Formation and Characterization of OH Free Silica Aerogel through Surface Treatment

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J. Korean Ceram. Soc. > Volume 33(12); 1996 > Article

Journal of the Korean Ceramic Society 1996;33(12): 1339.

표면처리에 의한 수산기 없는 실리카 에어로겔의 형성 및 특성연구

홍정균, 조문호, 김동준¹, 박형호¹, 현상훈

연세대학교 세라믹공학과
¹연세대학교 세라믹공학

Formation and Characterization of OH Free Silica Aerogel through Surface Treatment

ABSTRACT

Silica aerogel with ultra high porosity(>90%) and large surface area(~1000 m2/g) is prepared by supercritical drying of wet gel. We observed the change of surface bonding states of aerogel which contains hydroxyl groups (OH). physisorbed water and some alkoxyl groups (OR, R : C2H5 or CH3) before and after the surface treatment using X-ray photoelectron spectroscopy and Fourier transform-infrared spectroscopy. Almost all of hydroxyl groups and alkoxyl groups were removed by thermal treatment at 80$0^{circ}C$ under vacuum but single isolated OH bond (Si-OH) remained. In order to achieve the OH free surface of aerogel thermally treated aerogel was successively retreated with halogen compounds (NH4F and Na2SiF6) and we could achieve the OH free aerogel with Na2SiF6

Key words: Silica aerogel, FT-IR, XPS, Thermal treatment, Chemical treatment