Preparation of gradient porous polymer membranes with multifunctionality†

Abstract

Porous membranes have attracted considerable attention in materials science. It is crucial to develop a simple strategy for multifunctional porous membranes with broad applications. Herein, gradient porous membranes were prepared from a poly(ionic liquid) (PIL) of poly[3-cyanomethyl-1-vinylimidazolium bis(trifluoromethane-sulfonyl)imide] and the natural small molecule of α-thioctic acid (TA) using a combination of solution mixing, ring-opening polymerization (ROP) and post-processing. The resulting membranes of PIL/PTA with gradient pores were confirmed by FT-IR, NMR, Raman, and SEM characterizations. Interestingly, PIL/PTA porous membranes are stimulus-responsive materials with self-healing and UV-blocking properties. It is demonstrated that polymer membranes with solvent-stimulated responsiveness depend mainly on their gradient pore structure, which can be used as a highly sensitive solvent sensor. In addition, self-healing and UV-blocking properties have been developed by combining typical features of PIL and PTA into porous membranes. This work is beneficial for the rational design of multifunctional porous membrane materials to meet existing applications.