Synergism and Performance Optimization in Liquid Detergents Containing Binary Mixtures of Anionic–Nonionic, and Anionic–Cationic Surfactants

In this paper evaluation of surface active and application properties in liquid detergent formulations containing binary mixtures of anionic–nonionic, and anionic–cationic surfactants is discussed. Surfactants used include: linear alkylbenzene sulfonate (LAS), alcohol ether sulfate (AES-2EO), alcohol ethoxylate (AE-7EO), lauryl dimethyl amine oxide, and alkyl hydroxyethyl dimethyl ammonium chloride (AHDAC). Surface active parameters relating to the effectiveness and efficiency of surface tension reduction were determined from the surface tension data. Non-ideal solution theory was used to determine the degree of interactions between the two surfactants, and the conditions under which a mixture of two surfactants show synergism in surface active properties. Our data indicated that synergism in mixed surfactants increases with the degree of charge difference between the surfactants. In both mixed micelle and mixed monolayer formation, the degree of interactions between the two surfactants in the mixture increased in the following order: LAS/AE < AES-2EO/amine oxide < AES-2EO/AHDAC. This synergistic behavior as presented in this paper leads to unique application properties and improved performance in terms of foam volume, and soil removal which has applications in formulation of dishwashing liquids, and laundry detergents.