Some thermal and optical properties of a new transparent silica xerogel material with low density

Abstract In this work we have studied a new type of monolithic silica aerogels (xerogels) made without supercritical drying. The xerogels are produced by performing washing and ageing treatments on the alcogel before drying at ambient pressure. Densities as low as 0.26 g/cm3 have so far been obtained and the thermal conductivity of air-filled xerogels has been measured down to 18 mW / mK. Properties of this new type of silica xerogels have been compared to the properties of silica xerogel made by supercritical drying. Densitym pore size, thermal conductivity and optical transmittance are reported, and some application advantages are discussed.