Aerogel generally refers to a lightweight nano-solid material with nanometer-sized ultrafine particles aggregated to form a nanoporous network structure, and the pores of the network are filled with a gaseous dispersion medium. Aerogels are a solid, but 99% are made of gas, and they look like clouds. Aerogels are sometimes called "solid smoke" or "frozen smoke" because of their translucent color and ultra-light weight.
The most common aerogel is silica aerogel. SiO2 aerogel is a lightweight nano-porous amorphous solid material with excellent thermal and thermal insulation properties. Its porosity is as high as 80-99.8%. The typical size of pores is 1-100 nm and the specific surface area is 200-1000 m2. / g, while the density can be as low as 3 kg / m3, and the thermal conductivity at room temperature can be as low as 0.012 W / (m • k). It is precisely because of these characteristics that aerogel materials have a wide range of application potentials in thermal, acoustic, optical, microelectronic, and particle detection.