Shlyakhtina, An. Oh, Young-Jei 2024-01-20T23:33:32Z 2024-01-20T23:33:32Z 2021-09-03 2008-03-15 0022-3093 https://pubs.kist.re.kr/handle/201004/133648 Transparent SiO2 aerogels were prepared by two-step sol-gel processing followed by ambient pressure drying at temperatures from 70 to 250 degrees C. The wet gels were synthesized via acid-base catalysis using tetraethyl orthosilicate as a silica precursor and isopropanol as a solvent. Isopropanol was exchanged with n-butanol, and the gel surface was modified using a trimethylchlorosilane solution in n-butanol. Next, the solvent was exchanged in several steps with saturated hydrocarbon in order to obtain pore fluids containing azeotropic mixtures of water, n-butanol and a corresponding hydrocarbon (hexane, heptane, octane, nonane). Ambient pressure drying was performed in two steps, at the boiling points of the ternary azeotropes and hydrocarbons, respectively. In this way, transparent, crack-free aerogels of different shapes, with a specific surface area of 1000 m(2)/g, average pore diameter of similar to 40-55 angstrom and density in the range 0.4-0.57 g/cm(3) were obtained. (c) 2007 Published by Elsevier B.V. English ELSEVIER SCIENCE BV SILICA AEROGELS OXIDE AEROGELS GEL Transparent SiO2 aerogels prepared by ambient pressure drying with ternary azeotropes as components of pore fluid Article 10.1016/j.jnoncrysol.2007.10.033 1 JOURNAL OF NON-CRYSTALLINE SOLIDS, v.354, no.15-16, pp.1633 - 1642 JOURNAL OF NON-CRYSTALLINE SOLIDS 354 15-16 1633 1642 scie scopus 000254353300008 2-s2.0-39149103731 Materials Science, Ceramics Materials Science, Multidisciplinary Materials Science Article SILICA AEROGELS OXIDE AEROGELS GEL aerogel azeotrope nanoparticles porosity silica