A sol-gel route to very high porosity silica aerogels

This report discusses the preparation and characterization of very high porosity silica aerogels. The data presented here suggests a microstructure for the very high porosity silica aerogel that differs from the bead-like structure proposed for single-step, base catalysed TMOS aerogels. The data is consistent with an interlinked polymer chain-like structure, with an average chain diameter of 2-3nm and an average chain length >15nm. The increased transparency of these new aerogels also indicates that they have very small particles and uniform pores less than 50nm.