Application of hydrophilic–lipophilic deviation formulation concept to microemulsions containing pine oil and nonionic surfactant

Abstract

AbstractThe phase behaviour at 25 °C of surfactant‐oil‐water systems containing pine oil and commercial ethoxylated isotridecanols (nonionic surfactants) is reported. All Winsor phase behaviour types were observed, depending on the surfactant average Ethylene Oxide Number and concentration. The technique used was based on the occurrence of the so‐called optimum formulation at which a bicontinuous microemulsion phase is in equilibrium with excess water and oil, with an associated minimum in interfacial tension. Optimum formulation was found at a zero value of the hydrophilic–lipophilic deviation (HLD), a numerical expression which takes all formulation variables into account. This HLD relationship was used to determine the Equivalent Alkane Carbon Number (EACN) of pine oil and its major components.© 2003 Society of Chemical Industry