An anisotropic immerse precipitation process for the preparation of polymer membranes

We study the immerse precipitation process in a ternary polymer/solvent/non-solvent system by numerically solving the two-dimensional Cahn-Hilliard phase field equation. In particular, we introduce anisotropic mobility, namely the mobility of a polymer varies over different spatial directions, and focus on the porosity morphology of the obtained polymer membrane. Simulations reveal that as the anisotropy increases in the polymer mobility, the polymer pattern changes from nearly isotropic and random voids to strips parallel to the direction with smaller mobility. The influence of anisotropy quickly saturates. The anisotropic mobility model is also applied to a ternary system mimicking the preparation of a hollow fiber membrane, and shows strong effects on the membrane porosity pattern.

Automated summary

In this study, we investigate the precipitation process in a ternary polymer/solvent/non-solvent system by numerically solving the Cahn-Hilliard equation. The anisotropic mobility of the polymer is introduced and its effects on the porosity morphology of the polymer membrane are investigated. The results show that the anisotropy in polymer mobility leads to changes in the polymer pattern and influences the porosity structure of the membrane.