Vampire bat's tongue-inspired superhydrophilic flexible origami channel for directional and spontaneous liquid manipulation

Abstract

Achieving continuous, directional fluid manipulation without external energy input is promising in current systems. However, designing a spontaneous fluid manipulating system with simplified fabrication, deformation, and integration remains challenging. Inspired by a vampire bat's tongue, herein, a superhydrophilic flexible origami channel (SFOC) with parallel-arranged superhydrophilic V-grooves is proposed to improve liquid transport and holding capability against gravity. The SFOC with a 1 mm depth can reach a maximum transport speed of 65 mm s⁻¹ and a liquid holding ability of 70 μL cm⁻², which is about 4.6 times higher than that of a superhydrophilic sheet. The rigidity of the material enables continuous liquid transport up to 7 cm through assembly. Coupled with the material's flexibility, a complex topological SFOC is designed, further facilitating directional fluid transport. The topological SFOC is further applied in fog collection to expand its functionality. Compared with the flexible superhydrophilic sheet, harvested fog water can be directionally transported and collected. Furthermore, a branch-inspired all-in-one liquid collector is designed, which can achieve a gravity-independent fog collection process as well as directional fog water transport and collection process in one step. We believe this work simplifies the fabrication of fluid transfer platforms and introduces effective strategies for fluid manipulation through 3D deformation and assembly, enhancing their suitability for practical fluid manipulation applications.