Experimental study on the influence of surface properties on droplet collision dynamics, from adhesion to rebound to breakup

Liquid droplet impact on dry surfaces often results in bouncing or breakup beyond a certain threshold. Surface contact angles, especially dynamic ones present during impact, significantly affect this process. Our experimental study underscores that advancing and receding contact angles influence droplet behaviors like rebounding and different types of breakup. This discovery provides new insights and criteria for understanding liquid droplet impact on surfaces. Special characteristics were found in the breakup on microstructured surfaces: the size of fractured droplets notably decreases, and the spreading–breakup occurs more easily and earlier. Additionally, microstructured surfaces reduce contact time to some extent. Furthermore, the uniqueness of oblique impacts is mainly reflected in how they lower the threshold of the receding contact angle for rebound. Studying the correlations and differences in droplet rebound and breakup related to these surface characteristics will contribute to improving research on liquid–solid interactions and the design of hydrophobic surfaces, including microstructured surfaces.