Abstract: A superhydrophobic coal gangue photothermal coating is prepared by in-situ modification of coal gangue through the Michael addition reaction of dodecylamine (DDA) and dopamine (DA). This coating has excellent anti-icing and de-icing properties, providing a new solution for the modification and resource utilization of coal gangue waste. The results show that the photothermal synergistic effect of coal gangue and polydopamine enable the surface temperature of the coating to reach 90.2 ℃ (1 kW/m2). At the same time, due to the synergistic effect of the multi-scale structure and low surface energy alkyl long-chain, the coating surface exhibit a water contact angle of up to 157 °± 0.8 ° and a sliding angle of 3.2 °± 0.3 °. In a low-temperature environment of -15 ℃, the freezing delay time of water droplets on the coating surface is 38.3 times that of uncoated material. In addition, due to the photothermal conversion characteristics of the coating, the ice on the surface of the coating can quickly melt in just 120 s under 1 kW/m2 of light illumination, demonstrating its excellent passive anti-icing and active de-icing performance. Importantly, the coating also has excellent self-cleaning performance, mechanical stability, and chemical stability. This multifunctional photothermal coating has important application prospects in the high-value utilization of coal gangue and green protection of engineering materials.

Key words: Coal gangue modification; Photothermal conversion, Superhydrophobic coating, Anti-icing