固体表面液滴定向运动行为研究进展

The directional motion of droplets on solid surfaces is of great research value and has been widely used in water collection, oil-water separation, microfluidics, etc., which has become a research hotspot in the field of surface interface. At the same time, the study of droplet orientation motion behavior is of great significance for understanding the mechanism of action between liquid and solid surfaces. However, the current research on the directional movement of droplets mainly focuses on macroscopic scale observation and analysis, lacks in-depth exploration of the basic principles and lacks understanding of the basic conditions for achieving droplet directional motion. At the same time, the current artificial biomimetic materials are complicated and costly, and their relatively short moving distance and relatively small moving speed limit their application range. In addition, although the majority of scholars have made great achievements in the research of droplet directional motion behavior, such as micro-mixers, fluid diodes, etc., these studies are only limited to the "laboratory" stage, applying it widely to daily life needs further research. Fortunately, the current scholars have started from the basic principle of droplet wetting and found that the surface of natural materials such as cactus, Nepenthes alata, Sarracenia, spider silk and butterfly, etc. can realize the directional movement of droplets. And the directional movement speed of droplets on the surface of Sarracenia trichome is up to (1 1738±715) μm•s^-1. On this basis, the majority of scholars have made further biomimetic research on cactus spine, Nepenthes alata peristome, Sarracenia trichome, spider silk, etc. by electrospinning, electrochemical etching, photolithography, dip-coating, etc., and the biomimetic spider silk achieves reversible movement of the droplets and efficient water collection. In addition, inspired by the directional movement of droplets on the surface of natural materials, some scholars have developed topological fluid diodes that realize rapid, long-distance and direction-controllable movement of droplets. The simple arrow-shaped microstructures provide a possibility for practical applications. This paper comprehensively reviews the recent research progress of domestic and foreign scholars on the surface directional movement beha-vior of natural materials such as cactus, Nepenthes alata, Sarracenia, spider silk and butterfly. The basic principle of directional movement of so-lid surface droplets is analyzed from the angle of force, and a typical example of bionic self-orienting surface at home and abroad is demonstrated. Finally, some suggestions for future research work are presented.