Robust and Sprayable Superhydrophilic/Air-Superoleophobic Fluoroethylene-(hydroxyalkyl) Vinyl Ether Composite Coating for Efficient Antiwaxing Performance in Crude Oil Transportation

Wax deposition in crude oil production is prejudicial to transportation efficiency and can even cause substantial safety hazards in practical operations. Antiwaxing superhydrophilic polymer coatings are promising materials that have attracted widespread attention in both fundamental research and industrial applications. In this study, a robust superhydrophilic/air-superoleophobic composite coating with excellent antiwaxing properties was constructed via a simple spraying method by in situ hybridizing tetraethyl orthosilicate (TEOS) and fluoroethylene-(hydroxyalkyl) vinyl ether (FEVE) resin through a sol–gel process, followed by the incorporation of a fluorinated modifier (FS-50) and diatomaceous earth (DIA) to build hierarchical micro/nanostructures composed of interwoven porous channels and flake-like networks. The wax detachment force of the FEVE@F-SiO2/DIA coating decreased significantly from 40.745 to 1.332 N due to the stable air cushion captured by the hierarchical micro/nanostructures with low-surface-energy groups, which effectively repel wax crystals by minimizing solid–wax interactions. Moreover, the prepared coating demonstrated an outstanding wax inhibition efficiency of 99.69% in underwater conditions, which can be ascribed to the synergistic effect of the hydrated layer anchored by the polar terminal functional groups (−COOH, −NH−) of FS-50 and the fluorine-containing functional groups (−CF2, −CF3) at the nonpolar terminal, preventing wax crystal aggregation and adhesion. Meanwhile, the final coating exhibited remarkable mechanical robustness, maintaining its superwettability with a water contact angle of 0° and an oil contact angle greater than 150°, even after 500 abrasion cycles under a 250 g load. Additionally, the prepared coating exhibited outstanding chemical stability against acids, bases, salts, UV exposure, high temperatures, and prolonged aging. This environmentally adaptive and durable antiwaxing coating offers a practical and effective solution for long-term wax mitigation in oil and gas transportation systems.