Journal of Sensor Science and Technology (센서학회지)

The Korean Sensors Society (한국센서학회)
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Influence of solvent on the nano porous silica aerogels prepared by ambient drying process

상압건조 나노다공성 실리카 에어로젤에 대한 용매의 영향

  • 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)
  • 류성욱 (한국과학기술연구원 박막재료연구센터) ;
  • 김상식 (고려대학교 전기공학과) ;
  • 오영제 (한국과학기술연구원 박막재료연구센터)
  • Published : 2006.09.30
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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.

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References

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