Ultrafast Self-propelling directionally water transporting wood via cell wall reshaping for water manipulation

Abstract

Water-transport based on biomimetic self-propelled directional water transport materials have attracted wide attention but are limited by low transport speed, costly and complicated preparation, and scaling difficulty. By retaining native cellulose microfibril structure within wood cell walls and their controlled shrinkage, we constructed a self-propelling directionally water transporting wood (SDTW) by reshaping the cell wall to generate robust capillary forces due to aligned longitudinal hierarchical wood cell structures. Hierarchical structures containing directional parallel macro- and micro-sized ridge-groove structures and creating nano-voids are fabricated. They are further intactly fixed after reaction with maleic anhydride to improve the dimensional stability and environmental durability without changing the hydrophilicity on surface. Resulting SDTW exhibited an ultrafast water transport speed of 200.4 mm/s (∼260 % of Nepenthes alata showing a fast speed of 78 mm/s as a native structure) and water absorbing rate of 1.15 × 105 L/m2/h (over 4200-fold higher than that of natural wood). With these ultrafast water transport characters, SDTW was used as water manipulating systems for fast bottom to up transportation of liquid water at a rate of 193.5 mm/s, and as high fog harvesting system with an efficiency of 10.6 g/cm2/h. With its facility, durability, scalability, and sustainability, the SDTW demonstrates a new class of sustainable wood-based materials for practical water manipulation applications.