Low-Temperature-Assisted Interfacial Polymerization Toward Wrinkle-Like Structured Thin-Film Nanocomposite Nanofiltration Membranes

Abstract

Confining the diffusion rate of aqueous amine monomers during interfacial polymerization (IP) via incorporating nanoparticles/macromolecules with special functional groups and/or creating an interlayer owning suitable properties is an attractive alternative to construct a polyamide (PA) nanofilm featuring unique surface morphologies. However, the fabrication of high-performance nanofiltration (NF) membranes with both special structural compositions and ultrathin PA separating layers is still a great challenge. Herein, a highly permeable, loose thin-film nanocomposite (TFN) NF membrane with wrinkle-like structures was fabricated by incorporating Ti₃C₂T_x nanosheets into the aqueous solution via a low-temperature IP strategy. The Ti₃C₂T_x nanosheet hindered the diffusion rate of aqueous monomers toward the reaction zone, whereas the low temperature of the oil phase enabled the confined transfer rate of oil monomers. Thus, the double monomers restricting strategy (DMR) greatly changed the interfacial reaction environment, contributing to forming a sub-15 nm PA film (TFC-Mi) with a wrinkle-structured surface. The TFC-Mi membranes exhibited larger pore size and stronger Donnan exclusion, resulting in 98.6% of Na₂SO₄ rejection and high water permeance of 26.3 LMH/bar. The long-term filtration test further evidenced its great performance stability. The DMR-assisted IP owned great promise in tailoring high-performance loose TFN NF membranes for environmental water applications.