Two Types of Phase Behavior in a Water/Nonionic Surfactant/Triglyceride System

Abstract

Two types of phase behavior were observed in a water/nonionic surfactant/triglyceride sys-tem. One type was the same as that noted in a water/nonionic surfactant/hydrocarbons system in which a surfactant phase, D, coexists with excess water and oil phases at a certain temperature. The other type was typically observed in a water/nonionic surfactant/amphiphilic oil such as long-chain alcohols. That is, a lamellar liquid crystal coexists with an oil phase at lower tem-perature. With increase in temperature, liquid crystals melt and the melted phase (another sur-factant phase, D') forms a three-phase region together with the water and oil phases. Each of these two types of phase behavior is dependent on the types of surfactant and triglycerides and can be changed by addition of propanol.