Advanced Janus Membrane with Directional Sweat Transport and Integrated Passive Cooling for Personal Thermal and Moisture Management

Passive cooling holds tremendous potential in improving thermal comfort because of its zero energy consumption and cost-effectiveness. However, currently reported radiative cooling materials primarily focus on hydrophobic polymer films, inevitably leading to sweat accumulation and limited cooling efficiency in hot-humid environments. Herein, an advanced Janus membrane with excellent temperature–moisture management capabilities is developed, which combines radiative cooling and evaporative heat dissipation. Modification with Calcium sulfite (CaSO₃) nanoparticles not only enhances the optical properties (state-of-the-art solar reflectance of 96.6%, infrared emittance of 96.1%) but also improves the wettability of the polylactic acid fiber membrane. Especially 15% emittance improvement is achieved due to the strong infrared radiation ability of CaSO₃. The membranes with opposite wettability realize the directional sweat transport (high one-way transport index of 945%). Excellent radiative cooling capability is demonstrated with sub-ambient cooling of 5.8 °C in the dry state. The Janus membranes covering sweaty skin exhibit a 46% shorter drying time and a 2 °C lower average evaporation temperature compared to cotton fabric, indicating highly efficient thermal and moisture management. This work provides an efficient route to achieving smart textiles that enable the human body to adapt to complex environmental conditions.

Graphical Abstract