Super Thermal Insulating SiO₂ Cryogels Prepared by Vacuum Freeze Drying

Abstract:

Traditionally, silica aerogels with low thermal conductivity are prepared by supercritical drying, however, the process is expensive and hazardous due to it run in autoclaves. In order to overcome these disadvantages, a cheaper and safer process, drying at ambient pressure has been developed for decades, but tedious repetitive gel washing and solvent exchange steps are involved. Therefore, in the present study, a novel vacuum freeze-drying was utilized to prepare the super thermal insulating SiO2 cryogels. The wet gels were synthesized via acid-base catalysis using tetraethoxysilane (TEOS) as a silica precursor and ethanol as a solvent. After vacuum freeze drying, nanoporous SiO2 cryogels with low density in the range of 0.08-0.15 g/cm3 were obtained.

• Periodical: Advanced Materials Research (Volumes 105-106)
• Pages: 851-854
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.105-106.851
• Online since: April 2010
• Authors: Li Fen Su, Lei Miao, Gang Xu, Sakae Tanemura
• Keywords: SiO₂ Cryogel, Super Thermal Insulating, Vacuum Freeze-Drying

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