Surfaktantin

Surfaktantin, or surfactant, is a substance that reduces surface tension at interfaces between liquids, gases, or both. By accumulating at the air–liquid interface, the molecule’s hydrophobic tail and hydrophilic head lower interfacial energy, enabling spreading, wetting, emulsification, and stabilization of foams. Surfactants can be classified by origin (synthetic chemical, biosurfactant, natural) or by charge (anionic, cationic, nonionic, zwitterionic). Biosurfactants are produced by microorganisms such as Pseudomonas and Bacillus and include rhamnolipids and lipopeptides; synthetic surfactants include alkyl sulfates and alkylphenol ethoxylates.

Pulmonary surfactant is a specialized biological surfactant lining the alveoli of the lungs. It consists mainly of phospholipids, especially dipalmitoylphosphatidylcholine, with surfactant proteins SP-A, SP-B, SP-C, and SP-D. It reduces alveolar surface tension during breathing, preventing collapse and stabilizing lung function. Premature infants lacking adequate surfactant may develop respiratory distress syndrome; treatment includes administration of exogenous surfactant.

Beyond physiology, surfactants are widely used in detergents and cleaning products, emulsification in foods and cosmetics, and pharmaceutical formulations. They also aid in enhanced oil recovery and soil remediation. The environmental impact varies by compound; many synthetic surfactants can be toxic to aquatic organisms, whereas some biosurfactants are biodegradable and considered more environmentally friendly.

Manufacture involves petrochemical processing or fermentation for biosurfactants. Key properties include the critical micelle concentration, hydrophilic–lipophilic balance, and foaming tendency.