A MODEL FOR MEMBRANES, VESICLES AND MICELLES IN AMPHIPHILIC SYSTEMS

We present a microscopic model for the aggregates of amphiphilic molec ules, based on a simple density functional approximation for the free energy. The different molecular aggregates are described as self-struc tured density distributions at the relative minima of the grand potent ial energy. We search for these structures with planar and spherical g eometries, and obtain the phase diagram for bilayer membranes, and the curvature energies for vesicles and different types of micelles. The study of a global phase diagram, to get the density of micelles and is olated amphiphilic molecules, at equilibrium with free membranes, requ ires the link between two description levels of micelles: as self-stru ctured density distributions, or as molecular clusters in the solution of amphiphilic molecules in water. This is done with the help of a si mple harmonic model which provides an appropriate choice of the config urational unit cell for micelles.