High-Durable, Radiative-Cooling, and Heat-Insulating Flexible Films Enabled by a Bioinspired Dictyophora-Like Structure.

Abstract

Radiative cooling, achieved by selectively emitting thermal radiation to outer space, holds great promise for addressing global energy challenges and mitigating the effects of climate change. However, most radiative cooling materials face limitations in effectively cooling in high-heat environments, and their performance deteriorates significantly with prolonged outdoor use. These shortcomings restrict their widespread application in various settings. To address this, we draw inspiration from the unique biostructure of dictyophora and propose a novel hollow@porous radiative cooling film by integrating hollow microparticles and porous polymer. The fabricated hollow@porous flexible film exhibits high sunlight reflection (93.7%), strong infrared emissivity (89.1%), as well as ultralow thermal conductivity (17.56 mW/m k). The daytime cooling performance of the prepared cooler is experimentally demonstrated with a marked temperature decrease to 17.4 °C under a peak solar intensity of 980 W/m2. Furthermore, the unique hollow@porous structure also strengthens the film's long-term durability by incorporating weather resistance and self-cleaning properties, which ensures stable and efficient radiative cooling performance even in harsh climatic conditions. This advancement in radiative cooling materials opens up new possibilities for thermal management, energy conservation, and cooling of solar panels, engine components, electronic equipment, new energy batteries, etc.