• Proceedings of the Korean Fiber Society Conference
• /
• 2001.04a
• /
• pp.95.1-98
• /
• 2001

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.13 no.2
• /
• pp.73-78
• /
• 2003

The influence of calcination temperature on the pore structure of freeze dried silica gel derived from tetraethyl orthosilicate (TEOS) was investigated using $N_2$adsorption and mercury intrusion techniques. Freeze dried material contained not only 4-6 nm sized mesopores and 6-10 $\mu\textrm{m}$ sized macropores, but minor micropores. The change of pore structure due to the increase of calcination temperature was dependant upon the degree of densification.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.27 no.2
• /
• pp.298-302
• /
• 2013

In this study, the effect of sericin on synthesis of the silica was investigated. Using the mixture of sericin solution and tetraethyl orthosilicate (TEOS), it was confirmed that silica could be synthesized in the presence of sericin, which was verified by thermal gravimetric analysis (TGA), Fourier-transformed infrared spectrometer (FT-IR) and nuclear magnetic resonance spectrometer (NMR) analysis. The TGA and FT-IR data revealed that silica-sericin complex was formed as a final product. Based on the TGA result, the content of silica and sericin in the complex would be 87 and 13%, respectively. The degree of silica condensation was higher than the natural biosilica. It could be concluded that sericin can induce the synthesis of silica directly from TEOS, which is similar to silicatein from marine sponges.

• Applied Chemistry for Engineering
• /
• v.30 no.1
• /
• pp.68-73
• /
• 2019

We prepared hydrophobic silica particles by a sol-gel process from tetraethyl orthosilicate (TEOS), followed by coupling the reaction with octyltrimethoxysilane (OTMS) or hexadecyltrimethoxysilane (HDTMS) under various reaction conditions. We confirmed the extent of silica surface modification with organic compounds by SEM-EDS, thermogravimetry and elemental analysis. The silica particles obtained after the hydrolysis reaction of TEOS in ethanol at $50^{\circ}C$ for 24 h and the coupling reaction with OTMS for 2 h at the same temperature displayed the optimum performance in terms of the dispersity in an organic solvent and the surface roughness of films composited with epoxy resins. The oxygen permeability of the composite film with modified-silica was 12% lower than that of using the film without modified-silica.

• Membrane Journal
• /
• v.20 no.4
• /
• pp.278-289
• /
• 2010

A series of composite membranes based on sulfonated poly(arylene ether sulfone) (SPAES) were prepared via addition of tetraethyl orthosilicate (TEOS) and solution casting method. The morphological structure, water uptake, proton conductivity of the resulting composite membranes were extensively investigated as function of the content of TEOS. By the sol-gel reaction, TEOS molecules were not completely converted to $SiO_2$ particles, but formed only oligomer-type. Also, EDS confirms that the resulting silicon dioxide was homogeneously distributed in the composite membranes. As the content of TEOS increased, the prepared membranes increased water uptake and proton conductivity at high temperature and low relative humidity condition. In particular, considerably high proton conductivity (0.015 S/cm) at $120^{\circ}C$ and 48%RH was demonstrated in the composite membrane containing 200% TEOS, which is 10 times greater than that of unmodified SPAES membrane. Also, the composite membranes were found to have enhanced thermal stability compared to the unmodified membrane.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.3
• /
• pp.1067-1070
• /
• 2012

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.7 no.3
• /
• pp.465-470
• /
• 2006

Coating are needed on ophthalmic lenses to enhance both the mechanical durability of the relatively soft plastic surface and the optical performance of lenses. Organic-inorganic hybrid materials as molar ratio of 3-glycidoxypropyltrimethoxysilane(GPTS), methyltrimethoxysilane(MTMS) and tetraethyl orthosilicate(TEOS) were used to improve the surface characteristics and the optical properties on allyl diglycol carbonate lenses. Coating for these plastics were at $140^{\circ}C$ for 4hrs, applied using the sol-grl process flow-coating technique. The coated lens properties of transmittance, adhesion, pencil hardness, abrasion resistance, hot water resistance and chemical resistance were investigated. The optimum properties was obtained when the ratio of GPTS : MTMS : TEOS was 1:1:2, respectively.

• Journal of Korean Ophthalmic Optics Society
• /
• v.3 no.1
• /
• pp.237-242
• /
• 1998

A transparent and colorless $80SiO_2-20TiO_2$(mol%) thin films on soda-lime-silica slide glass and sapphire substrate were obtained by spin-coating technique using tetraethyl orthosilicate and titanium trichloride as starting materials. The prepared film annealed at $750^{\circ}C$ showed a high transmittance and a low reflectance. For the $SiO_2-TiO_2$ films on slide glasses, a strong interaction between the sodium ion and oxygens is properbly the origin of the good stability to the high temperature and the high humidity.

• Journal of the Korean Electrochemical Society
• /
• v.16 no.3
• /
• pp.184-189
• /
• 2013

$Ba_2SiO_4:Eu^{2+}$ ($B_2S:Eu^{2+}$) powders were prepared by firing the dry gel obtained by the sol-gel and the hybrid process (sol-gel and combustion), respectively, and their structure and luminescence were investigated. Tetraethyl orthosilicate (TEOS) was used as a Si source. The phase transition was observed with the TEOS content. With 1.2M TEOS, the powders prepared by the sol-gel process without prior calcination were composed of the $B_2S:Eu^{2+}$ single phase, whereas those by the sol-gel and the hybrid process with prior calcination consisted of the dominant $B_2S:Eu^{2+}$ and minor $BaSiO_3:Eu^{2+}$ ($BS:Eu^{2+}$) phases and their emission intensities were approximately two times higher than those without prior calcination. The hybrid process could reduce the process time innovatively compared to the sol-gel process, even though the former was a little inferior to the latter in the emission intensity of $B_2S:Eu^{2+}$. With 1.1M TEOS, the $B_2S:Eu^{2+}$ single phase was obtained by the hybrid process, and its green emission was observed at 505 nm originated from the $4f^65d^1{\rightarrow}4f^7$ transition of $Eu^{2+}$ ions.

• 한국문화재보존과학회:학술대회논문집
• /
• 2007.05a
• /
• pp.67-68
• /
• 2007

Tetraethyl orthosilicate (TEOS)로 형성된 gel의 film 형성 특성을 증가시키기 위하여 (3-glycidyloxypropyl)trimethoxysilane (GPTMS)와 1,2-bis(triethoxysilyl)ethane (BTEOS)를 추가한 유기-무기 복합 용액을 제조하였다. 화강암과 사암에 적용한 후, 접촉 각 및 고형화 시간, silicate의 함유량, 수분 흡수율 및 석재에 적용되었을 때의 공극률 변화를 측정하여 silicate를 기본으로 하는 복합제의 특성을 분석하였다.