Multipurpose of Zwitterionic Poly(imidazolium)-Based Hydrogel Coating for Oil/Water Separation with Long-Term Antibiofouling Property

Hydrogel coatings have been applied to separate oil/water mixtures with low oil fouling property. However, most contemporary hydrogels have a short lifespan because of their poor antimicrobial and anti-biofouling ability. Zwitterionic polymeric materials have shown their potential to inhibit microbe (e.g., bacteria) adhesion and can deactivate bacteria by cationic moieties in zwitterion. Herein, we developed a zwitterionic poly(imidazolium) (ZPIM)-based hydrogel coated stainless steel mesh (SSM) with superhydrophilicity and underwater superoleophobicity. The 3D hydrogel network was constructed via cross-linking chitosan with the Debus-Radziszewski reaction, which resulted in the formation of poly(imidazolium) chain. Moreover, PVA and diatomite were also introduced to improve the mechanical property of ZPIM hydrogel coating, resulting in outstanding stability and endurance under harsh conditions. Finally, the ZPIM coated SSM demonstrated high water flux and oil separation efficiency (>99.5 %) as well as superb antibacterial and anti-biofouling activity against both Gram-positive and Gram-negative bacteria. Overall, the study of ZPIM hydrogel coating revealed a new technique for fabricating oil/water separation materials for practical application with low in cost, effective in preparation and excellent bio-fouling resistance.