Rendering passive radiative cooling capability to cotton textile by an alginate/CaCO3 coating via synergistic light manipulation and high water permeation

Personal thermal management textiles that put focus on cooling human body in hot environment attracts intense research interests since the urgent requirement for adjusting human activity to save energy even when we face extreme weather more frequently. Textiles produced from petrol-based fibers have shown their effective passive cooling effects. However, regeneratable passive cooling textiles are still lacking. In this study, we report a cotton-based effective passive cooling textile by interfacial engineering by alginate modification and in-situ generated CaCO3 particles. The Alg/CaCO3-cotton fabrics not only effectively cool the underlining surface via high reflectivity over solar spectra (∼90%) and high mid-infrared emissivity (0.97) in the atmospheric window, but also present enhanced water evaporation and water vapor permeation capabilities (36.51% higher water vapor transmission rate than pristine cotton fabric). The textile avoids overheating by 5.4 °C under direct solar irradiation, comparable to the performance of the reported petrol-based textile. The Alg/CaCO3-cotton also presents high washing stability, UV protection properties, faster drying and fire resistance properties. The surface engineering process is compatible with large-scale production. This work provides enlightening insights to regeneratable and wearable passive cooling materials and sheds light on the working mechanism of personal thermal management materials.