surfaktantit

Surfaktantit, known in English as surfactants, are compounds that reduce surface and interfacial tensions between two phases, such as oil and water. They are amphiphilic molecules, containing a hydrophobic tail and a hydrophilic head, which drives their adsorption at interfaces and at the surface of liquids. By accumulating at interfaces, they facilitate wetting, spreading, emulsification, foaming, and dispersion of immiscible substances.

Classification and examples: Surfactants are commonly categorized by the charge of their hydrophilic head: anionic (for example sodium lauryl sulfate), cationic (benzalkonium salts), nonionic (alkylphenol ethoxylates), and zwitterionic or amphoteric (betaines). They can also be grouped by tail structure or source, including synthetic compounds, natural lipids, or biosurfactants such as rhamnolipids, sophorolipids, and lecithin.

Mechanism and properties: Above a characteristic concentration, the critical micelle concentration (CMC), molecules form micelles in solution. This enables solubilization of hydrophobic compounds and changes in interfacial tension. Surfactants also lower the contact angle on surfaces, improving wetting, and stabilize emulsions and foams, depending on molecular structure and concentration.

Applications and environmental aspects: Surfactants are widely used in detergents, personal care products, paints, food processing, pharmaceuticals, oil recovery, and mineral processing. Environmental and health considerations include biodegradability, aquatic toxicity, and regulatory controls. Selection in a formulation balances cleaning performance, stability, and environmental impact.