Facile synthesis of highly flexible polymethylsilsesquioxane aerogel monoliths with low density, low thermal conductivity and superhydrophobicity

In the present work, a facile method was proposed to synthesize highly flexible polymethylsilsesquioxane aerogel (PMSA) monoliths by adopting methyltrimethoxysilane (MTMS) and dimethyldimethoxysilane (DMDMS) as co precursors and ammonia as a base catalyst. The sol-gel process can be completed within 15 min, and gels were directly dried by ambient pressure drying to obtain monolithic PMSAs. The PMSA had low density (as low as 0.087 g cm(-3)), high porosity (90.6-94.5%), macro-pore structure and low thermal conductivity (0.0321-0.0384 W m(-1) K-1). Moreover, excellent compressibility and bending flexibility, together with superhydrophobicity (a contact angle was 162 degrees) were achieved. This work provides an attractive strategy to synthesize highly flexible monolithic PMSAs as promising materials for thermal insulation applications.