Radiative Cooling Nanohybrids with Room-Temperature Switching

Recent advancements in radiative cooling technologies have highlighted their potential as sustainable and environmentally friendly cooling solutions. However, while this method offers significant energy savings during hot seasons, it may incur energy losses (overcooling leads to a waste of cooling energy) in colder conditions. The current solution has the problems of a complex process or easy leakage of materials. To address this challenge, we synthesized a SiO₂ nanohybrid (a SiO₂ nanoparticle with elongated polymer chains grafted onto its surface), which modifies the thermoresponsive behavior of radiative cooling composites. Upon incorporation of these nanohybrids into the radiative cooling matrix, it will display significant morphological changes in response to temperature variations, leading to changes in the emissivity of the resulting composite film. What's more, the reflectivity of the composite film was enhanced from 57.26 to 89.37%, increasing the cooling performance by 4 °C in hot weather. Results confirmed that the composite film maintained structural integrity without leakage, demonstrating a robust durability. Overall, the synthesized SiO₂ nanohybrids in this work will offer valuable insights for advancing radiative cooling applications.