A Phase-Field Model for the Membrane Formation Process Via Phase Inversion

Phase inversion, a process that occurs when a polymer collapses from solution into a thin film upon quenching or exposure to another phase, is the most widely used process for producing polymer membrane filters. The level of understanding of these manufacturing processes remains mostly empirical, with little theoretical basis to connect the process conditions and important quantitative membrane characteristics. This gap in knowledge necessitates a substantial amount of trial-and-error experimental work to discover and define the “process window” for a particular membrane product, which increases R&D costs and limits innovation of new membrane products or processes. We have developed mesoscopic simulation models to examine the dynamics of the phase inversion process to predict the morphology of pore structures that develop within microporous polymer membrane filters. The computational approach for modeling phase inversion is a novel phase-field method that utilizes the Cahn Hilliard equation that incorporates the thermodynamic and kinetic parameters relevant to phase separation in polymer solutions. The modeling tools developed will enable significant speed-up in membrane development. This talk will focus on initial results of the Cahn Hilliard model and compare simulated structures and morphologies to current manufactured polymer membrane filters.