Durable asymmetric silk fabric with rapid heat conduction, spectral selectivity and sweat transfer capabilities for effective personal thermal-moisture management

Silk fabric (SF) is a high-end textile frequently utilized in summer apparel. However, its ultraviolet absorption reduces the solar energy reflection, and the inherent hydrophilicity impedes effective sweat evaporation, thereby significantly compromising thermal-moisture comfort. Herein, we fabricated a multifunctional Janus SF with rapid heat dissipation, unidirectional moisture conduction and radiative cooling capabilities through a feasible two-step process. Briefly, hydrophilic Al 2 O 3 nanoparticles were covalently anchored on the outer side (A-side) of Janus SF, whereas a hydrophobic boron nitride (BN) nanosheet-doped layer was fabricated on the inner side (B-side) via polycondensation reaction. The optimized Janus SF demonstrated exceptional solar reflectivity (93.62 %) and infrared emissivity (92.08 %), alongside enhanced thermal conductivities (1.45 W/K/m in-plane and 0.182 W/K/m through-plane). Additionally, the wettability gradient between the hydrophilic A-side and hydrophobic B-side provided a robust driving force for moisture transport, endowing Janus SF with a distinguished unidirectional transportation index of 809.43 % and a satisfactory water evaporation rate of 88.49 g/(m 2 ·h), thereby ensuring prolonged thermal-moisture comfort. Notably, this Janus fabric displayed remarkable outdoor practical cooling effect (∼5.6 °C) compared to bare skin, accompanying with good biocompatibility and outstanding wearability. Overall, such durable, scalable and multifunctional Janus SF provides innovative inspiration for designing next-generation passive cooling fabrics.