminopropyltriethoxysilane (APTES), and then used it as substrate to immobilize DNA for atomic force microscopy (AFM) observation. The evaporation method and solution modifying method were investigated and evaluated. The solution modifying method was found to be relatively simple and effective. Using an APTES solution-modified mica surface, DNA immobilization appeared more reproducible and it could be imaged in liquid. The mixed solution of APTES and DNA was dropped directly onto the mica surface for AFM imaging. We found that DNA can condense in APTES water solutions. Toroids, rods and intermediate structures of condensation were captured by AFM. [ABSTRACT FROM AUTHOR]

H-kenyaite was modified by interlayer surface silylation using 3-aminopropyltriethoxysilane and dodecylamine in ethanol without a pre-swelling step. Dodecylamine acts as a gallery expander and silylation catalyst. The evaporation of ethanol from the dispersion yields well-ordered silylated kenyaites with large basal spacings between 4.12 and 5.12 nm. Solid-state 29Si MAS NMR of the silylated samples showed Q3 and Q4 signals as well as T2 and T3 signals. The increase in the relative intensity of Q4 for Q3 and the appearance of T2 and T3 signals was attributed to the grafting of 3-aminopropyltriethoxysilane to the interlayer surface silanol groups. [Copyright &y& Elsevier]

A series of polyimide (PI)-silica hybrid nanocomposites are prepared from 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA)-4,4'-oxydianiline (ODA) polyamic acid (PAA) and tetraethoxysilane (TEOS) or tetramethoxysilane (TMOS) by the sol-gel process. 3-Aminopropyltriethoxysilane (3-APS) is used to enhance the interfacial interaction between polyimide and silica. The morphology, interfacial interaction, and properties of the hybrids are investigated using scanning electron microscope (SEM), UV-vis spectroscopy, atomic force microscope (AFM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). SEM and AFM images indicate that silica particles of ca. 45-55 nm size are uniformly distributed in polyimide matrices and that the interfacial interaction between PI and TEOS is better than that between PI and TMOS. The optical transparencies of the PI/TEOS hybrids are better than that of the PI/TMOS hybrids. FTIR spectra confirm the Si--O--Si bond as well as the conversion of PAA to polyimide and PI/silica hybrid films. The thermal stability is increased after incorporation of the silicas in the polyimide matrix. [ABSTRACT FROM AUTHOR]

The polymerization behavior of 3-aminopropyltriethoxysilane, a process initiated by water molecules, has been examined using time-resolved near-IR and 2D near-IR correlation spectra. By deconvolution of the time-resolved near-IR spectra, the existence of the component bands at 5189, 5265 and 5300 cm−1, whose intensities decrease markedly as the reaction proceeds, has been confirmed in the 5000–5400 cm−1 region. The band at 5189 cm−1 has been assigned to water molecules, while those at 5265 and 5300 cm−1 have been assigned to the strongly and weakly associated silanol groups, respectively. The kinetics of the hydrolysis of the ethoxy groups and of the formation of a siloxane bond have been analyzed using the time-dependent integral intensities of these three bands and the mechanisms of the reactions have been discussed. Evidence for this polymerization process is also clearly evident in the 2D near-IR correlation spectra. [ABSTRACT FROM AUTHOR]

[Display omitted] • High quality Bi nanosheets (NS) are in-situ prepared on carbon paper by electro reduction. • 3-Aminopropyltriethoxysilane (APTES)/Bi-NS highly efficient for CO 2 conversion to HCOOH. • APTES/Bi-NS beneficial to formation of intermediates *OCHO to formate. • DFT calculation proves the decrease in energy barrier of OCHO*to HCOOH over APTES/Bi-NS. Herein, the effects of the introduction of 3-aminopropyltriethoxysilane (APTES) on the intrinsic properties of functionalized Bi nanosheets (Bi-NHS) electrocatalyst and the electrocatalytic performance of CO 2 reduction reaction were carefully studied. As a result, high selectivities (> 90 %) to formate in significantly wide potentials of 500 mV and the energy efficiency Φ HCOOH as high as 65.8 % at –0.66 V for the cathodic half reaction can be observed. In addition, the Bi-NHS electrode shows a maximal faradic efficiency of 96.0 % at –0.96 V and a low overpotential around 340 mV, maintains well-preserved catalytic activity, giving formate yield of 8.02 g L−1, in a long term of continuous electrolysis. Based on experiment and density functional theory (DFT) calculations, CO 2 reduction to formate on Bi(001)-NHS surface is more energetically favorable than that on bare Bi(001) surface and the APTES is excellent ligands as promoters for stabilized catalytic performance of metallic bismuth. [ABSTRACT FROM AUTHOR]

This paper describes the effect of calcination temperature on the phase composition, chemical composition, and morphology of ZrO2 and Al2O3 powders modified with 3-aminopropyltriethoxysilane (APTES). Both ceramic powders were modified by etching in piranha solution, neutralization in ammonia water, reaction with APTES, ultrasonication, and finally calcination at 250, 350, or 450 °C. The obtained modified powders were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, particle size distribution (PSD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS), and thermogravimetric analysis (TGA). [ABSTRACT FROM AUTHOR]

Chitosan crosslinked with 3-aminopropyltriethoxysilane was coated on porous poly (L-lactic acid) nanofibrous membrane to remove dyes from wastewater in the present study. The adsorption capacity of the composite membrane for the removal of methylene blue and rhodamine B was comprehensively studied. Large porous framework provided a high surface area to effectively immobilize the cross-linked chitosan on nanofibrous membranes. Batch trials were performed to evaluate the adsorption behaviour of membranes with variable crosslinking ratio, pH, initial concentration, temperature and time. Moreover, the adsorbent membranes before and after adsorption were characterized using scanning electron microscopy, x-ray energy dispersive analysis, and Fourier transform infrared spectrophotometer. Under optimum parameters, the adsorbent showed the removal capacity of 86.43 and 82.37 mg/g for rhodamine B and methylene blue, respectively. Isothermal and kinetic experiments showed that Langmuir isotherm and pseudo second order kinetics correlated best with adsorption data. Finally, the mechanism of adsorption and reusability of membrane for five cycles was studied. [Display omitted] • Successful crosslinking of chitosan with 3-aminopropyltriethoxysilane. • Immobilization of crosslinked chitosan on porous poly (l-lactic acid) nanofibers. • Study of adsorption isotherms and kinetics. • Faster and higher adsorption of methylene blue and rhodamine B dyes. • Reusability of adsorbent membranes. [ABSTRACT FROM AUTHOR]

An aminolysis mechanism is proposed to explain the enhanced adhesion between the interface of a bisphenol-A polycarbonate substrate with an alkoxysilane containing sol-gel coating when 3-aminopropyltriethoxysilane (3-APS) is used as a primer. Both a model solution study and surface analyses of polycarbonate substrates exposed to 3-APS indicate that the latter reacts with the carbonate groups in the polycarbonate chain by forming urethane linkages. With 3-APS bonded to the substrate, a sol-gel coating can be chemically bonded to the substrate through hydrolysis of alkoxysilane groups and subsequent silanol condensation. Consequently, enhanced adhesion between the sol-gel coating and the substrate is achieved. [ABSTRACT FROM AUTHOR]

The unique sol/gel behavior of an organic/inorganic hybrid material synthesized from 3-aminopropyl-triethoxysilane (3AS) and tetramethoxysilane (TMOS) is discussed and examined. The addition of H2O to a mixture of a basic (3AS) and an acidic (TMOS) alkoxide leads to rapid gel formation. This wet gel reverses to a sol upon heating which is attributed to the dissolution of siloxane bonds between the surfaces of colloidal particles in the gel. The reversed sol dries to an optically transparent solid which is water soluble. The water solubility and the stability of these colloidal particles are described by their aminopropyl/silanol surface and the electrostatic interactions between them using DLVO theory. [ABSTRACT FROM AUTHOR]

[Display omitted] • Highly dispersed catalysts were prepared by pre-modification with minimal 3-aminopropyltriethoxysilane and impregnation method. • Modified catalysts with lower Pd loading exhibited excellent hydrogenation performance compared with the commercial catalyst. • Modification of excessive 3-aminopropyltriethoxysilane will result in the decrease in metal dispersion for the intense anchoring sites. • The catalyst having the molar ratio of APTES /Pd = 2 with 0.2 wt% Pd showed the highest catalytic activity and selectivity. Faced with the problems of poor activity and inferior selectivity, highly dispersed Pd catalysts pre-modified by minimal 3-aminopropyltriethoxysilane (APTES) were prepared via impregnation reduction method. The amount of APTES was adjusted according to molar ratios of the APTES to Pd (APTES/Pd). The catalytic hydrogenation efficiency exhibited a volcano-shape trend with the amount of APTES. Grafting of suitable amount of APTES improved the dispersion of the Pd, increased the weak acid content of the γ-Al 2 O 3 and regulated the reducibility of the catalysts. The catalyst having APTES/Pd = 2 with 0.192 wt% Pd showed the highest catalytic activity and selectivity, with 100 % in the selectivity and the improvement of 27.3 % in the hydrogenation efficiency and 104.8 % in the H 2 O 2 productivity compared with the commercial catalyst (0.298 wt%). Furthermore, the APTES aggregated with the amount of APTES, which provided intense anchoring sites for the Pd and resulted in the increase in larger palladium nanoparticles. [ABSTRACT FROM AUTHOR]

● COF-1 coated capillary was fabricated via one-step synthesis and immobilization. ● APTES played a triple role of catalyst, stabilizer, and connecting arm. ● The as-developed method was applied for the immobilization of boron-based COFs. ● COF-1@capillary exhibited excellent electrochromatographic separation performance. Inspired by the outstanding functions of 3-aminopropyltriethoxysilane (APTES), which can be used for functionalization of both covalent organic frameworks (COFs) and substrate surfaces, herein, a proof-of-concept demonstration was carried out by one-step synthesis and immobilization of COF-1 in capillary. COF-1 was grown on the inner wall of capillary using APTES, which played a triple role of catalyst, stabilizer, and connecting arm during the process. The immobilization of COF-1 on silicon surface was confirmed by scanning electron microscopy. Moreover, COF-1 modified capillary (COF-1@capillary) column exhibited excellent performance in the electrochromatographic separation of amino acids. High resolution and separation efficiency (225,378 plates/m for 4-methylbiphenyl) were successfully achieved. Separation of methylbenzene, styrene, ethylbenzene, chlorobenzene, 1,2-dichlorobenzene, 1,2,4-trichlorobenzene, 4-methylbiphenyl, naphthalene, and 4-vinylbipheny in the electro-driven mode confirmed the successful growth of COF-1 on the inner wall of capillary. The developed facile method for the immobilization of COF-1 may pave the way for further application prospects of boron-based COFs. [ABSTRACT FROM AUTHOR]