Engineering polyamide nanofiltration membrane with bifunctional terpolymer brushes for antifouling and antimicrobial properties

In order to alleviate the organic/biological membrane fouling, we propose a difunctional nanofiltration membrane with integrating antifouling and antibacterial properties. In this work, the random terpolymer containing quaternary ammonium and zwitterionic moieties is fabricated via free radical polymerization and followed by grafting on the surface of nanofiltration membrane via coupling reaction. Surface characterization demonstrates the enhanced hydrophilicity and higher surface charge after the membrane modification. Benefiting from the co-existence of quaternary ammonium and zwitterionic moieties on the membrane surface, the terpolymer-modified membrane (i.e., TP-TFC) can not only effectively inhibit the protein and bacterial adhesion, but also possess high bacteria inhibiting efficiency. In the protein/bacterial dynamic fouling test, the water flux maintenance and flux recovery of TP-TFC membranes are among the best, which is of great significance for the long-term antibacterial properties. Results reported here shed light on a novel approach for fabricating the antifouling and antimicrobial nanofiltration membranes.