Molecular dynamics study of nanodroplet impact on superhydrophobic surfaces with varying inclination angles

The dynamic behavior of nanodroplets impacting solid surfaces has significant applications in fields such as anti-icing, self-cleaning, and nanotechnology. However, research on nanodroplet impacts on inclined superhydrophobic surfaces remains limited. In this study, molecular dynamics simulations are employed to systematically investigate the impact of nanodroplets on superhydrophobic surfaces with varying inclination angles. The study reveals the underlying mechanisms of droplet rebound modes, contact time, and sliding distance. The results demonstrate that droplet rebound behavior can be categorized into three modes: regular rebound, cavity rebound, and splashing rebound. The occurrence of these modes is governed by both the Weber number and the surface inclination angle. An analysis of contact time shows a three-phase variation: contact time decreases rapidly at low speeds, remains relatively stable at moderate speeds, and decreases significantly at high speeds. Notably, in the moderate-speed range, the formation of cavity rebound increases contact time, a phenomenon not commonly observed in previous studies on flat surfaces. Additionally, this study derives a theoretical formula for droplet sliding distance based on the Lennard-Jones potential and verifies it through simulations, demonstrating the competition between inertial forces and intermolecular interactions during sliding. The research not only presents a phase diagram of nanodroplet impact outcomes but also contributes novel theoretical insights into contact time and sliding behavior, providing a solid theoretical foundation for optimizing nanodroplet behavior in industrial applications.