Study on droplet wettability of low surface tension working medium based on special-shaped microstructure surface

Abstract

The wetting properties of droplets on microstructure surfaces directly determine the hydrophobic properties of the surface, and the size effect is an important part of the study of droplet wettability on microstructure surfaces. Taking reentrant special-shaped microstructure and doubly-reentrant special-shaped microstructure as the research objects, the influences of many geometric parameters of microstructure on the wetting characteristics of droplet with low surface tension were obtained by numerical simulation and theoretical analysis, and the concept of critical intrinsic contact angle was proposed. It is found that the two kinds of special-shaped microstructures can suspend the droplet with low surface tension, and the droplet finally presents a large apparent contact angle. However, there are three kinds of wetting transition (Cassie state →Wenzel state transition) on the surface of the doubly-reentrant special-shaped microstructure, so the wetting regulation mechanism of the surface with the same geometric parameters is different from that of the reentrant special-shaped microstructure. In addition, by analyzing the energy barrier at the pinning point, it is further proved that the doubly-reentrant special-shaped microstructure has better performance of inhibiting the wetting transition of droplet.