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Jeffrey P Youngblood - One of the best experts on this subject based on the ideXlab platform.
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Surface Modification of Polymers with 3-Aminopropyltriethoxysilane as a General Pretreatment for Controlled Wettability
Macromolecules, 2007Co-Authors: John A. Howarter, Jeffrey P YoungbloodAbstract:Various polymer surfaces were analyzed for reactivity toward 3-Aminopropyltriethoxysilane (APTES). Results indicate that the method described here is useful as a general surface-selective modification technique for polar polymers such as polyesters, polyamides, polycarbonates, polyimides, cellulosics, polyacrylics, etc. X-ray photoelectron spectroscopy (XPS) showed an average of 10% silicon and nitrogen atomic concentrations at 75° takeoff for all successfully modified surfaces. The APTES multilayers were subsequently hydrophobized with perfluorinated chlorosilanes giving 40% fluorine atomic concentration by XPS and 120°/90° (advancing/receding) dynamic contact angle averages. APTES modifications were successful in all solvents with the exception of protic solvents. On the basis of these and other observations, a new model for the reaction pathway is proposed. We propose the reaction proceeds by initial APTES adsorption (likely through hydrogen bonding by the amine) to the substrate, lateral bond formatio...
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Optimization of silica silanization by 3-Aminopropyltriethoxysilane
Langmuir, 2006Co-Authors: John A. Howarter, Jeffrey P YoungbloodAbstract:Thin films of 3-Aminopropyltriethoxysilane (APTES) are commonly used to promote adhesion between silica substrates and organic or metallic materials with applications ranging from advanced composites to biomolecular lab-on-a-chip. Unfortunately, there is confusion as to which reaction conditions will result in consistently aminated surfaces. A wide range of conflicting experimental methods are used with researchers often assuming the creation of smooth self-assembled monolayers. A range of film morphologies based on the film deposition conditions are presented here to establish an optimized method of APTES film formation. The effect of reaction temperature, solution concentration, and reaction time on the structure and morphology was studied for the system of APTES on silica. Three basic morphologies were observed: smooth thin film, smooth thick film, and roughened thick film.
Masahiro Tatsumisago - One of the best experts on this subject based on the ideXlab platform.
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proton conductive inorganic organic hybrid membranes prepared from 3 Aminopropyltriethoxysilane and phosphoric acid by the sol gel method
Solid State Ionics, 2008Co-Authors: Teruaki Tezuka, Kiyoharu Tadanaga, Akitoshi Hayashi, Masahiro TatsumisagoAbstract: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.
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inorganic organic hybrid membranes prepared from 3 Aminopropyltriethoxysilane and sulfuric acid as anhydrous proton conductors
Solid State Ionics, 2007Co-Authors: Teruaki Tezuka, Kiyoharu Tadanaga, Akitoshi Hayashi, Masahiro TatsumisagoAbstract:Abstract We have prepared novel proton conducting inorganic–organic hybrid membranes from 3-Aminopropyltriethoxysilane (APTES) and H 2 SO 4 by the sol–gel method. The resulting poly(3-aminopropylsilsesquioxane sulfate or hydrogensulfate) (PAPS-SO 4 /-HSO 4 ) 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-SO 4 /-HSO 4 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-SO 4 /-HSO 4 membranes with a molar ratio of H 2 SO 4 /APTES = 1.0 showed high proton conductivities of 2 × 10 − 3 S cm − 1 at 200 °C under dry condition.
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Inorganic-organic hybrid membranes with anhydrous proton conduction prepared from 3-Aminopropyltriethoxysilane and sulfuric acid by the sol-gel method.
Journal of the American Chemical Society, 2006Co-Authors: Teruaki Tezuka, Kiyoharu Tadanaga, And Akitoshi Hayashi, Masahiro TatsumisagoAbstract:Inorganic−organic hybrid membranes with anhydrous proton conduction were prepared from 3-Aminopropyltriethoxysilane and H2SO4 by the sol−gel method. The membrane has a unique structure: a hexagonal phase formed by the stacking of rodlike polysiloxanes with ion complexes of ammonium groups and HSO4- extruded outside. The membranes showed high conductivity of 2 × 10-3 S cm-1 at 200 °C under dry atmosphere. In the membrane, protons probably migrate through the outside of the rodlike polysiloxanes along hydrogen-bond chains formed among HSO4- anions.
John A. Howarter - One of the best experts on this subject based on the ideXlab platform.
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Surface Modification of Polymers with 3-Aminopropyltriethoxysilane as a General Pretreatment for Controlled Wettability
Macromolecules, 2007Co-Authors: John A. Howarter, Jeffrey P YoungbloodAbstract:Various polymer surfaces were analyzed for reactivity toward 3-Aminopropyltriethoxysilane (APTES). Results indicate that the method described here is useful as a general surface-selective modification technique for polar polymers such as polyesters, polyamides, polycarbonates, polyimides, cellulosics, polyacrylics, etc. X-ray photoelectron spectroscopy (XPS) showed an average of 10% silicon and nitrogen atomic concentrations at 75° takeoff for all successfully modified surfaces. The APTES multilayers were subsequently hydrophobized with perfluorinated chlorosilanes giving 40% fluorine atomic concentration by XPS and 120°/90° (advancing/receding) dynamic contact angle averages. APTES modifications were successful in all solvents with the exception of protic solvents. On the basis of these and other observations, a new model for the reaction pathway is proposed. We propose the reaction proceeds by initial APTES adsorption (likely through hydrogen bonding by the amine) to the substrate, lateral bond formatio...
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Optimization of silica silanization by 3-Aminopropyltriethoxysilane
Langmuir, 2006Co-Authors: John A. Howarter, Jeffrey P YoungbloodAbstract:Thin films of 3-Aminopropyltriethoxysilane (APTES) are commonly used to promote adhesion between silica substrates and organic or metallic materials with applications ranging from advanced composites to biomolecular lab-on-a-chip. Unfortunately, there is confusion as to which reaction conditions will result in consistently aminated surfaces. A wide range of conflicting experimental methods are used with researchers often assuming the creation of smooth self-assembled monolayers. A range of film morphologies based on the film deposition conditions are presented here to establish an optimized method of APTES film formation. The effect of reaction temperature, solution concentration, and reaction time on the structure and morphology was studied for the system of APTES on silica. Three basic morphologies were observed: smooth thin film, smooth thick film, and roughened thick film.
Xianhua Cheng - One of the best experts on this subject based on the ideXlab platform.
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Tribological behaviors of self-assembled 3-Aminopropyltriethoxysilane films on silicon
Current Applied Physics, 2008Co-Authors: Xianhua ChengAbstract:Abstract 3-Aminopropyltriethoxysilane (APTES) thin films were prepared on the hydroxylated silicon substrate by a self-assembling process from formulated solution. Chemical compositions of the films were detected by X-ray photoelectron spectrometry (XPS). The thickness of the films was determined with an ellipsometer, while the morphologies of the original and worn surfaces of the samples were analyzed by means of atomic force microscopy (AFM) and scanning electron microscopy (SEM), respectively. The tribological properties of APTES thin films sliding against GCr15 steel ball were evaluated on a UMT-2MT reciprocating friction and wear tester. It was found that the macroscopic friction coefficients for coating times more than 1 h ranged from 0.177 to 0.3 whereas the value for short coating time was as high as 0.8. It was also found that the tribological behaviors of APTES films were sensitive to normal load and sliding velocity. SEM observation of the morphologies of worn surfaces indicates that the wear of silicon is characteristic of brittle fracture and severe abrasion. Differently, abrasion and micro-crack dominate the wear of APTES–SAM. The superior friction reduction and wear resistance of APTES films compared to the silicon substrate are attributed to good adhesion of the films to the substrate.
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Tribological behaviors of lanthanum-based phosphonate 3-Aminopropyltriethoxysilane self-assembled films
Applied Surface Science, 2007Co-Authors: Xianhua ChengAbstract:Lanthanum-based thin films deposited on the phosphonate 3-Aminopropyltriethoxysilane (APTES) self-assembled monolayer (SAM) were prepared on the hydroxylated glass substrate by a self-assembling process from specially formulated solution. Chemical compositions of the films and chemical state of the elements were detected by X-ray photoelectron spectrometry (XPS). The thickness of the films was determined with an ellipsometer, while the morphologies of the original and worn surfaces of the samples were analyzed by means of atomic force microscopy (AFM) and scanning electron microscopy (SEM), respectively. The tribological properties of the films sliding against GCr15 steel ball were evaluated on a UMT-2MT reciprocating friction and wear tester. As the results, the target film was obtained and reaction may have taken place between the film and the glass substrate. The tribological results show that lanthanum-based thin films are superior in reducing friction and resisting wear compared with APTES-SAM and phosphorylated APTES-SAM. SEM observation of the morphologies of worn surfaces indicates that the wear of APTES-SAM and the phosphorylated APTES-SAM is characteristic of brittle fracture and severe abrasion. Differently, slight abrasion and micro-crack dominate the wear of lanthanum-based thin films. The superior friction reduction and wear resistance of lanthanum-based thin films are attributed to the enhanced load-carrying capacity of the inorganic lanthanum particles in the lanthanum-based thin films as well as good adhesion of the films to the substrate.
Chang-sik Ha - One of the best experts on this subject based on the ideXlab platform.
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Microstructure and properties of polyamideimide/silica hybrids compatibilized with 3-Aminopropyltriethoxysilane
European Polymer Journal, 2008Co-Authors: Youri Ha, Myeon-cheon Choi, Chang-sik HaAbstract:In this work, we prepared and characterized polyamideimide (PAI)/silica hybrids compatibilized with 3-Aminopropyltriethoxysilane (APTES). PAI/silica nanohybrid thin films were prepared using an in situ sol–gel process, followed by thermal imidization. We have investigated the microstructures and properties of the PAI/silica hybrids using FT-IR spectroscopy, X-ray diffraction, small-angle X-ray scattering (SAXS), and differential scanning calorimetry (DSC). We also measured their tensile properties, thermal properties, refractive indices, and dielectric constants. In general, the properties of the PAI/silica hybrids were optimized when the silica content was 6 wt.%.