MICROEMULSIONS - INTERFACIAL ASPECTS

We recall the basic theoretical knowledge on microemulsion structure emphasizing the importance of the surfactant layer properties. We show the close relationship between the maximum characteristic size in the microemulsion (maximum solubilization power) and the persistence length of the surfactant layer. We discuss the range of surfactant layer bending elasticities in which microemulsions can be formed: when the elasticity is too large, ordered phases (lamellar, cubic...) are obtained; when it is too small, the surfactant film cannot form, and the medium is a structureless molecular mixture. We also discuss the relation between the surfactant layer properties and the interfacial tensions between the microemulsions and other coexisting phases.