New Transparent Methylsilsesquioxane Aerogels and Xerogels with Improved Mechanical Properties

摘要

Transparent hydrophobic MSQ aerogels and aerogel-like xerogels have been obtained from a single trifunctional precursor, MTMS. Two kinds of surfactants were used to suppress phase separation between the hydrophobic MTMS-derived species and polar solvents. Urea acts as a polymerization accelerator to freeze the structure prior to macroscopic phase separation. This modified acid-base system allowed a single-step sol-gel preparation to be used to fabricate a material with good structural homogeneity and transparency. Some of the obtained gels showed reversible deformation during uniaxial compression tests and thus were successfully dried by evaporation drying under ambient pressures, during which time compressive stress was also exerted on the gel. The obtained xerogels exhibited similar pore properties to corresponding aerogels (i.e., they maintained high porosity and transparency). Together with the easy handling resulting from the unique mechanical properties, our new method may lead to lower-cost and larger-scale industrial processes, suggesting that aerogels will find increased usage in general applications such as insulators for windows and solar heat panels.