Self-propelled film-boiling liquids
  We report that liquids perform self-propelled motion when they are placed in contact with hot surfaces with asymmetric (ratchet-like) topology. The pumping effect is observed when the liquid is in 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. 
H. Linke, B. J. Aleman, L. D. Melling, M. J. Taormina, M. J. Francis,   C.C. Dow-Hygelund, V. Narayanan, R. P. Taylor, and A...