Vector lattice model of amphiphilic mixtures: Interfacial behavior

The interfaces between the water-rich, oil-rich and disordered phases of a balanced ternary mixture of oil, water and amphiphile are studied, on the basis of a vector lattice model, by means of an exact partial integration and a local mean field approximation. The phase diagram exhibits a water/oil-rich phase, structured (ordered bicontinuous and lamellar) phases and a disordered phase with a microemulsion region. The interfacial tension and profiles at oil/water/disordered phase coexistence are calculated and the possibility of a wetting transition is discussed.