Biomimetic peptoid-assisted fabrication of antibiofouling thin-film composite membranes

Polyamide (PA) thin-film composite (TFC) membranes are extensively used in water purification but suffer from chronic biofouling, which has spurred extensive research on the development of antibiofouling membranes. In this study, we present a facile method to fabricate a biofouling-resistant, high-performance PA TFC membrane by adding a biomimetic antimicrobial peptoid (i.e., oligo-N-substituted glycines) to the reaction medium during an interfacial polymerization (IP) process. The amphiphilic peptoid facilitates IP by acting like a surfactant, thereby enabling the formation of a highly crosslinked and permeable PA separation layer. Consequently, the peptoid-added TFC (pept-TFC) membrane exhibits superior separation performance compared with pristine, commercial, and other laboratory-made TFC membranes. Furthermore, because the peptoid is strongly incorporated into the PA separation layer network, the resultant pept-TFC membrane is endowed with excellent antimicrobial and antibiofouling properties. Importantly, the enhanced separation and antibiofouling performances of the pept-TFC membrane persist during long-term membrane operation, indicating the robust implantation of the peptoid and permanent changes in the structure and properties of PA. The proposed strategy provides a versatile and environmentally benign platform for fabricating functional membranes by simply employing structurally tailored peptoids with specific functions.