Bioinspired, All-In-One, and Robust Dynamic Passive Cooler Enabled by Solvent-Induced Self-Assembly for...

Developing passive coolers is a promising thermal management strategy for mitigating severe heat stress and environmental pollution. However, conventional radiative coolers, comprising multilayered and randomly porous structures, face challenges such as specific heat accumulation and compromised mechanical properties. Inspired by the distinctive photonic structure of butterfly wings, we engineered an all-in-one, temperature-adaptive, robust dynamic passive cooler featuring a hierarchically porous network, using a solvent-induced self-assembly strategy to seamlessly graft thermal management materials onto the long nanocellulose molecular chains within an engineered wood template via covalent interactions. The bioinspired dynamic passive cooler (Bio-D cooler) adjusts its performance regarding the ambient temperature via a reversible phase transition. Furthermore, when faced with a high-density heat shock, the Bio-D cooler demonstrates an average temperature drop of 5 °C than conventional radiative coolers, reaching a high cooling power of 130.1 W/m². Moreover, the Bio-D cooler demonstrates a mechanical strength of 42.9 MPa, nearly ten times higher than conventional dynamic passive coolers. The all-in-one, robust Bio-D cooler demonstrates significant potential for temperature-adaptive thermal regulation applications.