Robust surface stability and enhanced anti-fouling property on PVDF ultrafiltration membrane surface: PDA/PEG co-deposition versus traditional PDA coating

Abstract

Membrane surface design, especially for the anti-protein fouling property, is vital for the development of synthetic polymer ultrafiltration membranes. Although mussel-inspired antifouling coatings have obtained rapid development, the surface chemical adhesion stability still suffers from weak chemical stability especially in strongly alkaline environment. In this paper, the surfaces of polyvinylidene fluoride (PVDF) membranes were modified via traditional polydopamine (PDA) coating followed with polyethylene glycol (PEG) immobilization method and PDA/PEG co-deposition strategy. In contrast to general PDA coating, the fabricated membrane surface exhibits excellent chemical adhesion stability under the different solution environment (whatever in neutral deionic water solution, acidic solution (pH=2) or strongly alkaline solution (pH=14)). The membrane surface elementary composition and morphologies were evaluated by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The modified membranes obtained via co-deposition were confirmed to have excellent hydrophilicity, enhanced coating stability and good dynamic/static anti-protein adhesion properties. Overall, this work provides a facile, robust and useful bio-inspired anti-fouling membrane surface modification strategy for broadening the application in water treatment field of ultrafiltration membranes.