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°) were achieved. This work provides an attractive strategy to synthesize highly flexible monolithic PMSAs as promising materials for thermal insulation applications.