Butterfly‐Wing‐Inspired Pore Architecture Adaptation for Environment‐Guided Radiative Cooling Film

ABSTRACT With frequent extreme heat events, cooling demand is no longer confined to traditional low‐latitude hot regions. Passive radiative cooling is usually designed to achieve the high reflectivity and emissivity under fixed conditions, whereas actual cooling demand changes with latitude‐dependent thermal boundaries. Inspired by the structural‐spectral distribution rule formed by butterfly‐wings in response to their habitats, this work proposes an environment‐guided gradient porous radiative cooling film design strategy. In the TPU/PMMA/ZrO 2 system, thickness‐direction gradient pore regulates photon transmission, PMMA dispersed‐phase introduces secondary scattering on pore‐walls, and ZrO 2 nanoparticles enhance local optical contrast. The optimized G‐TPU/PMMA/ZrO 2 film achieves 96.4% solar reflectance and 98.5% infrared emissivity, exhibiting the lowest outdoor temperature and highest net cooling power. By adjusting the supercritical CO 2 foaming process parameters, the same material system can form large‐pore‐rich, balanced‐gradient, and dense‐small‐pore‐rich architectures to adapt to different thermal environments. Climate‐chamber tests further verified that the optimal pore structure changes with the external environment. EnergyPlus simulations show that radiative cooling cannot be treated as a universal year‐round cooling surface, while an appropriate cooling method should be selected based on climatic characteristics. This work advances porous radiative cooling from single‐condition performance maximization to structural adaptation for different thermal boundaries within one material platform.