Fabrication of Oligoaniline-Based Electrically Responsive Polyamide Membranes for High-Performance Molecular Nanofiltration

Abstract

Smart responsive nanofiltration (NF) membranes generated widespread interest for their ability to dynamically regulate permselectivity during operation according to the requirements of the separation. However, the reported smart membranes were usually impeded by limited stability as the problem of compatibility between conductive materials and a polymer membrane. Herein, we report a high-performance electrically responsive polyamide (PA) membrane for molecular NF by introducing an oligoaniline of amino-capped aniline trimer (AT) involved in the formation of a PA membrane. The membranes were prepared via interfacial polymerization (IP) of AT and trimesoyl chloride (TMC) on a porous substrate. The influence of AT, TMC, and dopant of the AT concentration on the membrane performance was systematically investigated. The results demonstrate that the introduction of AT significantly enhances the molecular separation performance of the membranes. The fabricated membranes exhibit excellent rejection toward small organic molecules while maintaining high water permeance and excellent long-term stability. Moreover, the membranes show remarkable electrocyclic responsiveness, allowing for effective control of the rejection rate by applying an external electric field. The improved performance of the membranes is attributed to the unique electrical and structural properties of AT doping by ionic liquids. Our findings provide valuable insights for the development of high-performance molecular nanofiltration membranes.