  Dynamic behavior of micro water droplet condensed on a lotus leaf with
two-tier roughness is studied. Under laboratory environment, the contact angle
of the micro droplet on single micro papilla increases smoothly from 80 deg to
160 deg during the growth of condensed water. The best-known "self-clean"
phenomenon, will be lost. A striking observation is the out-of-plane jumping
relay of condensed droplets triggered by falling droplets, as well as its
sustained speed obtained in continuous jumping relays, enhance the automatic
removal of dropwise condensation without the help from any external force. The
surface tension energy dissipation is the main reason controlling the critical
size of jumping droplet and its onset velocity of rebounding.
