Coral-Inspired Multi-Scale Porous Particle-Nested Structure for Efficient Colored Radiative Cooling

Passive daytime radiative cooling (PDRC) is one of the most promising ways for energy conservation and even carbon emission reduction to achieve carbon neutrality. However, developing colored PDRC materials that exhibit effective cooling performance while meeting aesthetic requirements for outdoor applications remains challenging. Polymer material with lightweight, low-cost, and universal high thermal emissivity, poses great potential of efficient radiative cooling materials. In this study, a hierarchical pore-particle-nested structure is engineered in a polymer framework, achieving a solar reflectance of 93.6% and a thermal emissivity of 91.1%. Moreover, the colored variants maintained high performance, with solar reflectance values of 80.6%, 84.8%, and 88.1% for the blue, pink, and yellow films, respectively. The pore-particle-nested structure enhances scattering of both direct and diffuse sunlight, enabling efficient colored PDRC films. With enhanced mechanical properties and hydrophobic performance, the structure provides a cost-effective strategy for developing practical outdoor PDRC materials.