Relaxation of numerical limitations for droplet-formation dynamics in orientational ternary systems

Abstract

We construct the Landau-Maier-Saupe (LMS) model by applying a Landau expansion to the isotropic part of the free energy of the previously proposed Flory-Huggins-Maier-Saupe (FHMS) model, in order to relax its numerical restriction. The FHMS model exhibits a rapid droplet formation due to molecular orientational effects, whose dynamics is governed by the Cahn-Hilliard-Cook equation. The numerical restriction inherent in the FHMS free energy limits simulations to a very early stage of the rapid droplet formation dynamics. The LMS model reproduces the rapid droplet formation of the FHMS model and enables phase separation simulations over longer times. Furthermore, long-time simulations clarify the range of applicability of the LMS model.