<Research Report>Sol-Gel Synthesis and Characterization of Transparent Porous Materials

Synthesis and characterization of novel organic-inorganic hybrid aerogels are reviewed. These aerogels are prepared by using a 2-step acid/base sol-gel reaction and composed of polymethylsilsesquioxane (PMSQ, CH[3]SiO[1.5]). Pore structures in the 10–100 nm scale have been characterized by the small angle X-ray scattering (SAXS) and gas adsorption techniques. Mechanical properties have also been investigated by the uniaxial compression. It has been revealed that these aerogels show an outstanding elastic behavior like a sponge; aerogels are compressed without collapsing up to 80% followed by almost perfect recovery called "spring-back". The improved mechanical properties allow a simplified process of preparation and easier handling compared to the conventional silica aerogels which are remarkably brittle