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Krishna Gopakumar Warrier - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of mesoporous Hydrophobic Silica microspheres through a modified sol–emulsion–gel process
Journal of Sol-Gel Science and Technology, 2008Co-Authors: S. Smitha, P. Shajesh, P. Mukundan, Krishna Gopakumar WarrierAbstract:Mesoporous Silica microspheres were synthesised through a sol–emulsion–gel process using Span 80 as the surfactant in Silica sol/n-hexane water in oil emulsion system. Surface modification of the microspheres was done with trimethylchlorosilane to obtain Hydrophobic Silica microspheres. Various parameters related to the synthesis of microspheres, including concentration of surfactant and viscosities of sol were studied. The Hydrophobicity (wettability), thermal stability, porosity, and morphological features were also investigated.
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synthesis of biocompatible Hydrophobic Silica gelatin nano hybrid by sol gel process
Colloids and Surfaces B: Biointerfaces, 2007Co-Authors: S. Smitha, P. Shajesh, P. Mukundan, T.d.r. Nair, Krishna Gopakumar WarrierAbstract:Abstract Silica–biopolymer hybrid has been synthesised using colloidal Silica as the precursor for Silica and gelatin as the biopolymer counterpart. The surface modification of the hybrid material has been done with methyltrimethoxysilane leading to the formation of biocompatible Hydrophobic Silica–gelatin hybrid. Here we are reporting Hydrophobic Silica–gelatin hybrid and coating precursor for the first time. The hybrid gel has been evaluated for chemical modification, thermal degradation, Hydrophobicity, particle size, transparency under the UV–visible region and morphology. FTIR spectroscopy has been used to verify the presence of CH 3 groups which introduce Hydrophobicity to the SiO 2 –MTMS–gelatin hybrids. The Hydrophobic property has also been tailored by varying the concentration of methyltrimethoxysilane. Contact angle by Wilhelmy plate method of transparent Hydrophobic Silica–gelatin coatings has been found to be as high as ∼95°. Oxidation of the organic group which induces the Hydrophobic character occurs at 530 °C which indicates that the surface Hydrophobicity is retained up to that temperature. Optical transmittance of SiO 2 –MTMS–gelatin hybrid coatings on glass substrates has been found to be close to 100% which will enable the hybrid for possible optical applications and also for preparation of transparent biocompatible Hydrophobic coatings on biological substrates such as leather.
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Synthesis of biocompatible Hydrophobic Silica-gelatin nano-hybrid by sol-gel process.
Colloids and surfaces. B Biointerfaces, 2006Co-Authors: S. Smitha, P. Shajesh, P. Mukundan, T.d.r. Nair, Krishna Gopakumar WarrierAbstract:Silica-biopolymer hybrid has been synthesised using colloidal Silica as the precursor for Silica and gelatin as the biopolymer counterpart. The surface modification of the hybrid material has been done with methyltrimethoxysilane leading to the formation of biocompatible Hydrophobic Silica-gelatin hybrid. Here we are reporting Hydrophobic Silica-gelatin hybrid and coating precursor for the first time. The hybrid gel has been evaluated for chemical modification, thermal degradation, Hydrophobicity, particle size, transparency under the UV-visible region and morphology. FTIR spectroscopy has been used to verify the presence of CH(3) groups which introduce Hydrophobicity to the SiO2-MTMS-gelatin hybrids. The Hydrophobic property has also been tailored by varying the concentration of methyltrimethoxysilane. Contact angle by Wilhelmy plate method of transparent Hydrophobic Silica-gelatin coatings has been found to be as high as approximately 95 degrees . Oxidation of the organic group which induces the Hydrophobic character occurs at 530 degrees C which indicates that the surface Hydrophobicity is retained up to that temperature. Optical transmittance of SiO2-MTMS-gelatin hybrid coatings on glass substrates has been found to be close to 100% which will enable the hybrid for possible optical applications and also for preparation of transparent biocompatible Hydrophobic coatings on biological substrates such as leather.
S. Smitha - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of mesoporous Hydrophobic Silica microspheres through a modified sol–emulsion–gel process
Journal of Sol-Gel Science and Technology, 2008Co-Authors: S. Smitha, P. Shajesh, P. Mukundan, Krishna Gopakumar WarrierAbstract:Mesoporous Silica microspheres were synthesised through a sol–emulsion–gel process using Span 80 as the surfactant in Silica sol/n-hexane water in oil emulsion system. Surface modification of the microspheres was done with trimethylchlorosilane to obtain Hydrophobic Silica microspheres. Various parameters related to the synthesis of microspheres, including concentration of surfactant and viscosities of sol were studied. The Hydrophobicity (wettability), thermal stability, porosity, and morphological features were also investigated.
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synthesis of biocompatible Hydrophobic Silica gelatin nano hybrid by sol gel process
Colloids and Surfaces B: Biointerfaces, 2007Co-Authors: S. Smitha, P. Shajesh, P. Mukundan, T.d.r. Nair, Krishna Gopakumar WarrierAbstract:Abstract Silica–biopolymer hybrid has been synthesised using colloidal Silica as the precursor for Silica and gelatin as the biopolymer counterpart. The surface modification of the hybrid material has been done with methyltrimethoxysilane leading to the formation of biocompatible Hydrophobic Silica–gelatin hybrid. Here we are reporting Hydrophobic Silica–gelatin hybrid and coating precursor for the first time. The hybrid gel has been evaluated for chemical modification, thermal degradation, Hydrophobicity, particle size, transparency under the UV–visible region and morphology. FTIR spectroscopy has been used to verify the presence of CH 3 groups which introduce Hydrophobicity to the SiO 2 –MTMS–gelatin hybrids. The Hydrophobic property has also been tailored by varying the concentration of methyltrimethoxysilane. Contact angle by Wilhelmy plate method of transparent Hydrophobic Silica–gelatin coatings has been found to be as high as ∼95°. Oxidation of the organic group which induces the Hydrophobic character occurs at 530 °C which indicates that the surface Hydrophobicity is retained up to that temperature. Optical transmittance of SiO 2 –MTMS–gelatin hybrid coatings on glass substrates has been found to be close to 100% which will enable the hybrid for possible optical applications and also for preparation of transparent biocompatible Hydrophobic coatings on biological substrates such as leather.
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Synthesis of biocompatible Hydrophobic Silica-gelatin nano-hybrid by sol-gel process.
Colloids and surfaces. B Biointerfaces, 2006Co-Authors: S. Smitha, P. Shajesh, P. Mukundan, T.d.r. Nair, Krishna Gopakumar WarrierAbstract:Silica-biopolymer hybrid has been synthesised using colloidal Silica as the precursor for Silica and gelatin as the biopolymer counterpart. The surface modification of the hybrid material has been done with methyltrimethoxysilane leading to the formation of biocompatible Hydrophobic Silica-gelatin hybrid. Here we are reporting Hydrophobic Silica-gelatin hybrid and coating precursor for the first time. The hybrid gel has been evaluated for chemical modification, thermal degradation, Hydrophobicity, particle size, transparency under the UV-visible region and morphology. FTIR spectroscopy has been used to verify the presence of CH(3) groups which introduce Hydrophobicity to the SiO2-MTMS-gelatin hybrids. The Hydrophobic property has also been tailored by varying the concentration of methyltrimethoxysilane. Contact angle by Wilhelmy plate method of transparent Hydrophobic Silica-gelatin coatings has been found to be as high as approximately 95 degrees . Oxidation of the organic group which induces the Hydrophobic character occurs at 530 degrees C which indicates that the surface Hydrophobicity is retained up to that temperature. Optical transmittance of SiO2-MTMS-gelatin hybrid coatings on glass substrates has been found to be close to 100% which will enable the hybrid for possible optical applications and also for preparation of transparent biocompatible Hydrophobic coatings on biological substrates such as leather.
Matthias M Koebel - One of the best experts on this subject based on the ideXlab platform.
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surface chemistry of Hydrophobic Silica aerogels
Chemistry of Materials, 2015Co-Authors: Wim J Malfait, Shanyu Zhao, Rene Verel, Subramaniam Iswar, Daniel Rentsch, Resul Fener, Yucheng Zhang, Barbara Milow, Matthias M KoebelAbstract:The properties of Silica aerogels, and the ability to prepare them by ambient pressure drying, hinge on their chemical surface modification. Until now, quantitative analysis of the surface chemistry has not been possible by state-of-the-art analytical methods. Here, we determine the surface chemistry of six archetypal, ambient pressure dried, Hydrophobic Silica aerogels and open-porous foams with quantitative 1H, 13C, and 29Si and 1H–29Si heteronuclear solid-state NMR spectroscopy. The quality of the external calibration, the validation by elemental analysis, and the consistency among the 1H, 13C, and 29Si MAS NMR data enable us to robustly quantify the surface chemistry of these classical Silica materials. Four aerogels were derived from tetraethoxysilane (TEOS), polyethoxydisiloxane (PEDS), or waterglass precursors and hydrophobized with trimethylsilyl (TMS) groups through immersion in hexamethyldisilazane (HMDZ) in heptane, trimethylchlorosilane (TMCS) in heptane, or hexamethyldisiloxane (HMDSO) in eth...
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Synthesis and characterization of transparent Hydrophobic Silica thin films by single step sol–gel process and dip coating
Journal of Alloys and Compounds, 2010Co-Authors: Digambar Y. Nadargi, J.l. Gurav, N. El Hawi, A.v. Rao, Matthias M KoebelAbstract:Abstract The work presented here describes the room temperature synthesis of highly transparent and Hydrophobic Silica coatings using tetramethoxysilane (TMOS) as a precursor and trimethylchlorosilane (TMCS) as a surface modifying agent via a simple dip coating technique. By varying the TMCS/TMOS molar ratio, the Hydrophobic surface properties have been tailored, covering the entire range from wetting to non-wetting. The contact angle of a water droplet for TMCS/TMOS molar ratios between 0.6 and 1.4 was around 120°; below 0.6 these values continuously decreased to reach approximately 12° for a pure TMOS film. The resulting Silica-based coatings have shown an optical transmission over the visible range up to 85% (in reference to 100% transmission defined by a plain glass substrate). The as-prepared Hydrophobic Silica films retained their Hydrophobicity up to a temperature of 230 °C. At higher temperatures, a gradual loss of the Hydrophobic properties was observed. There is a tradeoff between optical transmittance and non-wetting behavior. The best coating performance in terms of both, high optical transmission and water contact angle were obtained for a TMOS:MeOH:TMCS:H 2 O molar ratio of 1:14.8:1.4:3.3, respectively. In addition to contact angle and optical transparency measurements, the films were also characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and thermal stability measurements.
P. Mukundan - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of mesoporous Hydrophobic Silica microspheres through a modified sol–emulsion–gel process
Journal of Sol-Gel Science and Technology, 2008Co-Authors: S. Smitha, P. Shajesh, P. Mukundan, Krishna Gopakumar WarrierAbstract:Mesoporous Silica microspheres were synthesised through a sol–emulsion–gel process using Span 80 as the surfactant in Silica sol/n-hexane water in oil emulsion system. Surface modification of the microspheres was done with trimethylchlorosilane to obtain Hydrophobic Silica microspheres. Various parameters related to the synthesis of microspheres, including concentration of surfactant and viscosities of sol were studied. The Hydrophobicity (wettability), thermal stability, porosity, and morphological features were also investigated.
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synthesis of biocompatible Hydrophobic Silica gelatin nano hybrid by sol gel process
Colloids and Surfaces B: Biointerfaces, 2007Co-Authors: S. Smitha, P. Shajesh, P. Mukundan, T.d.r. Nair, Krishna Gopakumar WarrierAbstract:Abstract Silica–biopolymer hybrid has been synthesised using colloidal Silica as the precursor for Silica and gelatin as the biopolymer counterpart. The surface modification of the hybrid material has been done with methyltrimethoxysilane leading to the formation of biocompatible Hydrophobic Silica–gelatin hybrid. Here we are reporting Hydrophobic Silica–gelatin hybrid and coating precursor for the first time. The hybrid gel has been evaluated for chemical modification, thermal degradation, Hydrophobicity, particle size, transparency under the UV–visible region and morphology. FTIR spectroscopy has been used to verify the presence of CH 3 groups which introduce Hydrophobicity to the SiO 2 –MTMS–gelatin hybrids. The Hydrophobic property has also been tailored by varying the concentration of methyltrimethoxysilane. Contact angle by Wilhelmy plate method of transparent Hydrophobic Silica–gelatin coatings has been found to be as high as ∼95°. Oxidation of the organic group which induces the Hydrophobic character occurs at 530 °C which indicates that the surface Hydrophobicity is retained up to that temperature. Optical transmittance of SiO 2 –MTMS–gelatin hybrid coatings on glass substrates has been found to be close to 100% which will enable the hybrid for possible optical applications and also for preparation of transparent biocompatible Hydrophobic coatings on biological substrates such as leather.
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Synthesis of biocompatible Hydrophobic Silica-gelatin nano-hybrid by sol-gel process.
Colloids and surfaces. B Biointerfaces, 2006Co-Authors: S. Smitha, P. Shajesh, P. Mukundan, T.d.r. Nair, Krishna Gopakumar WarrierAbstract:Silica-biopolymer hybrid has been synthesised using colloidal Silica as the precursor for Silica and gelatin as the biopolymer counterpart. The surface modification of the hybrid material has been done with methyltrimethoxysilane leading to the formation of biocompatible Hydrophobic Silica-gelatin hybrid. Here we are reporting Hydrophobic Silica-gelatin hybrid and coating precursor for the first time. The hybrid gel has been evaluated for chemical modification, thermal degradation, Hydrophobicity, particle size, transparency under the UV-visible region and morphology. FTIR spectroscopy has been used to verify the presence of CH(3) groups which introduce Hydrophobicity to the SiO2-MTMS-gelatin hybrids. The Hydrophobic property has also been tailored by varying the concentration of methyltrimethoxysilane. Contact angle by Wilhelmy plate method of transparent Hydrophobic Silica-gelatin coatings has been found to be as high as approximately 95 degrees . Oxidation of the organic group which induces the Hydrophobic character occurs at 530 degrees C which indicates that the surface Hydrophobicity is retained up to that temperature. Optical transmittance of SiO2-MTMS-gelatin hybrid coatings on glass substrates has been found to be close to 100% which will enable the hybrid for possible optical applications and also for preparation of transparent biocompatible Hydrophobic coatings on biological substrates such as leather.
P. Shajesh - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of mesoporous Hydrophobic Silica microspheres through a modified sol–emulsion–gel process
Journal of Sol-Gel Science and Technology, 2008Co-Authors: S. Smitha, P. Shajesh, P. Mukundan, Krishna Gopakumar WarrierAbstract:Mesoporous Silica microspheres were synthesised through a sol–emulsion–gel process using Span 80 as the surfactant in Silica sol/n-hexane water in oil emulsion system. Surface modification of the microspheres was done with trimethylchlorosilane to obtain Hydrophobic Silica microspheres. Various parameters related to the synthesis of microspheres, including concentration of surfactant and viscosities of sol were studied. The Hydrophobicity (wettability), thermal stability, porosity, and morphological features were also investigated.
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synthesis of biocompatible Hydrophobic Silica gelatin nano hybrid by sol gel process
Colloids and Surfaces B: Biointerfaces, 2007Co-Authors: S. Smitha, P. Shajesh, P. Mukundan, T.d.r. Nair, Krishna Gopakumar WarrierAbstract:Abstract Silica–biopolymer hybrid has been synthesised using colloidal Silica as the precursor for Silica and gelatin as the biopolymer counterpart. The surface modification of the hybrid material has been done with methyltrimethoxysilane leading to the formation of biocompatible Hydrophobic Silica–gelatin hybrid. Here we are reporting Hydrophobic Silica–gelatin hybrid and coating precursor for the first time. The hybrid gel has been evaluated for chemical modification, thermal degradation, Hydrophobicity, particle size, transparency under the UV–visible region and morphology. FTIR spectroscopy has been used to verify the presence of CH 3 groups which introduce Hydrophobicity to the SiO 2 –MTMS–gelatin hybrids. The Hydrophobic property has also been tailored by varying the concentration of methyltrimethoxysilane. Contact angle by Wilhelmy plate method of transparent Hydrophobic Silica–gelatin coatings has been found to be as high as ∼95°. Oxidation of the organic group which induces the Hydrophobic character occurs at 530 °C which indicates that the surface Hydrophobicity is retained up to that temperature. Optical transmittance of SiO 2 –MTMS–gelatin hybrid coatings on glass substrates has been found to be close to 100% which will enable the hybrid for possible optical applications and also for preparation of transparent biocompatible Hydrophobic coatings on biological substrates such as leather.
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Synthesis of biocompatible Hydrophobic Silica-gelatin nano-hybrid by sol-gel process.
Colloids and surfaces. B Biointerfaces, 2006Co-Authors: S. Smitha, P. Shajesh, P. Mukundan, T.d.r. Nair, Krishna Gopakumar WarrierAbstract:Silica-biopolymer hybrid has been synthesised using colloidal Silica as the precursor for Silica and gelatin as the biopolymer counterpart. The surface modification of the hybrid material has been done with methyltrimethoxysilane leading to the formation of biocompatible Hydrophobic Silica-gelatin hybrid. Here we are reporting Hydrophobic Silica-gelatin hybrid and coating precursor for the first time. The hybrid gel has been evaluated for chemical modification, thermal degradation, Hydrophobicity, particle size, transparency under the UV-visible region and morphology. FTIR spectroscopy has been used to verify the presence of CH(3) groups which introduce Hydrophobicity to the SiO2-MTMS-gelatin hybrids. The Hydrophobic property has also been tailored by varying the concentration of methyltrimethoxysilane. Contact angle by Wilhelmy plate method of transparent Hydrophobic Silica-gelatin coatings has been found to be as high as approximately 95 degrees . Oxidation of the organic group which induces the Hydrophobic character occurs at 530 degrees C which indicates that the surface Hydrophobicity is retained up to that temperature. Optical transmittance of SiO2-MTMS-gelatin hybrid coatings on glass substrates has been found to be close to 100% which will enable the hybrid for possible optical applications and also for preparation of transparent biocompatible Hydrophobic coatings on biological substrates such as leather.
