Xerogels
Xerogel is a solid obtained by drying a gel so that the liquid phase is removed by evaporation, leaving behind a rigid, porous network. In gel formation, a sol-gel process creates a three-dimensional network of inorganic or organic material within a liquid. When the liquid is removed by evaporation at ambient or moderate pressure, capillary forces cause shrinkage and result in a xerogel, in contrast to an aerogel produced by supercritical drying that minimizes capillary damage.
Xerogels commonly use silica, but metal oxides such as alumina and titania and organic polymers can also
Applications include catalyst supports, adsorbents, chromatography supports, insulating materials, sensors, optical hosts, and energy storage components.
Compared with aerogels, xerogels generally have higher bulk density and lower porosity, and their drying-induced shrinkage