Tailored Fabrics with Biomimetic Janus Spectral Responsiveness for All‐Weather Switchable Thermoregulation

Abstract In the face of global climate change, adapting to intensive temperature variation and maintaining stable body temperature in outdoor settings are crucial for keeping personal health and boosting labor productivity. Developing zero‐energy fabrics with switchable thermoregulation provides a feasible strategy for responding to this climate circumstance. However, integrating switchable thermoregulation into fabrics without compromising their structural integrity, comfortability, and fabrication scalability remains challenging. Here, inspired by the Bokermannohyla alvarengai, which adapts its skin color in Janus mode to different sunlight and temperature conditions by varying its pigment cells, the fabrics with Janus spectral responsiveness are designed. The radiative cooling micro‐fibers and photothermal micro‐fibers are assembled into tailored textures, constructing the single‐layer fabrics coupled with distinct thermoregulation functions on each side. The resulting Janus spectral responsiveness fabrics present a solar reflectivity of 83.9% in cooling mode and a solar absorptivity of 84.3% in heating mode, while the robust interlaced coil configuration of the fabrics not only maintains the rich porous structures but also enhances the structural integrity of the fabrics. Advancing single‐layer, dual‐mode fabrics may provide a promising pathway for all‐weather switchable personal thermoregulation, potentially optimizing the market for personal thermal management.