silicone

Silicone is a family of synthetic polymers built around a silicon-oxygen backbone (siloxane) with organic groups attached to silicon. The term covers liquids, gels, rubbers, and resins. Silicones are distinct from silica (SiO2) and from simple silicon-containing chemistries.

The most common silicone polymer is polydimethylsiloxane (PDMS), where each silicon is linked to two oxygen atoms and two methyl groups. Variants include silicone oils, elastomeric rubbers, and resins. Materials may be crosslinked to form solids or remain as fluids; functional groups enable curing and adhesion.

Key properties include high thermal stability, chemical resistance, electrical insulation, low surface energy, and flexibility over a broad temperature range. They are relatively inert and biocompatible in many forms, though additives and fillers influence performance and safety. Silicones resist weathering and water, making them versatile for long-lasting applications.

Manufacture involves organosilicon chemistry derived from silica feedstocks. Common routes include hydrolysis and polycondensation of chlorosilanes to produce siloxane polymers, such as PDMS. Processing methods include extrusion, molding, and various curings to yield oils, gels, or elastomers.

Applications span sealants, adhesives, lubricants, electrical insulators, cookware, medical devices, cosmetics, and automotive and construction components. They are prized for durability and temperature tolerance, but environmental and health considerations on additives and persistence exist and guide responsible use and disposal.