Silica aerogels for potential sensor material prepared by azeotropic mixture

Ambient drying sol-gel processing was used for monolithic silica ambigels in the temperature range of $130-250^{\circ}C$. A new method of mesopore ambigels, which mean the aerogels prepared by ambient pressure drying process synthesis, is suggested at first. This method includes two important approaches. The first point is that $SiO_{2}$ surface modification of wet gel was performed by trimethylchlorosilane in n-butanol solution. This procedure is provided the silica gel mesopore structure formation. The second point is a creation of the ternary azeotropic mixture water/n-butanol/octane as porous liquid, which is effectively provided removing of water such a low temperature by 2 step drying condition under ambient pressure. The silica aerogels, which were prepared by ambient pressure drying from azeotropic mixture of water/n-butanol/octane, are transparent, crack-free and mesoporous (pore size ${\sim}$ 5.6 nm) with surface area of ${\sim}$ $923{\;}m^2/g$, bulk density of $0.4{\;}g/cm^3$ and porosity of 85 %.

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