Bioinspired Hybrid Nanostructures for Wax Inhibition Coatings with Superhydrophilicity

Wax deposition is a severe flow assurance problem in the petroleum industry. Superhydrophilic coatings have huge potential in wax inhibition based on the water film theory, but their practical applications are severely limited by their fragile structure and unstable water film. Herein, inspired by the remarkable water management abilities of desert lizards, we fabricated a novel TiO2/diatomite/aluminum dihydrogen phosphate (TiO2/DIA/ADP) superhydrophilic coating with hybrid nanostructures that combined hierarchical protrusion and micro-/nanochannel systems. This bioinspired nanostructure induces a potent capillary effect on water, which, along with hydrogen bonds in hydrophilic composition and coordination bonds contributed by the Ti ion in the tetrahedral environment, established a robust water film on the surface of the coating. The water film imparted underwater superoleophobicity and nearly 100% wax inhibition efficiency. In addition, the interfacial strength of the TiO2/DIA/ADP coating is enhanced by the Ti-O -Si covalent bond and the three-dimensional (3D) cross-linked phosphate network formed through ADP. Consequently, the coating retained excellent underwater oil repellency and wax inhibition efficiency even after being treated with 3.5 wt % NaCl solution and strong acidic as well as mechanical wear resistance in air/water. Thus, this research not only contributes to a comprehensive understanding of the antiwax mechanism based on the water film theory but also provides new insights into antiwax coating with an ultrahigh wax inhibition efficiency in the petroleum industry and durable superhydrophilic coating for applications under harsh conditions.