Nano-droplet jumping due to surface wettability variation: molecular modeling approach

The effect of substrate hydrophobicity on the dynamics of water nano-droplets is computationally studied using the molecular dynamics method. It is observed that the droplet moves upward by increasing the substrate hydrophobicity and then falls down onto the substrate, and during this process, the droplet-substrate interfacial area effectively declines. Moreover, the results indicate that above a critical substrate hydrophobicity, which depends on the droplet radius, the droplet completely detaches from the substrate. The droplet behavior is described at the molecular level using van der Waals attractions for the liquid-solid interface.