Abstract

Microemulsions are thermodynamically stable mixtures of an oil, water, and a surfactant (soap) and often a cosurfactant (alcohol).¹ Such phases are fluid and optically isotropic. It has been shown that diluted microemulsions feature a micellar structure. In the case of water in oil microemulsions, water is under the form of spherical droplets a few nanometers in diameter, isolated from the oil-rich phase by a shell of surfactant molecules (inverted micelles).^1,2 The stability of the system is partly controlled by attractive interactions between the micelles. Critical like behaviors, resulting in a demixing between two identical phases,³ have been reported recently from light-scattering experiments. Critical microemulsions are characterized by the divergence of a number of quantities, such as the correlation length ξ of the fluctuations of the refractive index and the osmotic compressibility κ_T.

© 1984 Optical Society of America