A porous polymer–silica composite with a “vespula-like” structure for thermal insulating materials prepared via high pressure phase control

A new fabrication route for polymer–silica composite foams is developed which includes (1) a homogeneous mixture of polymer, silicon alkoxide, and CO2 under high pressure and (2) multiple phase separations of the mixture induced by a pressure drop. The method provides a unique “vespula like” porous polymer composite in which the cells include spherical silica-rich microparticles. This is an important milestone for “isolated silica aerogel in a polymer foam” for high performance and flexible thermal insulators.