Scalable nanofibrous silk fibroin textile with excellent Mie scattering and high sweat evaporation ability for highly efficient passive personal thermal management

Passive personal thermal management based on radiative cooling textiles is emerging as a facile, cost-effective, and energy-efficient way for outdoor human body thermal comfort. Existing passive radiative cooling textiles are mainly built from synthetic polymers that are usually nonrenewable and non-degradable, and lack sweat management function. Herein, we report the fabrication of a biopolymer-based, nanofibrous textile that integrates passive radiative cooling and sweat transportation functions via a scalable electrospinning technique. The optimized control over the nanofibers’ diameter enables the 200 µm thick film with high reflectance in both the ultraviolet (UV) range (92%) and the entire solar spectrum (95%), and the abundant chemical bonds of silk fibroin allow a high emissivity of 95% in the atmospheric window. Consequently, the nanostructured textile can achieve a temperature of ∼3.8 °C below the ambient temperature during the daytime and ∼6.4 °C at night. More importantly, the use of hygroscopic silk fibroin offers additional functions of sweat absorption and evaporation. Outdoor sweat evaporation experiment demonstrates a temperature reduction of ∼5.5 °C for nanofibrous silk fibroin textile, compared with the traditional nonhygroscopic textile. Owing to its excellent combination of biodegradability, superior cooling ability, and high sweat transportation capacity, the scalable silk nanofabric would be an effective textile for passive personal thermal management.