Fast & Scalded: Capillary Leidenfrost Droplets in micro-Ratches

In this Fluid Dynamics Videos submitted to the 31st Gallery of Fluid Motion, (find a different version here http://youtu.be/CS0c05WQ_js) we illustrate the special dynamics of capillary self-propelled Leidenfrost droplets in micrometric Ratchets. In order to be able to propel water droplets of sizes of the order of 1 mm, micro-ratchets were produced by direct material removal using a picosecond pulsed laser source. Surface micro-patterning with picosecond laser pulses allows creating a well controlled topography on a variety of substrates, with a resolution typically in the micron range. More information can be found in references.