A hydrophilic and antiwax coating with stable fly ash-based coral-like 3D skeleton construction

Wax deposition constitutes a severe flow assurance challenge in the petroleum industry. Hydrophilic coatings show great potential for wax inhibition based on the water film theory. Herein, we report a novel silica-modified fly ash/aluminum dihydrogen phosphate (FA@SiO2/ADP) hydrophilic coating with hybrid micro/nano-architectures. The introduced hierarchical structures induce strong capillary action toward water, while abundant surface hydroxyl groups and phosphate networks facilitate the formation of a stable and continuous water film via hydrogen bonding and covalent P–O–Si cross-linking. This results in outstanding underwater oleophobicity and wax inhibition efficiency of 51.2%. Furthermore, the coating exhibits significantly enhanced interfacial strength and mechanical robustness due to the inorganic ADP binder and the formation of network structure. This work not only provides a practical and cost-effective antiwax coating with promising industrial applicability but also offers deeper mechanistic insights into the design of durable hydrophilic surfaces for harsh operational environments.