Molecular rolling friction: the cogwheel model
  With the help of a two-dimensional model we study rolling lubrication by circular (2D fullerenes) molecules for a wide range of parameters. The conditions under which microscopic rolling friction may be effective are identified and related to the relative ingraining between substrate and molecule, the latter behaving as a nanosized cogwheel. 
O. M. Braun and Erio Tosatti