Surfactants lower the surface tension between two liquids and act as detergents, wetting agents, emulsifiers, foaming agents, and dispersants. They have good cleansing and foaming properties. Surfactants are classified as either primary or secondary surfactants and have different chemical structures (anionic, non-ionic, amphoteric and quarternary). Besides cleaning, other functions of surfactants can include, wetting, conditioning, emulsifying and thickening.