Interactions between solid surfaces with adsorbed polyelectrolytes of opposite charge

Adsorption of polyelectrolytes to surfaces of opposite charge typically leads to charge neutralization and subsequent charge reversal. As can be shown by direct force measurements and stability studies, the interaction forces are dominated by repulsive forces originating from diffuse layer overlap and attractive van der Waals forces, in line with the classical theory of Derjaguin, Landau, Verwey, and Overbeek (DLVO). Recently, the existence of an additional attractive non-DLVO force was demonstrated, and its likely origin is the attraction between patch-charge heterogeneities. With novel single molecule pulling experiments with the atomic force microscope (AFM) polymer bridging forces could be shown to represent the most important contribution to the adhesion of surfaces coated by polyelectrolytes. (C) 2008 Elsevier Ltd. All rights reserved.