Light-trapping superhydrophobic coatings with switchable wettability to solve low-temperature anti-icing/deicing and high-temperature overheating problems on surfaces

Excessive ice accumulation can cause significant economic losses and even threaten life safety. Therefore, it is crucial to explore integrated strategies for ice prevention and deicing in order to prevent these losses. In this study, a fluorine-free light-trapping superhydrophobic anti-icing/deicing coating with wettability conversion was prepared using modified TiO₂ and multi-walled carbon nanotubes (MWCNTs). The modified TiO₂ nanoparticles and MWCNTs endowed the coating surface with micro/nano rough structures and photothermal properties. The prepared coating has excellent superhydrophobic properties with a contact angle (CA) of 161.5°, which allows the water droplet to delay freezing for about 19 times longer than that of the bare substrate. Furthermore, even at −15 °C, the droplet can still bounce on the coating surface, preventing water accumulation and freezing. Under simulated solar radiation, the frozen water droplet on the surface can be rapidly melted within 283 s, thanks to the exceptional multiscale topography and outstanding photothermal performance of the coating surface. Surprisingly, the surface can realize a superhydrophobic to hydrophilic wettability transition after 30 min of UV irradiation, and the superhydrophobicity can be restored after stopping UV irradiation, based on which the idea of controlling the surface temperature by adjusting the wettability of the coating has been proposed, which is expected to solve the problem of overheating of the surface due to high temperatures.