Sequential Functionalization of Poly(vinylidene fluoride) Microfiltration Membranes for Improved Antifouling Performance

ABSTRACT Protein fouling severely limits the performance of poly(vinylidene fluoride) (PVDF) membranes due to their intrinsic hydrophobicity, which promotes fouling adsorption and pore blockage, leading to rapid flux decline. Herein, we report a facile, environmentally friendly surface modification strategy to enhance the hydrophilicity and antifouling performance of PVDF microfiltration membranes using polydopamine (PDA) and glucosamine. A conformal PDA interlayer was first deposited on the membrane surface, followed by glucosamine grafting to form a durable PDA/glucosamine composite coating. Atomic force microscopy (AFM) revealed an increase in surface roughness from 83.7 nm for unmodified PVDF to 96.5and 98.3 nm for PDA‐ and PDA/glucosamine‐modified membranes, respectively. Filtration experiments using pure water and bovine serum albumin (BSA) solutions demonstrated that glucosamine grafting significantly improved membrane permeability and fouling resistance compared to unmodified and PDA‐only modified membranes, achieving a maximum pure water flux of 1423 L/m 2 h and a BSA flux of 1194 L/m 2 ·h. Furthermore, PDA‐based coatings substantially reduced BSA adsorption compared to unmodified membranes and maintained high permeability and antifouling performance over multiple filtration cycles, particularly for PDA/glucosamine‐modified membranes, confirming robust coating stability. Density functional theory (DFT) simulations revealed strong interactions between dopamine and glucosamine, including hydrogen bonding and covalent bonding, which facilitate the formation of durable surface coatings on PVDF membranes and corroborate the observed experimental performance. This environmentally benign and scalable modification strategy offers an effective route to mitigate membrane fouling and enhance the long‐term performance of polymeric membranes for sustainable water treatment applications.