Sunlight-activated spinel CuFeMnO₄/carnauba wax composite: Synergistic photothermal-superhydrophobic coating for anti-icing and ultrafast deicing

Ice crystal accumulation threatens the safety of power, aerospace, and transportation infrastructure, driving the need for advanced anti-icing strategies due to the limitations of conventional deicing methods. A photothermal-superhydrophobic bifunctional composite coating was developed by integrating spinel CuFeMnO₄ with bio-based carnauba wax (i.e., CFMO/CW). It exhibits efficient light absorption, achieving over 96.7% absorption across a broad spectral range of 250–2500 nm. The coating achieves stable Cassie-Baxter non-wetting behavior, characterized by a water contact angle (WCA) of 155.0° ± 0.9° and a sliding angle (SA) of 3.2° ± 0.2°. Additionally, it demonstrates a significant 486-fold delay in ice nucleation under conditions of −15 °C, lasting 47,689 s, compared with the bare aluminum (Al) plate (98 s). Under 1-sun irradiation, the coating's surface temperature rises by 65.6 ± 0.9 °C within 600 s, enabling it to melt 4 mm of ice within 120 s for rapid deicing. Additionally, the coating significantly inhibits frost formation by evaporating water droplets at 0.2-sun intensity. The CFMO/CW coating demonstrates excellent environmental durability and mechanical robustness, effectively resisting corrosion from strong acids and bases (pH = 1–13), and 3.5 wt% saline solutions. Even after 60 cm of sandpaper abrasion and 10 cycles of tape peeling, it retains its superhydrophobic surface and low sliding angle. This synergistic system integrates energy-efficient photothermal conversion with passive icephobicity, offering a sustainable and effective alternative to traditional deicing methods for applications in extreme environments, such as power infrastructure and aerospace surfaces.