Biobased Boston Ivy-Inspired Cryogel Integrating Radiative Cooling and Phase Change Energy Storage for Adaptive Thermal Regulation.

Boston ivy is a traditional plant for building heat management through shading and transpiration. Inspired by its "vine-leaf" system, we design a bionic cryogel that functionalizes daytime cooling and nighttime thermal buffering, promoting sustainable and comfortable housing and living environments. The aligned channels mimic vine tendrils, delivering an ultralow radial thermal conductivity (0.035 W m-1·K-1), high solar reflectance (95.28%), and high infrared emissivity (97.04%). Embedded phase-change materials (PCMs) present leaf-like, functionalized structures that store excess solar energy during the daytime and release latent heat at night, achieving 6.2°C sub-ambient cooling under sunlight. In darkness, the stored latent heat is released, keeping the cryogel 2.4°C above ambient and preventing nocturnal overcooling. This spatiotemporal synergy between daytime radiative cooling and nighttime heat release enables climate-adaptive thermal management, reducing the urban heat buildup with no need for electricity consumption. Our bionic design shifts thermal regulation from passive adaptation to active thermal planning using low carbon footprint materials as proven by life cycle assessment (LCA), offering a more sustainable pathway for energy-efficient buildings.