Immobilization of poly(N-acryoyl morpholine) via hydrogen-bonded interactions for improved separation and antifouling properties of poly(vinylidene fluoride) membranes

Poly(N-acryoyl morpholine) (PACMO), a promising antifouling surface modifier, has many desirable properties including high hydrophilicity, chemical stability, and excellent hemocompatibility. Considering the intrinsic hydrophobic property of most polymer membranes, surface modification by hydrogen bonding self-assembly has garnered intense interest. In this work, a hydrophobic poly(vinylidene fluoride) (PVDF) membrane surface was first dip-coated a polydopamine (PDA) coating and then followed by immobilization of PAMCO via hydrogen-bonded interactions between PACMO and PDA. The mechanism of foulants deposition onto the membrane surface was quantitatively assessed by extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory. The hydrophilic PACMO layer modified PVDF membranes exhibited a simultaneously enhanced permeability, rejection and antifouling property in protein filtration and oil/water emulsion filtration, and humic acid filtration, respectively. Moreover, the as-prepared membranes had prominent long-term stability even in harsh conditions due to strong hydrogen-bonded interactions between PACMO and PDA. This work provided a practical strategy for hydrophilizing membrane surfaces by hydrogen bonding self-assembly.