Surface modification of PVDF membrane by physical co-deposition and bridging grafting strategy for enhanced anti-fouling performance

Polyvinylidene fluoride (PVDF) has emerged as a prominent ultrafiltration (UF) membrane material owing to its exceptional chemical resistance, superior mechanical strength, and remarkable thermal stability. Nevertheless, its widespread application is constrained by inherent limitations, notably its pronounced hydrophobicity and suboptimal anti-fouling performance. In this work, we introduced an innovative approach combining physical co-deposition and bridging grafting technique to fabricate supramolecular hydroxyl bundles on PVDF membrane surface, thereby enhancing both hydrophilicity and anti-fouling performance. The PVDF/styrene-co-maleic anhydride (SMA)-g-polyethylene glycol (PEG)-g-polyvinyl alcohol (PVA) membrane was prepared through our novel grafting approach. We systematically investigated the formation and evolution of the grafted membrane surface, focusing on chemical structure and surface morphology at varying concentrations. Our results demonstrated that this method significantly improved membrane hydrophilicity, consequently enhancing its anti-fouling performance. Furthermore, we examined the correlation between membrane surface morphology and its permeability and anti-fouling performance. The implementation of the supramolecular hydroxyl bundle isolation layer (SHBIL) has shown remarkable improvements in anti-fouling performance, achieving a bovine serum albumin (BSA) rejection rate exceeding 97% at an optimal PVA concentration of 8%. This research provides valuable insights into the hydrophilic modification of PVDF membrane with superior anti-fouling performance and presents a novel perspective for understanding the underlying anti-fouling mechanism.