Numerical Simulation of the Phase Separation of a Polymer-Polymer-Solvent Ternary System on a Heterogeneously Functionalized Substrate

The spinodal decomposition of a polymer-polymer-solvent ternary system was investigated in a 3-dimensional numerical model. The Cahn-Hilliard equation was employed to describe the free energy profile of the domain. A heterogeneously functionalized substrate was also implemented into the model to simulate the effect of substrate attraction. The mechanism of the morphology evolution was studied quantitatively. The well established linear relationship of the characteristic length, R(t) with t^1/3 can be observed in the simulation results. The compatibility of the result pattern and the pattern on the substrate was measured by a scalar, C_s. The influence of the solvent concentration on the refinement of the result pattern was studied in this work. A critical time can be observed from the evolution of the value of C_s. The morphology evolution of a system considering the solvent evaporation was also studied.