An Al2O3-cellulose acetate-coated textile for human body cooling

The development of a textile that cools skin both in sunshine and in room can not only protect the human body from a severely hot working environment but also save energy by lowering air conditioner load. Herein, we have developed a concept that combines solar energy reflection and “passive radiative cooling” for strengthening both solar energy blocking and heat dissipation through long-wave infrared (LWIR) radiation at wavelengths of 8–13 μm. The current technique is achieved by coating a textile with an Al2O3 dispersed-cellulose acetate. Cellulose acetate possesses high emissivity in the LWIR region, which can promote effective LWIR radiation (2.5–25 μm). Al2O3 has a high thermal conductivity (30–40 W m−1 K−1) and can enhance solar energy reflectivity. By coating Al2O3-cellulose acetate, solar energy reflectivity of the textile significantly increases from 62.6% to 80.1% (0.3–2.6 μm). A cooling performance experiment reveals that this modified textile can reduce the temperature of simulated skin by 2.3–8 °C compared to that of an unmodified reference. Furthermore, in a real-life cooling performance experiment, a modified T-shirt can avoid the overheating of actual human skin by 0.6–1.0 °C, corresponding to a temperature decrease by 1.9–3.3 °C for the internal surface of the textile. This work provides a method for the design and synthesis of radiative cooling textiles for personal thermal management.