Bioinspired Unidirectional Liquid Spreading Channel–Principle, Design, and Manufacture

Liquid unidirectional spreading without energy input has attracted worldwide attentions owing to its potential applications in various fields. The liquid transfer between the adjacent microcavities on the peristome of Nepenthes alata provides great inspiration in that the concave curvature edge structure has the possibility to induce liquid directional spreading. Herein, the effect of concave curvature edge on liquid spreading is found to be different from that of the solid edge described by the Gibbs inequality condition. In this condition, there exist two liquid transfer states, namely conduction and resistance. Taking the advantages of the concave curvature edge, a new unidirectional liquid spreading channel is designed and fabricated by the traditional machining method, and its liquid directional spreading function is validated. This article provides a theoretical and technical support for the design and fabrication of liquid unidirectional spreading channel without an external energy input.