Lubrication forces between surfaces bearing polymer brushes

We have studied both the equilibrium and the hydrodynamic lubrication forces that act in the normal direction between mica surfaces in toluene when bearing polystyrene chains anchored to each surface by a zwitterionic group at one end. The quasistatic force-distance profiles reveal the long-ranged repulsion characteristic of steric interactions between the extended brush-like layers in the good solvent and provide a measure of the brush thickness L in close agreement with earlier studies of such brushes