What is the physical structure of aerogels?
Aerogels feature an extremely high density of interconnected pores. These pores are extremely small with diameters of less than 100 nanometers, and there is considerable variation in pore size below this level. This porous nature results in a very large total surface area (i.e., including the surfaces in each pore), and the interconnected structure of these open pores provides access to this entire surface area for gasses and liquids for use in chemical reactions and for making composites. There is an inverse relationship between the surface area and density. These and other properties can be controlled during production according to the intended application. Silica aerogels contain primary particles of 2nm to 5nm in diameter. This very small size provides an extremely great surface-to-volume ratio and a corresponding high specific surface area. Consequently, the chemistry of the interior surface of aerogels plays a dominant role in its chemical and physical behavior. It is this proper
