Stimuli-Responsive Membranes through Sustainable Aqueous Phase Separation

Joshua D. Willott, Wouter M. Nielen, Wiebe M. de Vos*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Polymeric membranes are used on huge scales for kidney dialysis, wastewater treatment, and drinking water production. However, almost all polymeric membranes are fabricated by a process reliant on the use of unsustainable, expensive, and reprotoxic dipolar aprotic solvents. In this work, we propose an aqueous phase separation approach for preparing porous membrane films. Poly(4-vinylpyridine) (P4VP), a pH-responsive polymer, is first dissolved at low pH where the polymer is charged and subsequently cast as a thin film. Switching to a high pH where the polymer is uncharged and insoluble results in controlled phase separation and solidification of the polymer into porous membrane structures. This approach gives a large degree of control over membrane structure, leading to symmetric porous microfiltration membranes and asymmetric dense nanofiltration membranes. Moreover, the use of a pH-responsive polymer leads directly to a pH-responsive membrane, where the degree of responsive behavior can be tuned by the degree of cross-linking. Such responsive behavior allows effective cleaning of the membrane, without the use of harsh chemicals. This work outlines an approach toward preparing membranes in a more sustainable fashion—an approach that allows control over the membrane structure and one that naturally leads to advanced membranes with responsive properties.
Original languageEnglish
Pages (from-to)659-667
JournalACS Applied Polymer Materials
Issue number2
Early online date3 Dec 2019
Publication statusPublished - 14 Feb 2020


  • UT-Hybrid-D
  • polyelectrolytes
  • membranes
  • stimuli-responsive
  • nanofiltration
  • non-solvent-induced phase separation
  • aqueous phase separation

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