aerogel

Aerogel is an artificial material formed by replacing the liquid in a gel with gas, leaving a very lightweight dendritic structure. Its fine pore structure limits heat transfer and makes it an effective thermal insulator.

Types of aerogel include silica, carbon, and alumina. Traditional aerogels can be brittle and easily damaged, so they usually need protection or reinforcement.

The pores and the remaining solid framework account for the material's low density and insulating behavior. Aerogel insulation need not contain an evacuated space like a vacuum-insulated panel.