Biomimetic Murray nanofiber membranes with pore/wetting double gradient for ultrafast directional water transport and evaporative textiles

Directional water transport (DWT) textiles, possessing moisture-wicking and evaporative fast-drying capabilities, help in creating a comfortable microenvironment for the human body. However, fabricating synthetic materials that follow Murray's law and replicate the pore gradient of vascular plants remains challenging, thereby impeding the achievement of a good combination of moisture conduction, fast drying, and osmosis resistance. In this study, DWT membranes comprising three layers of pore/wetting gradients were constructed using a straightforward electrospinning/netting technique. The inner and intermediate layers, comprising hydrophobic polyurethane (PU) and hydrophilic PU-hydrolyzed poly-acrylonitrile (PU-HPAN) nanofibers with average diameters of 1.83 lm and 255 nm, respectively, were prepared via electrospinning. Furthermore, the superhydrophilic outer layer (HPAM) comprised HPAN and a blend of acrylic acid/acrylamide with an average diameter of 76 nm. This layer was prepared via the electro-netting of dilute solution with high electrical conductivity, resulting in a spontaneous and continuous water transport, coupled with rapid drying. The DWT membranes exhibited an ultrahigh one-way transport capability (R) of 1270%, achieving an evaporation rate of 0.86 g h-1. Additionally, they demonstrated rapid drying within 16 min, effectively preventing reverse osmosis under pressure. Therefore, these membranes can be applied for moisture wicking, water extraction, and micro fluidic control. (c) 2023 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.