3D Printing of a Durable Superhydrophobic Film for Daytime Radiative Passive Cooling and Water Harvesting.

Superhydrophobic passive cooling materials offer a promising solution to reduce energy consumption during extremely hot days due to their self-cleaning properties, which prevent dust contamination and extend their cooling lifetime. However, achieving a comprehensive performance, including mechanical durability, resistance to strong acid/alkali corrosion, thermal stability, and UV radiation tolerance, remains a significant challenge. Herein, a durable superhydrophobic film exhibiting remarkable durable superhydrophobicity against the above conditions for daytime passive cooling and water harvesting was prepared based on UV-cure 3D printing and postpainting modification. The obtained film showed outstanding self-cleaning properties even after being immersed in aqueous solutions with pH values of 2-12 for 24 h. Compared with ambient air, the passive cooling results demonstrated that the film achieved a maximum temperature reduction of approximately 21 °C, and the film successfully reduced the maximum roof temperature of a wooden house model. Additionally, the film exhibited promising water harvesting capabilities with a water collection rate of 2018.5 ± 84.9 mg cm-2 h-1. Overall, this work not only introduces a straightforward method to prepare durable superhydrophobic films but also offers innovative materials for addressing energy consumption and water scarcity challenges.