A new mechanism of spontaneous emulsification: Relation to surfactant properties

A new mechanism of spontaneous emulsification is described and related to the surfactant phase behaviour and to the molecular architecture. Aqueous solutions of the anionic surfactant AOT are shown to form vesicular phases, due to the fact that the head and tail group of AOT are nearly balanced. When these phases are brought gently into contact with an oil by means of a micropipette, a flow of the surfactant aggregates towards the oil phase is observed. The incorporation of the oil into the surfactant bilayers leads to the formation of oil films within the bilayers that are unstable. The vesicles are consequently destabilized and "explode", thereby dispersing the oil in the aqueous phase.