THE ROLE OF SURFACTANTS IN LIQUID SOAPS AND ITS ANTIMICROBIAL PROPERTIES

A typical liquid soap is composed of a mixture of different types of surfactants to achieve the desired cleaning and foaming properties. Several thermodynamic and transport properties of surfactant solutions are affected by the size and shape of micelles. Only surfactant monomers contribute to lowering the surface and interfacial tension, while wetting and foaming properties are governed by the concentration of free monomers in solution. The success of surfactants formulation in a liquid soap is reflected on physical stability of the final product, mildness, wetting, foam volume and foam stability. Furthermore, this study reveals that when amphoteric and nonionic surfactants are used with anionic surfactants, foaming of the formulations are improved. Amphoteric surfactants have antibacterial properties, low toxicity, excellent resistance to hard water, and is suitable with various kinds of surfactants. Mixing anionic and cationic surfactants is not recommended. The aim of this paper is to show the influence of individual surfactants and their mixtures on the final properties of liquid soaps as well as the antimicrobial activity of surfactants and the advantages of biosurfactants. The highest antimicrobial activity is reported for surfactants containing 10-14 carbon atoms in their chain. The toxicity of cationic surfactants is the highest, then follow anionic and the last one is nonionic. Biosurfactants show the same functionality as the chemical synthetized surfactants, but biosurfactants are more environmentally friendly, with lower toxicity and biodegradable ability.