Fabrication of low-fouling hollow fiber membranes through the immobilization of amine-functionalized microgels on a blended PES-SMA support

This study presents a novel and straightforward method for fabricating low-fouling hollow fiber membranes by immobilizing amine-functionalized microgels on the membrane surface. Poly( N -isopropylacrylamide)-based microgels incorporating 2-aminoethyl methacrylate hydrochloride were synthesized to introduce amine functionality. The hollow fiber membrane support was fabricated from a blend of polyethersulfone (PES) and styrene–maleic anhydride (SMA), enabling covalent microgel attachment via imide bond formation under mild alkaline conditions, or through the electrostatic interaction between carboxylic acid groups in SMA and amine groups in the microgels. Membranes were characterized by scanning electron microscopy, zeta potential measurements, and pure water permeability, confirming successful microgel immobilization. Antifouling properties were assessed using static protein adsorption and cyclic constant-flux filtration experiments with bovine serum albumin and gelatin. Microgel-coated membranes exhibited markedly improved resistance to both reversible and irreversible fouling compared to unmodified membranes. While enhanced surface charge contributed to electrostatic repulsion in PES-SMA membranes, the superior performance of microgel-coated membranes under near-isoelectric and high-salinity conditions suggests that steric and hydration-layer-based barriers play a dominant role in fouling resistance. These findings underscore the effectiveness of microgel coatings and the versatility of SMA as a functional additive for scalable fabrication of antifouling membranes. • Blending of SMA copolymer facilitates subsequent microgel functionalization. • Immobilization of amine-functionalized microgels without use of harsh chemicals. • Antifouling properties evaluated by cyclic constant flux filtration with BSA and gelatin • Improved antifouling attributed to formation of stable hydration barrier. • Microgel layer remains stable after repeated filtration cycles.