Keywords

Glass transition, Interfaces, Membranes, Microstructures, Phase separation

Abstract

We report the first simulations of nonsolvent-induced phase separation (NIPS) that predict membrane microstructures with graded asymmetric pore size distribution. In NIPS, a polymer solution film is immersed in a nonsolvent bath, enriching the film in nonsolvent, and leading to phase separation that forms a solid polymer-rich membrane matrix and polymer-poor membrane pores. We demonstrate how mass-transfer-induced spinodal decomposition, thermal fluctuations, and glass-transition dynamics—implemented with mobility contrast between the polymer-rich and polymer-poor phases—are essential to the formation of asymmetric membrane microstructures. Specifically, we show that the competition between the propagation of the phase-separation and glass-transition fronts determines the degree of pore-size asymmetry. We also explore the sensitivity of these microstructures to the initial film composition, and compare their formation in 2D and 3D.

Original Publication Citation

https://pubs.acs.org/doi/10.1021/acsmacrolett.0c00609

Document Type

Peer-Reviewed Article

Publication Date

2020-10-26

Publisher

ACS

Language

English

College

Ira A. Fulton College of Engineering

Department

Chemical Engineering

University Standing at Time of Publication

Assistant Professor

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