Qian Liu

Angle-sensitive sunlight absorption in state-of-the-art photothermal anti-icing surfaces becomes an Achilles’ heel: geometric shadowing and Fresnel reflection critically degrade broadband harvesting under oblique (incident light >45°) or low solar irradiation (oC, 0.1 sun, 60° incidence) and sustained superhydrophobicity (156 ± 2° contact angle after 50 freeze-thaw cycles). The surface maintains frost-free operation for over 72 h under a sustained low irradiance of 0.1 sun at −30 °C, while integrating exceptional wear resistance and chemical stability. This geometry-adaptive strategy unlocks omnidirectional photothermal deicing for nonplanar architectures like circuit cables and aerospace pipelines, where conventional surfaces fail under erratic solar angles, a leap toward reliable thermal management in extreme environments.

There is an urgent need to design long-term effective anti-fog coatings to ensure the stabilization of uniform water films on hydrophilic surfaces, considering the impacts of interfacial strength, cyclic drying, and contaminants. Here, we propose an anti-fog strategy that leverages manipulating free volume and hydrogen bonding of hydrophilic networks through the twisted non-coplanar structures, synergized with photothermal effects, to enhance anti-fog efficiency. The introduction twisted non-coplanar structures of 1(2H)-phthalazinone not only significantly enhances the coating’s interfacial stability but also increases the molecular free volume, thereby substantially improving its moisture absorption capacity and extending the anti-fogging duration. The developed coating simultaneously achieves high transparency and efficient solar light absorption in the UV/NIR regions, effectively enhancing photothermal fog prevention and removal. The insights into anti-fog strategy promise to translate the structural free-volume benefits measured in laboratories into real-world applications for long-lasting and stable anti-fog coatings.