A STUDY OF THE PHASE-DIAGRAM OF THE MICELLAR BINARY-SOLUTION MODELS .1. MEAN-FIELD APPROACH

The mean field approximation is used to investigate the phase diagrams in a three-dimensional lattice of micellar binary solutions in the pr esence of a chemical potential of the amphiphiles for different values of coupling interactions. New phases appear between the water-rich an d amphiphile-rich ones. Second and first order transitions, tricritica l, multicritical and critical end-points are obtained. By a simple low temperature expansion argument, we have confirmed the existence of st ates of lowest free energy via mean field approximation.