Theory of the observed ultralow friction between sliding polyelectrolyte brushes.

It is shown using a method based on a modified version of the mean field theory of Miklavic and Marcelja [J. Phys. Chem. 92, 6718 (1988)] that it should be possible for osmotic pressure due to the counterions associated with the two polyelectrolyte polymer brush coated surfaces to support a reasonable load (i.e., about 10(6) Pa) with the brushes held sufficiently far apart to prevent entanglement of polymers belonging to the two brushes, thus avoiding what is believed to be the dominant mechanisms for static and dry friction.