Biomimetic Nanochannel Nanofibers with Enhanced Superhydrophilicity for Efficient Moisture-Wicking Fabrics.

Unidirectional moisture-wicking fabrics have garnered significant attention due to their ability to swiftly transport sweat away from the surface of the human skin, thereby enhancing the thermal and moisture comfort of athletes, boiler workers, and other individuals engaged in high-temperature occupations. However, existing nylon/polyester moisture-wicking fabrics lack rapid transport, causing discomfort. Therefore, inspired by bamboo fiber, multistage water-conducting fibrous membranes with superhydrophilic nanochannel and asymmetric wettability are prepared via multistep electrospinning and soaking treatment. Blend electrospun polyacrylonitrile (PAN)/polyvinyl butyral (PVB) nanofibrous membranes were soaked in ethanol to remove the PVB component, forming bamboo fiber-like PAN nanofibers with oriented superhydrophilic nanochannels. Based on the introduction of low surface energy fluorinated polyurethane (FPU), the hydrophobic polyurethane (PU)/FPU layer was further constructed and combined with the PAN-PVB layer via electrospinning, leading to the formation of an asymmetric wettability interface. The asymmetric wettability interface enabled water to rapidly transfer from the hydrophobic side to the hydrophilic side vertically, and the nanochannels in PAN nanofibers facilitated the quick diffusion and evaporation of liquid water horizontally. The resulting multistage water-conducting structure endowed the bilayer membranes with excellent accumulative one-way transport capacity (671%) and high overall moisture management capacity (0.80). Overall, the customized structure and water directional transport performance of the membranes promote the development of thermal-wet comfort fabrics and inspire functional nanofibrous materials.