Self-Removal of Multiple and Multisize Coalescing Nanodroplets on Nanostructured Surfaces C

Coalescence-induced jumping on superhydrophobic surfaces has attracted extensive interest. It has recently been discovered that spontaneous removal is also possible for the nanodroplets. However, current studies focus on an ideal coalescence of two equally sized nanodroplets; the dynamics of nanodroplets and the mechanism of coalescence are not well understood when considering other practical factors. This work numerically investigated the practical coalescence processes of nanodroplets using molecular dynamics simulation, and systematically discussed the effects of nanodroplet number, initial size, and initial size ratio by analyzing the variation of jumping velocity and energy conversion efficiency. On the basis of all calculated results, we provided forecasts for jumping velocity and energy conversion efficiency of two coalescing nanodroplets with different sizes; the results show that both the jumping velocity and the energy conversion efficiency decrease roughly with increasing nanodroplet size and decreasing size ratio. The simulation results in this study demonstrate the possibility of coalescence-induced jumping of multiple nanodroplets with different sizes, and are very useful for predicting jumping velocities for nanodroplet coalescence events.