The swollen micelle-microemulsion transition

Abstract

A rather abrupt transition takes place in the properties of a nonionic microemulsion at a certain value of hexadecane uptake, Wo (the weight fraction of oil plus surfactant that is oil). When Wo is greater than 0.06, the microemulsion behaves as spherical particles that can be diluted with water without change in their properties. The intrinsic viscosity, Huggins coefficient, and 4A2Mw have values close to those observed for the globular proteins. When Wo is less than 0.06 the particles are anisotropic in shape, as shown by classical light scattering. Moreover, the anisotropic particles are undergoing open association so that dilution decreases their average size. When diluted, the rate of oil uptake by the microemulsion is orders of magnitude smaller than for the swollen micelles. © 1983.