Directional Motion of Water Droplet on Nanocone Surface Driven by Curvature Gradient: A Molecular Dynamics Simulation Study

This research work focuses on the wetting behavior and directional motion of water droplet on the nanocone surface through molecular dynamics simulation approach. A total of five nanocones having different apex angle were utilized to observe the wetting characteristics. In addition, water droplets of different sizes based on containing number of molecules were also considered in this study. The results show that the water droplet spontaneously travels from the tip of the nanocone toward its larger diameter direction in all cases. The average velocity of water droplet on the nanocone surface with smaller apex angle was found to be higher than that with larger apex angle. Moreover, it was found that the energy parameter of the nanocone surface and the size of water droplet have a significant effect on the wetting characteristics and velocity of droplet. Furthermore, three different equilibrium states of the water droplet on the nanocone surface were observed; unwet, partially wet, and fully wet. The velocity of the droplet was comparatively higher in the fully wet state as compared to the partially wet equilibrium state.