Bio-inspired Tough Metafiber with Hierarchical Photonic Structures for Durable Passive Radiative Thermal Management

Passive radiative thermal management holds substantial potential for enhancing energy efficiency and sustainability. However, few research efforts have addressed the integration of mechanical robustness and durability with the distribution and composition of photonic structures within materials. Silk fibers, known for their distinctive hierarchical morphological structure, offer a solution to these challenges by providing exceptional optical and mechanical properties. Inspired by this, we developed a silk-like tough metafiber (PMABF) that incorporated multiple scatterers through a multi-scale structural construction of nanofiber aggregates and molecular interface engineering. We show that fabrics woven with PMABF can provide high mid-infrared (MIR) emissivity (98.6%) within the atmospheric window and 86.7% reflectivity in the solar spectrum, attributed to its ellipsoidal photonic structure featuring by surface micro-/nano-particles and numerous internal voids. Through mature and scalable industrial manufacturing routes, our metafibers show excellent mechanical strength, hydrophobicity and thermal stability while maintaining effective passive radiative cooling. Practical application tests demonstrated that molecules introduced during the heterogeneous composite process significantly enhanced the metafiber’s tensile strength (125%) and compressive stress (261.5%) by forming junction welds among the nanofiber backbones to efficiently distribute the external forces. Furthermore, the superior thermal stability and flexibility of PMABF open abundant opportunities for diverse applications with demanding thermal management requirements, such as thermal protection and multi-scenario thermal camouflage. Graphical