Analysis of Droplet Dynamics on Superhydrophobic Functional Surfaces

This paper investigates the influence of key factors on droplet dynamics on superhydrophobic surfaces, providing theoretical guidance for their design and application. Using the fluid flow module of COMSOL Multiphysics, a two-dimensional simulation of droplet collision and coalescence–rebound was carried out on surfaces with various microstructures. The simulation results agreed well with experimental data, confirming the accuracy of the model. The study shows that as microstructural spacing increases, the solid–liquid contact area decreases, wall viscous dissipation reduces, and droplets retract and rebound more rapidly. The surface morphology, the contact angle, the droplet radius, and the initial kinetic energy strongly affect the dynamic behavior. During coalescence and bouncing, both the droplet radius and the microstructural morphology are decisive, while the higher initial velocity enhances rebound. Conversely, a smaller radii ratio between two droplets hinders detachment and may cause rebound deviation. Overall, six dominant factors were identified, namely, three related to the surface structure and three to the droplet properties. These findings establish a theoretical foundation for optimizing the design and functional application to superhydrophobic surfaces.