Tensiide

Tensiide are surface-active agents, compounds that reduce surface tension between two immiscible phases, most commonly water and oil or water and air. They are amphiphilic, with a hydrophobic tail and a hydrophilic head, which drives their accumulation at interfaces and, above a concentration known as the critical micelle concentration, the formation of micelles.

They are classified by the charge of the hydrophilic head: anionic, cationic, nonionic, and zwitterionic tensides. Their properties—lowering surface tension, improving wetting, enabling emulsification, stabilizing dispersions, and controlling foaming—depend on molecular structure and concentration.

Common uses include detergents and cleaners, personal care products, paints and coatings, agrochemicals as adjuvants, and pharmaceutical formulations.

Mechanistically, tensides orient at interfaces and, when concentrated, self-assemble into micelles that solubilize hydrophobic substances. Important concepts include the critical micelle concentration and the hydrophobic–lipophilic balance, which influence performance and biodegradability.

Environmental and safety considerations vary by type. Many tensides are readily biodegradable and have moderate aquatic toxicity, but certain cationic tensides can be more hazardous to aquatic life, and some surfactants irritate skin or eyes. Regulations such as REACH govern use, labeling, and safe handling.

Examples include sodium lauryl sulfate (SLS), sodium dodecylbenzenesulfonate (SDBS), alkyl polyglucosides (nonionic), and cetyltrimethylammonium bromide (CTAB).