Spontaneous Emulsification in OIL-WATF.R.-SURFACTANT Systems*

Mixtures of several alkl-aryl sulfonates with brine were carefully contacted with oil. The mixtures contained a few percent surfactant and were either liquid crystalline phases or dispersions of liquid crystalline particles in brine. At high salinities a brine layer developed between the initial phases and an emulsion of brine drops in oil formed spontaneously at discrete sites along the surface of contact. At low salinities no emulsifixation was seen. The occurrence of emulsification only at high salinities is explained in terms of local supersaturation produced by the diffusion process.