Aggregation models at high packing fraction

Abstract

Dense phases of micellar aggregates have strong molecular correlation at two different levels: that of the molecules forming a micelle and that between micelles, leading to a possible phase transition from a micellar fluid to a micellar crystal. The global phase diagram may also include lamellar and other dense phases, which do not have a micellar structure. We present here a generic approach to deal with these systems through a two-level density-functional description, to first describe an isolated micellar aggregate and then the dense micellar system, obtaining the free energy in a self-consistent way from the molecular interactions. Nonmicellar dense phases are included with the same density-functional approach applied at the first level. The results are shown to be very accurate for a one-dimensional model with exact solution, and the method is then applied to a three-dimensional amphiphile model that had been successfully used to describe the properties of diluted amphiphile solutions.