Surface Active Agents

Surfactants or surface-active agents are amphiphiles as their molecular structure consists of a polar hydrophilic 'head' and a non-polar hydrophobic 'tail'.

Due to their ability to adsorb at interfaces, surfactants lower the interfacial tension between two phases, enabling their use as emulsifiers, detergents, dispersing agents, and more.

Surfactants form micelles when they exceed their critical micelle concentration, a phenomenon crucial to their physicochemical properties.

The shape of these micelles can be predicted using the surfactant parameter, which considers the volume of the hydrophobic tail, the area of the hydrophilic head, and the tail's maximum length.

Surfactants are categorized based on the charge of their hydrophilic head. Anionic surfactants include compounds like carboxylate, cationic ones include ammonium, non-ionic surfactants contain polyoxyethylene alcohol, and amphoteric surfactants include triglycine.

The Hydrophile-Lipophile Balance measures the balance between hydrophilic and hydrophobic parts of a surfactant molecule. HLB values range from 1 to 40, with low values showing oil solubility and high values showing water solubility.