Ester Bond-Anchored TMP Moieties for Durable and Rechargeable Anti-biofouling PVDF Membranes

Global water scarcity and pollution have elevated membrane separation to an indispensable technology for sustainable water purification. Poly(vinylidene fluoride) (PVDF), prized for its exceptional chemical and mechanical stability, faces a long-standing performance trade-off, as its inherent hydrophobicity causes severe biofouling, while chlorine regeneration for biofilm removal degrades surface-grafted antibacterial functional layers. Herein, we report a high-performance chlorine-rechargeable N-halamine antibacterial membrane (denoted as PPVDF-O-TP-Cl, a PEG-blended PVDF grafted with chlorinated TMP moieties) fabricated via an integrated "passive defense-active attack" strategy, featuring covalent surface anchoring of sterically hindered 2,2,6,6-tetramethylpiperidine (TMP-OH) onto PVDF backbones through ester linkages. The membrane achieved robust broad-spectrum antibacterial efficacy, delivering a 6.1-log reduction against Gram-negative E. coli and a 5.5-log reduction against Gram-positive S. aureus within 30 min, a flux recovery ratio exceeding 90.0%, and retained over 99% antibacterial activity after 10 chlorination-regeneration cycles. Notably, TMP's bulky methyl groups sterically shield vulnerable ester bonds from hydrolytic and oxidative degradation, while PEG hydration layers and N-halamine moieties synergistically mitigate the interfacial kinetic imbalance plaguing traditional membranes. This work provides a versatile strategy for designing durable rechargeable anti-biofouling membranes, with future investigations warranted into their long-term performance in complex real wastewater matrices and scalable fabrication.