• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.97-98
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• 2009

Here, we describe a versatile strategy for precise control of the optoelectrical properties of the single walled carbon nanotube (SWNT)/silane binder hybrid films by noncovalent hybridization. Stable SWNT/silane binder solutions were prepared by direct mixing of high concentration CNT solutions and silane sol solutions. The critical binder content was determined by varying the amount of binder in the SWNT/binder solutions. A binder content of 50 wt% was used to prepare the other SWNT/binder solutions. This study demonstrates how the intermolecular interactions between the SWNTs and the silanes can affect the conductivity of the CNT/binder network films by characterizing the optoelectrical and Raman spectroscopic properties of the SWNT/silane films containing silane binders with various functional groups. The use of the PTMS binder with phenyl groups was found to be most effective in the fabrication of transparent and conductive films on glass substrates. Such a precise control of the optoelectrical properties of SWNT/binder films can be useful to fabricate the high performance conductive thin films, with ramifications for understanding the fundamental intermolecular interaction in carbon materials science.

• Applied Chemistry for Engineering
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• v.17 no.6
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• pp.580-585
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• 2006

UV-thermal dually curable coating materials were prepared by the sol-gel method. Nano-sized colloidal boehmite was treated with various organo silane coupling agents. These materials could be well dispersed in various alcohols and relatively polar organic solvents such as tetrahydrofuran and acetonitrile. The coating films were prepared by a spin coating method on various substrates, which were characterized by FT-IR, Si/Al CP MAS NMR spectra, UV-Vis spectrophotometer, FE-SEM, Taber abraser, haze meter, and pencil hardness tester. The effects of molar ratio and types of silane coupling agents, curing method and ion-shower treatment were investigated. Dually curable coating method offered an optimally good quality film in both hardness and transmittance. The transparency and the hardness of the prepared films were increased with amounts of 3-(trimethoxysilyl)propylmethacrylate, and (3-glycidyloxypropyl)trimethoxysilane, respectively. The adhesion between coated layer and substrate could be enhanced by ion-shower treatment.

• Korean Journal of Materials Research
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• v.26 no.12
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• pp.733-740
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• 2016

$Al_2O_3$ nanosol dispersed under ethanol or N-Methyl-2-pyrrolidone(NMP) was studied and optimized with various dispersion factors and by utilizing the silane modification method. The two kinds of $Al_2O_3$ powders used were prepared by thermal decomposition method from aluminum ammonium sulfate$(AlNH_4(SO_4)_2)$ while controlling the calcination temperature. $Al_2O_3$ sol was prepared under ethanol solvent by using a batch-type bead mill. The dispersion properties of the $Al_2O_3$ sol have a close relationship to the dispersion factors such as the pH, the amount of acid additive(nitric acid, acetic acid), the milling time, and the size and combination of zirconia beads. Especially, $Al_2O_3$ sol added 4 wt% acetic acid was found to maintain the dispersion stability while its solid concentration increased to 15 wt%, this stability maintenance was the result of the electrostatic and steric repulsion of acetic acid molecules adsorbed on the surface of the $Al_2O_3$ particles. In order to observe the dispersion property of $Al_2O_3$ sol under NMP solvent, $Al_2O_3$ sol dispersed under ethanol solvent was modified and solvent-exchanged with N-Phenyl-(3-aminopropyl)trimethoxy silane(APTMS) through a binary solvent system. Characterization of the $Al_2O_3$ powder and the nanosol was observed by XRD, SEM, ICP, FT-IR, TGA, Particles size analysis, etc.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.105-108
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• 2002

Polyimide-epoxysilane (coupling agent) composites were reacted with oligomeric PDMS, a condensation product of difunctional silane, by a sol-gel process and were then dried into films. And then, the surface, mechanical, and electric properties were measured. The study showed that PDMS existed in the polyimlde matrix by the use of FT-IR. In the mechanical properties, the maximum elongation and toughness was increased in the polyimide with silane-groups. But the maximum tensile strength was slightly decreased. And the intensive dispersion of the silane-groups on the surface of polyimide was ascertained through XPS measurement. In the electric properties, AC break down voltage was increased by increasing the amount of difunctional silane. This experiment showed that PDMS added polyimide had better mechanical and electric properties than classical materials.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.551-552
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• 2007

Coating films were prepared from silane-terminated Colloidal silaca(CS) and UV-curable acrylate resin. The silane-terminated CSs were synthesized from CS and methyltrimethoxysilane(MTMS) and then treated with 3-methacryloxypropyltrimethoxysilane(MAPTMS)/3-glycidoxypropyltrimethoxysilane( GPTMS)/vinyltrimethoxysilane(VTMS) by sol-gel process, respectively. The silane-terminated CS and acrylate resin were hybridized using UV-curing system. Thin films of hybrid material were prepared using spin coater on the glass. Their hardness, contact angle and transmittance improved with the addition of silane-terminated CS.

• Macromolecular Research
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• v.9 no.3
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• pp.171-178
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• 2001

We report the diffraction behavior of the functionalized sol-gel film composed of two different silanes. One silane (SGDR1) contains disperse red 1 (DR1) that is composed of an azobenzene unit. The other silane (SGCHC) bears a chalcone derivative that is photocrosslinkable under UV irradiation. Two-beam coupling method was employed for fabricating the diffraction gratings. The dynamics of formation and erasure of the gratings was studied in term of the variation of the diffraction efficiency. The decaying behavior of the polarization efficiency was also observed after turning off the two pump beams. For complete erasure of the diffraction gratings, we irradiated the linearly polarized single beam. During two-beam coupling, we irradiated UV light on the film surface. The effects of the photocrosslink between the double bonds in chalcone units on the value and dynamic properties of diffraction efficiency are mainly studied in this work.

• Journal of the Korean Ceramic Society
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• v.29 no.8
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• pp.593-600
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• 1992

Through sol-gel processing, Inorganic-organic composite was obtained. The influence of water content used in hydrolysis on the bonding state, microstructure, strength, and elongation into IR, NMR, Tg, etc. As the water content was increased, the bonds between inorganic Si-(OH) and organic Si-(OH) increased, and relatively denser microstructure was formed. Tensile strength and elongation decreased with amount of water content.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.05a
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• pp.215-225
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• 2002

In order to enhance the thermal stability of binder materials of bonded type solid lubricants, several combinations of metal-alkoxide based sol-gel materials such as methyltrimethoxysilane(MTMOS), $titaniumisopropoxide(Ti(Opr^{j})_{4})$, $zirconiumisopropoxide(Zr(Opr^{j})_{4})$ and $aluminumbutoxide(Al(Obu^{t})_{4})$ were chemically modified by epoxy-, acrylic- and fluoro-silane compounds, respectively, in this work. Friction and wear characteristics of these hybrid ceramic materials were tested with a micro tribe-tester where a reciprocating steel ball slid on a test material, and the tribological property was also evaluated with respect to both heat-curing temperature and tile time. Test results generally showed that hybrid ceramic materials modified by epoxy-silane compounds had a low friction compared to others. And the higher heat-curing temperature and the longer heat treatment time resulted in the higher friction and the lower wear. IR spectroscopic analyses revealed that it was caused mainly by the increased metal oxide content in hybrid ceramics when the heat-curing temperature was over $320^{\circ}C$.

• Journal of the Korean Applied Science and Technology
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• v.26 no.3
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• pp.288-296
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• 2009

In this study, the silica-based hybrid material with high barrier property was prepared by incorporating ethylene-vinyl alcohol (EVOH) copolymer, which has been utilized as packaging materials due to its superior gas permeation resistance, during sol-gel process. In preparation of this EVOH/$SiO_2$ hybrid coating materials, the (3-glycidoxy-propyl)-trimethoxysilane (GPTMS) as a silane coupling agent was employed to promote interfacial adhesion between organic and inorganic phases. As confirmed from FT-IR analysis, the physical interaction between two phases was improved due to the increased hydrogen bonding, resulting in homogeneous microstructure with dispersion of nano-sized silica particles. However, depending on the range of content of added silane coupling agent (GPTMS), micro-phase separated microstructure in the hybrid could be observed due to insufficient interfacial attraction or possibility of polymerization reaction of epoxide ring in GPTMS. The oxygen barrier property of the mono-layer coated BOPP (biaxially oriented polypropylene) film was examined for the hybrids containing various GPTMS contents. Consequently, it is revealed that GPTMS should be used in an optimum level of content to produce the high barrier EVOH/$SiO_2$ hybrid material with an improved optical transparency and homogeneous phase morphology.

• Tribology and Lubricants
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• v.18 no.5
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• pp.324-332
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• 2002

In order to enhance the thermal stability of binder materials of bonded type solid lubricants, several metal-alkoxide based sol-gel materials such as methyltrimethoxysilane(MTMOS), titaniumisopropoxide$(Ti(Opr^i)_4),$ zirconiumisopropoxide $(Zr(Opr^i)_4)$ and aluminumbutoxide$(Al(Obu^t)_4)$ were chemically modified by epoxy-, acrylic- and fluoro-silane compounds, respectively. Friction and wear characteristics of these hybrid ceramic materials were tested with a micro tribo-tester, and evaluated with respect to both heat-curing temperature and the time. Test results generally showed that hybrid ceramic materials modified by epoxy-silane compounds had a low friction compared to others. And the higher het-curing temperature and the longer heat treatment time resulted in the higher friction and the lower wear. IR spectroscopic analyses revealed that these results were caused mainly by the increased metal oxide content in hybrid ceramics when the heat-curing temperature was over $320^{\circ}C.$