Robust photothermal superhydrophobic coating based on fluorinated epoxy resin and SiO₂/carbon black with highly efficient anti-icing performance

Superhydrophobic photothermal anti-icing coatings represent a crucial strategy for addressing outdoor icing challenges. However, they still face significant challenges regarding long-term durability and large-scale production. In this study, a facile and cost-effective one-step spraying strategy is proposed to construct a robust photothermal superhydrophobic composite coating based on a modified epoxy resin system. By introducing an epoxy oligomer grafted with perfluorodecyltrimethoxysilane and precisely regulating the synergistic ratio of 14 nm nanoscale silicon dioxide and carbon black, a dual-scale hierarchical superhydrophobic structure was successfully fabricated. The silicon dioxide nanoparticles act as physical spacers to effectively suppress carbon black agglomeration, which not only induces a light-trapping effect with an optical absorptance exceeding 96% to enhance solar energy harvesting, but also endows the coating with excellent superhydrophobicity (water contact angle of 169.2°, sliding angle of 1.7°). Owing to the overall homogeneity and structural self-similarity of the composite coating, it exhibits exceptional mechanical robustness and weatherability, maintaining its anti-icing and liquid-repellent functions even after 180 tape peeling cycles, 45 sandpaper abrasion cycles, and 288 h of intense UV aging. Notably, the coating demonstrates superior thermal stability, retaining excellent superhydrophobic characteristics after continuous annealing in a muffle furnace at 200 °C for 7 days, thereby effectively overcoming the industrial bottleneck of performance degradation in photothermal coatings under severe summer sun exposure. In extreme anti-icing tests at −30 °C, The coating significantly reduced the adhesion strength of ice on the aluminum substrate from 80.4 kPa to 21.5 kPa; concurrently, the complete freezing time of water droplets was extended from 27 s on aluminum to 93 s. Under xenon lamp irradiation at 25 mW/cm2, its freezing delay time was prolonged from 46 s on aluminum to 214 s. Under an irradiation intensity of 50 mW/cm2, the coating relies on an efficient interfacial melting mechanism to shed a large 1.5 cm3 ice block in merely 73.3 s. This research provides a novel perspective for the fabrication of low-cost, long-lifespan coatings with active-passive synergistic anti-icing performance for harsh extreme environments.