Research on the dynamic characteristics of micro-scale droplet impact

Abstract

Micro-scale droplet impact behavior is widely observed and holds critical significance in various fields such as inkjet printing, anti-icing, and spray cooling. However, current research has primarily focused on millimeter-scale droplets, leading to a lack of understanding regarding the dynamics of micro-scale droplets. To address this gap, our research systematically analyzed the impact and rebound behaviors of droplets of various sizes on microstructur surfaces, revealing the significant influence of droplet size on dynamic characteristics. The results revealed that micro-scale droplets exhibit markedly distinct morphological evolution during spreading, contraction, and rebound compared to millimeter-scale droplets. As droplet size decreases, the minimum rebound velocity threshold significantly increases, contact time extends substantially, and viscous dissipation becomes the primary energy loss mechanism in micro-scale droplets, resulting in a dramatic decrease in the restitution coefficient. Based on energy balance analysis, we developed a theoretical model to characterize the restitution coefficient of micro-scale droplets, demonstrating strong concordance with the experimental results. This research provides novel insights into the dynamic behavior of micro-scale droplets and offers theoretical support for surface design in diverse applications such as biomedical printing, aircraft anti-icing, and electronic device cooling.