The Effect of Fatty Alcohols and Valeric Acid on the Regions of Existence of a Three-Phase System Containing Water, Oil, and Surfactant

For different water–oil–surfactant systems with added aliphatic alcohols and valeric acid, conditions for the formation of the microemulsion (third) phase containing approximately equal amounts of oil and water were determined. It was established that the microemulsion phases are formed in the initial two-phase system (oil-in-water microemulsion–oil) on adding alcohols or the acid, which can be more hydrophilic or more hydrophobic than micelle-forming surfactants. Concentrations of alcohols necessary for the transformation of the three-phase system into the two-phase one were determined. The influence of energy parameters of surfactants and structural characteristics of the alcohol and basic micelle-forming surfactant on the stability of the three-phase system is discussed.