Antibiofouling\nPolyvinylidene Fluoride Membrane Functionalized\nby Diblock Copoly(ionic liquid) Brushes

Abstract

To combat membrane biofouling, diblock\ncopoly(ionic liquid)\nmembranes\n(PIL-M) with the controlled structure were prepared by introducing\ncationic and anionic PIL brushes on the PVDF membrane by secondary\natom transfer radical polymerization (ATRP). The antibacterial performance\nand hydrophilicity of the membranes were optimized by adjusting the\norder of the cationic and anionic PIL brush layers. The chemical composition\nand morphological characterization of diblock PIL-M membranes demonstrated\nthe feasibility of the diblock modification by the ATRP method. The\ndiblock PIL-M membranes exhibited broad-spectrum antibacterial activity,\nvarying in effectiveness depending on the functionalized structure.\nAmong them, the membrane with a bottom anionic PIL brush layer and\nsurface cationic brush layer (C₁₂-TA-M) had the best bacterial\ninhibition effect, which could be as high as 92.0%. Moreover, the\ndiblock PIL-M membranes possessed improved biofouling resistance during\nthe dynamic filtration, and the C₁₂-TA-M membrane showed\na 51.4% increase in biofouling resistance compared to the pristine\nPVDF membrane. Characterization of surface energy and interaction\nenergy of functionalized membrane demonstrated that the introduction\nof a hydrophilic anionic PIL brush layer can further enhance the antiadhesive\nability of the modified membrane. This study provides an effective\nstrategy to design and prepare ionic liquid-based antifouling membranes\nand verifies its potential applications in water or wastewater treatment.