Xerogele

Xerogele is a term used in materials science to denote a class of dried gel networks, often treated as a variant spelling of xerogel. The name derives from xero-, meaning dry, and gel, reflecting the process by which a wet gel is transformed into a solid with a porous internal structure. In practice, xerogele describes porous solids formed when solvent is removed from a gel, leaving a rigid skeleton with sizeable surface area.

Xerogele materials are characterized by high porosity, low density, and a tunable pore structure that ranges from nanometers to micrometers. The drying step is critical: removing solvent by evaporation can induce capillary forces that collapse pores, whereas carefully controlled methods preserve porosity. Common drying techniques include ambient evaporation, freeze-drying, and supercritical drying, with the latter often used to minimize pore collapse.

A wide range of chemical compositions yields xerogele networks. Silica-based xerogeles are among the most studied, but metal oxides (such as alumina and titania), carbon xerogels, and organic–inorganic hybrids are also reported. Synthesis typically involves sol–gel chemistry to form a wet gel, followed by a drying step that preserves the porous framework.

Applications of xerogele span insulation, catalysis, adsorption and separation, sensor supports, and drug delivery matrices. Their advantages include high surface area, chemical tunability, and mechanical stability relative to some other porous materials. Common challenges involve drying-induced shrinkage and cracking, controlling pore size distribution, and achieving reproducible mechanical properties.

In summary, xerogele are versatile porous solids produced by drying gels, with properties and uses closely tied to the chemistry of the gel network and the chosen drying method. Related terms include xerogel, aerogel, and hydrogel.