Spreading Dynamics and Predictive Modeling for Liquid Droplets Impacting Elastic Heterogeneous Surfaces

The impact behavior of droplets on heterogeneous hydrophilic-hydrophobic surfaces has significant research value for applications such as surface coating and inkjet printing. However, due to the nonuniform distribution of surface wettability, the mechanisms governing dynamic spreading during droplet impact remain unclear. Through systematic experiments, this study investigates the dynamic spreading behavior of droplets on flexible, heterogeneous surfaces with varying hydrophilic-hydrophobic properties under different Weber numbers, revealing how substrate flexibility modulates energy dissipation and contact line dynamics, thereby influencing the maximum spreading diameter. Building upon classical droplet spreading theory for rigid walls, a predictive model for the maximum spreading diameter of droplets on flexible, hydrophilic-hydrophobic heterogeneous surfaces is established. The model is optimized and validated using experimental data. This research provides theoretical support for the controlled deposition of droplets on heterogeneous, flexible surfaces. It offers an important reference for studying fluid-dynamic behavior on complex wettable surfaces.