Tunable Radiative Cooling by Mechanochromic Electrospun Micro‐Nanofiber Matrix

Abstract Radiative thermoregulation has been regarded as an energy‐efficient method for thermal management. In this study, the development of a mechanoresponsive polydimethylsiloxane (PDMS) micro‐nanofiber matrix capable of both sub‐ambient radiative cooling and solar heating is presented, achieved through a core‐shell electrospinning technique. The electrospun PDMS micro‐nanofibers, with diameters comparable to the solar wavelengths, exhibit excellent solar reflectivity (≈93%) while preserving its pristine high infrared (IR) emissivity. As a result, the electrospun PDMS radiative cooler (EPRC) successfully demonstrated sub‐ambient radiative cooling performance (≈3.8°C) during the daytime. Furthermore, the exceptional resilient property of PDMS facilitated the reversible alteration of the structural morphology created by the fiber‐based matrix under mechanical force, resulting in the modulation of solar reflectivity (≈80%). The precise modulation of solar reflectivity enabled reversibly switchable multi‐step radiative thermoregulation, offering enhanced flexibility in addressing varying thermal environments even in maintaining the desired temperature. The findings of this work offer a promising approach toward dynamic radiative thermoregulation, which holds significant potential for addressing global climate change concerns and energy shortage.