Modeling phase inversion using Cahn-Hilliard equations - Influence of the mobility on the pattern formation dynamics

H. Manzanarez (1) , J.P. Mericq (1) , P. Guenoun (2) , J. Chikina (2) , D P Bouyer (1)

1 IEM - Institut Européen des membranes
2 LIONS - Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire

This paper presents a phase-field simulation of phase separation for a polymer/solvent system and aims at investigating in a systematic way the influence of the mobility model on the simulation results. In 2D geometry, the Flory-Huggins theory was used to describe the thermodynamics of the PMMA/cyclohexanol system and four mobility models were tested: a constant model, a slow model, a fast model and a mobility model based on the free-volume theory of Vrentas. The simulated patterns were analyzed by Fourier transform and using Minkowski descriptors. Growth laws deduced from a Fourier Transform of the patterns exhibited that the power laws were ranged between 1/5 and 1/3 depending on the quenching conditions ( and initial composition) and the mobility model. Using the Vrentas mobility model, growth laws of , and were found for initial compositions in the range , and , respectively, whereas due to faster phase inversion dynamics, a growth law close to was simulated for the constant mobility model whatever the quenching conditions ( and initial composition), thus demonstrating the importance to choose an appropriate mobility model for simulating the phase separation of polymer/solvent system.

Mots clés: Phase-field simulation; Cahn-Hilliard model; Mobility; Membranes

Domaines: Matériaux

H. Manzanarez, J.P. Mericq, P. Guenoun, J. Chikina, D P Bouyer. Modeling phase inversion using Cahn-Hilliard equations - Influence of the mobility on the pattern formation dynamics. Chemical Engineering Science, 2017, 173, pp.411 - 427. ⟨10.1016/j.ces.2017.08.009⟩. ⟨cea-01591206⟩