Surface modification of ultrafiltration membranes by grafting glycine-functionalized PVA based on polydopamine coatings

•Glycine-functionalized PVA was synthesized and grafted on PD-coated UF membranes.•The modification of PD-g-PVA reduced the surface roughness of membranes significantly.•The grafted PVA layer was fairly stable in acid and alkaline conditions.•The modification of PD-g-PVA improved the antifouling ability of UF membranes. Due to the ease of processing and stability during filtration, polydopamine (PD) coatings with grafted hydrophilic polymers have recently received significant attention. In this study, glycine-functionalized PVA was synthesized and grafted to a PD-coated ultrafiltration (UF) membrane to improve its performance during wastewater filtration. The membranes were modified by grafting PD with glycine-functionalized PVA (PD-g-PVA), and the resultant materials were characterized using surface morphology analyses, contact angle measurements, flux, oil/water emulsion separation tests, and grafted layer stability tests. The performance of the PD-g-PVA membrane was compared to that of the membrane modified with PD-g-polyethylene glycol (PEG). After grafting the PD-g-PVA, the surface roughness of the membranes decreased significantly. The grafted PVA layer, which was stable under acidic and alkaline conditions, protected the PD layer. The filtration experiments with an oil/water emulsion indicated that modifying the glycine-functionalized PVA by grafting can significantly improve the antifouling ability of membranes.