Self-propelled Leidenfrost droplets

Phys Rev Lett. 2006 Apr 21;96(15):154502. doi: 10.1103/PhysRevLett.96.154502. Epub 2006 Apr 19.


We report that liquids perform self-propelled motion when they are placed in contact with hot surfaces with asymmetric (ratchetlike) topology. The pumping effect is observed when the liquid is in the Leidenfrost regime (the film-boiling regime), for many liquids and over a wide temperature range. We propose that liquid motion is driven by a viscous force exerted by vapor flow between the solid and the liquid.