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http://dx.doi.org/10.5369/JSST.2006.15.5.371

Influence of solvent on the nano porous silica aerogels prepared by ambient drying process  

Ryu, Sung-Wuk (Thin Film Materials Research Center, Korea Institute of Science and Technology)
Kim, Sang-Sig (Department of Electrical Engineering, Korea University)
Oh, Young-Jei (Thin Film Materials Research Center, Korea Institute of Science and Technology)
Publication Information
Journal of Sensor Science and Technology / v.15, no.5, 2006 , pp. 371-377 More about this Journal
Abstract
Nano porous, transparent silica aerogels monoliths were prepared under ambient drying (1 atm, $270^{\circ}C$) condition by the combination of sol-gel process and surface modification with subsequent heat treatment. Three kinds of solvent, n-hexane, n-heptane and xylene, were selected in the point view of low surface tension and vapor pressure in order to restrain a formation of cracks during drying. Crack-free silica aerogels with over 93 % of porosity and below $0.14g/cm^3$ of density were obtained by solvent exchange and surface modification under atmosphere condition. Optimum solvent was confirmed n-heptane among these solvents through estimation of FT-IR, TGA, BET and SEM. Modified silica aerogel exhibited a higher porosity and pore size compare to unmodified aerogels. Hydrophobicity was also controled by C-H and H-OH bonding state in the gel structure and heat treatment over $400^{\circ}C$ effects to the hydrophobicity due to oxidation of C-H radicals.
Keywords
aerogel; surface modification; ambient drying; solvent; surface tension;
Citations & Related Records
Times Cited By KSCI : 1  (Citation Analysis)
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