Tunable Radiative Cooling by Mechanochromic Electrospun Micro-Nanofiber Matrix

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 (approximate to 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 (approximate to 3.8 degrees 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 (approximate to 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. A novel mechanoresponsive electrospun PDMS micro-nanofiber matrix is developed for an energy-efficient tunable radiative cooling technology. Utilizing continuously variable solar reflectivity of the electrospun PDMS micro-nanofiber matrix, it demonstrates dynamic radiative thermoregulation ranging from sub-ambient to above-ambient temperature through pressure manipulation. Thereby, the matrix showcases its capacity to actively adapt to global energy shortages and rapidly changing abnormal climates.image