An Eco-Friendly Dual-Gradient Janus Fabric for Personal Thermal-Moisture Management

The increasing frequency of extreme weather events underscores the urgent need for personal thermal management. However, developing thermal management materials that effectively accommodate human perspiration remains a key challenge. In this study, we utilized polylactic acid (PLA), a green and biodegradable polymer, as the substrate to fabricate a high-performance asymmetric Janus radiative cooling fabric via a continuous spinning process. The Janus fabric (JF) features a hydrophilic top layer (JF-T) and a hydrophobic bottom layer (JF-A). This unique structure synergistically integrates radiative cooling, directional sweat wicking, and unidirectional heat conduction, achieving a solar reflectance of 91.02% and a mid-infrared (MIR) emissivity of 95.34%. Under direct sunlight, the JF achieves a maximum subambient cooling of 7.2 °C. Moreover, it demonstrates an impressive water evaporation rate of 651.88 g m^-2 h^-1, alongside excellent breathability and liquid diffusion properties, which translates to rapid sweat removal and a drier microclimate for enhanced wearer comfort during prolonged or high-intensity activities. This work presents a scalable strategy for developing eco-friendly cooling textiles aimed at enhancing outdoor thermal comfort, showing significant promise for integration into next-generation wearable technologies.