Double-side super-hydrophilic/superspreading fabric for ultrafast asymmetric sweat transport and in-situ power generation

Asymmetric (viz. Janus or one-way transport) fabrics that can promote directional sweat transport from the next-to-the-skin surface to the outer surface by the hydrophobic-hydrophilic difference across the fabric thickness have been developed. However, the hydrophobic next-to-the-skin surface inevitably increases the inherent resistance to sweat transportation into the fabric, fundamentally hampering its moisture management property. In this work, by selectively coating a poly-pyrrole (ppy) film with Turing patterns on one side of the fabric to achieve superspreading property, we demonstrated an all-hydrophilic asymmetric fabric with outstanding one-way liquid sweat transport property. Benefiting from the low resistance of sweat absorption, the all-hydrophilic fabric exhibited a dramatically increased directional sweat transport rate of 13.6 mm/s, which is 5.9 times that of the untreated fabric, and significantly enhanced sweat evaporation rate (1.56 times of the untreated fabric) and cooling performance. Furthermore, the conductive ppy-fabric, during the process of ultra-fast sweat transport, generated a potential of 150 mV over an area of 2×2 cm² or scalable electrical energy output of 2.5 mW/m² under continuous sweat transportation. The finding in this work not only provided new insight into the design and development of asymmetric fabric for ultrafast sweat transport but also proposed a novel method for the in-situ energy harvesting during the sweat transportation process, which has potential applications in self-powered smart wearables and functional clothing.