Dynamic spreading characteristics of droplet on the hydrophobic surface with microstructures

Abstract

The behaviors of droplet impact on the two different microstructures (regular micro-grooved structure and irregular microstructure) exhibiting hydrophobic features are investigated experimentally in this study. Images captured by the high-speed cameras are used to examine the differences between regular and irregular microstructures on the droplet impact process. Dimensionless parameters including dimensionless spreading factor, height and time are introduced to quantitatively analyze the spreading process. The results show that two microstructure accelerate the droplet to reach the maximum dimensionless spreading factor and height, compared with flat surface. It should be also noticed that the droplet breaks up while bouncing on the irregular microstructure surface, which is because that the sum of kinetic and surface energy is slightly higher than the initial total energy during receding process. This study further shows that the beating phenomenon of the dimensionless height of the droplet impact is developed on the regular micro-grooved structure surface.