Perturbation of a nonionic microemulsion by the introduction of a charged surfactant. I: Light scattering

Abstract A nonionic microemulsion with a small fraction of its nonionic surfactant, Brij 96, replaced by sodium oleate was used to vary the charge on the presumed microemulsion droplets in a controllable fashion. Cloud points and other evidence indicate that the mixed microemulsion was formed. The molecular weight and second virial coefficient of the droplets were measured as a function of added salt and showed that the molecular weight of the ionized microemulsion was only slightly changed from the nonionic case, while the changes in second virial coefficient could be described by a hard sphere plus double-layer potential. The particles were shown to undergo ordering at very low salt concentrations.