A water film motor
  We report on electrically-induced rotations in water films, which can function at many length scales. The device consists of a two-dimensional cell used for electrolysis of water films, as simple as an insulator frame with two electrodes on the sides, to which an external in-plane electric field perpendicular to the mean electrolysis current density is applied. If either the external field or the electrolysis current exceeds some threshold (while the other one is not zero), the liquid film begins to rotate. 
R. Shirsavar, A. Amjadi, N. Hamedani Radja, M. D. Niry, M. Reza Rahimi   Tabar, M.R. Ejtehadi