Rapid Drop Dynamics During Superhydrophobic Condensation

Rapid drop motion is observed on superhydrophobic surfaces during condensation; condensate drops with diameter of order 10~$\mu $m can move at above 100G and 0.1 m/s. When water vapor condenses on a horizontal superhydrophobic surface, condensate drops move in a seemingly random direction. The observed motion is attributed to the energy released through coalescence of neighboring condensate drops. A scaling analysis captured the initial acceleration and terminal velocity. Our work is a step forward in understanding the dynamics of superhydrophobic condensation occurring in both natural water-repellant plants and engineered dropwise condensers.