A Robust Superwetting Coating With Hierarchical Porous Gel Networks Structure via Hydrogen‐Bond Cross‐Linking and Coordination‐Driven Assembly

ABSTRACT To alleviate membrane fouling encountered in oil/water separation, which is commonly associated with porous membranes fabricated via conventional nonsolventinduced phase separation (NIPS), a hierarchically porous network‐structured coating with nano‐titanium dioxide particles (TiO 2 ) anchored via hydrogen‐bond crosslinking between polyvinylpyrrolidone (PVP) and tannic acid (TA), using polyethersulfone (PES) as the reinforcing framework featuring superhydrophilicity, underwater superoleophobicity, and robust photocatalytic selfcleaning capability was rationally designed and fabricated. Hereafter, this coating is denoted as (PPTT). The hydrophilic additive PVP and TA form a stable hydrogenbonded crosslinked network in the aqueous coagulation bath, which effectively promotes the formation of a hierarchical porous structure. Moreover, the coordination interaction between TA and TiO 2 nanoparticles further constructs an organic‐inorganic interpenetrating structure, thereby strengthening the structural stability of the membrane. The optimized coated membrane exhibits high separation efficiency and favorable antifouling performance for both oil/water mixtures and surfactantstabilized oilin‐water emulsions. Furthermore, this work extends the application of the PPTT coating to boosted fog water collection, achieving significant performance enhancement. This study provides a strategy for fabricating highly adaptable superwetting coatings via the NIPS method, enabling multifunctional applications in oil/water separation, antifouling, and fog water collection.