Preparation of low density organosilica monoliths containing hollow silica nanospheres as thermal insulation materials

In this study, we demonstrated that low density organosilica monoliths (LDM) containing hollow silica nanospheres (HSNS) may have a great potential for the use as thermal insulation materials. First, hydrophilic and hydrophobic HSNS have been prepared by a simple sol-gel method and have an average diameter centered around 120 nm and a shell thickness between 10 and 15 nm. LDM containing HSNS have then been prepared as solid cylindric materials without cracks and with a low bulk density of about 0.17 g/cm3. LDM containing hydrophobic HSNS have shown a measured thermal conductivity of about 0.031 W/(mK), compared to 0.045 W/(mK) of the corresponding LDM without HSNS.