  Leidenfrost ratchets are structures with the ability of transporting liquid
droplets when heated over the critical Leidenfrost temperature. Once this
temperature is reached, the droplet levitates over the surface and moves in the
direction marked by the slope of the ratchet at terminal velocities around 10
cm/s. Here we provide new experiments with micron-sized ratchets, which have
been produced with picosecond pulse laser ablation. In the following work, we
use a simple method to measure the thrust driving droplets of capillary size
over the micro-ratchets. The mechanism responsible for the force acting on the
drop on superheated ratchets has been recently under debate. We extend the
recently proposed 'viscous mechanism' proposed by Dupeaux et al. [Europhys.
Lett., 96, 58001 (2011)] to capillary droplets and find good agreement with our
measurements.
