Temperature‐Responsive Resonator Metafabrics for Self‐Adaptive Thermoregulation

Abstract Thermal management plays an indispensable role in the ever‐emerging flexible electronics, as undercooling or overheating can severely impact their performance and longevity. There is growing interest in zero‐energy thermal management skins for electronics. The unidirectional cooling effect of radiative cooling can exacerbate the burden of heating electronics in cold environments. Temperature‐responsive, self‐adaptive thermoregulated sheets leveraging Fabry‐Pérot cavities exhibit limited flexibility, rendering them unsuitable for flexible electronics. Their single‐resonator design with a fixed cavity length also limits long‐wave infrared (LWIR) emissivity (ɛ) regulation efficiency (Δɛ) and spectral coverage. Extending this to multi‐resonator configurations on 3D flexible fabric's nanofibers has the potential to enhance Δɛ and spectral coverage, which remains challenging. A temperature‐responsive metafabric featuring nanofibrous resonators is reported for the first time, achieving a Δɛ of up to 0.69, with ɛ of 0.85 at hot temperatures and 0.16 at cold temperatures, while regulating visible (VIS) and near‐IR (NIR) light from solar irradiation, thereby enabling self‐adaptive thermoregulation. The multi‐fibrous resonator system offers a 5.6‐fold increase in Δɛ and a 3.8‐fold broader spectral coverage compared to a single fibrous resonator. This passive VIS‐NIR‐LWIR self‐adaptive metafabric offers an eco‐friendly solution for electronics thermoregulation under fluctuating temperatures.