Bilayer Nanofibrous Membrane Integrating Radiative Cooling and Unidirectional Moisture Transport for Personal Thermo-Hygroscopic Management

To address the inadequacies of conventional textiles in terms of heat dissipation and moisture management in hot environments, a bilayer nanofibrous membrane was fabricated by using layer-by-layer electrospinning. This membrane integrates radiative cooling, enhanced thermal conduction, and unidirectional moisture transport. The outer layer, composed of hydrophilic cellulose acetate/polyethylene glycol (CA/PEG) nanofibers, exhibits a solar reflectance of 93.9% and an atmospheric window emissivity of 95.8%. Under outdoor conditions, this design enables a maximum reduction of up to 12.1 °C in the skin temperature beneath the membrane compared with cotton. The inner layer, composed of polylactic acid (PLA) nanofibers doped with hexagonal boron nitride (hBN), exhibits enhanced in-plane thermal conductivity combined with excellent hydrophobicity. The asymmetric wettability of the bilayer structure allows water droplets to be spontaneously transported from the skin-facing inner layer to the outer layer, effectively preventing sweat accumulation. Moreover, the porous architecture of the bilayer membrane ensures an air permeability comparable to that of conventional woven fabrics, thereby maintaining a high level of wearing comfort. Overall, this bilayer nanofibrous membrane represents a promising material for personal thermo-hygroscopic management in hot environments, owing to its integrated key thermo-hygroscopic capabilities and fabric-matching breathability.