Progress in Metafibers for Sustainable Radiative Cooling and Prospects of Achieving Thermally Drawn Metafibers

The growing awareness of the energy crisis and global warming has inspired researchers to pursue alternative cooling strategies. Radiative cooling is an environmentally friendly approach that dissipates excessive heat through the atmospheric long-wave infrared transmission window (8-13 mu m) to the cold universe. Metamaterials with unique photonic structures are applicable to radiative cooling and have been extensively studied. Incorporating meta-elements to the fiber level of the fabric to construct metafibers is expected to achieve personal thermal management through radiative cooling. Compared with the conventional fiber manufacturing methods, the thermal drawing technique can mass-produce multimaterial and multifunctional fibers with well-defined structures. These in-fiber micro- and nanostructures of light wavelength scale possess great potentials in radiative cooling applications, providing bright prospects for a new generation of metafiber-based smart fabrics. Herein, the fundamental principles of radiative cooling and the metamaterials being used for radiative cooling are summarized. The textiles used for personal cooling and their preparation methods are also introduced. Finally, the article focuses on the preparation of micro- and nanostructures by the thermal drawing technique, which provides a potential solution for the large-scale manufacture of metafibers for sustainable radiative cooling.