THE EFFECT OF N-BUTYL GLYCOL ETHERS ON THE PHASE-DIAGRAMS OF MICROEMULSIONS FORMULATED WITH NONIONIC SURFACTANTS

The effect of n-butyl glycol ethers used as cosurfactants on the micro emulsions formulated with two nonionic surfactants, hexaoxyethylene gl ycol monolauryl ether and sorbitan monolaurate, is presented on ternar y phase diagrams. The solubilization parameters as well as isothermal invariant points (IIP) of microemulsions were correlated with the solu bility parameters of cosurfactants. An optimum solubility parameter of cosurfactants was established around 9 (cal/cm(3))(1/2) where both II P and solubilization parameters are optimal for water and oil solubili zation with the lowest concentration of amphiphilic compounds. The mix ture of cosurfactants can be used to obtain a certain transition on th e phase diagram and so to achieve certain characteristics for microemu lsions, especially to tailor the solvency of the system.