Phase behavior of amphiphile-solvent systems from lattice Monte Carlo simulations

Monte Carlo simulations of a lattice model for amphiphile/solvent systems a re used to obtain data for the configurational energy of mixing. Based on t he simulation results, the energy of mixing is correlated as a function of the interaction energy and volume fraction of the amphiphile using a Redkli ch-Kister correlation. The Helmholtz free energy of mixing is obtained by u sing the Gibbs-Helmholtz relation with the athermal entropy of mixing predi ction from the quasichemical approximation as boundary condition. Using thi s information, an analytic expression for the chemical potential of the amp hiphile and solvent is obtained, and the phase behavior for amphiphiles wit h different structure is obtained. The expressions generated in this work p roduce coexistence curves that are more accurate than those obtained from t he quasichemical approximation. (C) 2001 Elsevier Science B.V. All rights r eserved.