aerogelu

Aerogel is a synthetic porous ultralight solid derived from a gel, in which the liquid component of the gel has been removed and replaced with gas. This process yields a material with extremely low density, high porosity, and notable insulating and optical properties. The most common form is silica aerogel, but aerogels based on carbon, alumina, metal oxides, or polymers are also produced.

Production typically follows a sol-gel process: a wet gel is formed from a precursor, solvents are exchanged, and the liquid is removed without collapsing the gel network. Drying is often achieved by supercritical drying with carbon dioxide or by surface modification to enable ambient-pressure drying. Silica aerogels can be manufactured as monoliths, granules, or composites and may be doped or reinforced to improve mechanical strength.

Key properties include densities as low as a few thousandths of a gram per cubic centimeter, porosity up to about 99.8%, and very low thermal conductivity (around 0.013–0.020 W/mK for suitable forms). They are often translucent or transparent and can be engineered for varying optical, thermal, and mechanical performance. However, many aerogels are brittle and require reinforcement for structural applications.

Applications span thermal insulation for buildings and refrigeration, cryogenics, spacecraft insulation and protective systems, daylighting panels and skylights, and lightweight insulating materials in clothing or equipment. The development of aerogels began in the 1930s with the work of Samuel Stephens Kistler, and commercialized in the late 20th century, with notable use in space missions such as the Stardust project for particle capture.

Safety and environmental notes include the inertness of bulk aerogel materials, tempered by the hazards of silica dust during processing. Appropriate handling, containment, and personal protective equipment are advised.