SURFACE FORCE STUDIES OF POLYMER-SURFACTANT COMPLEXES AT THE SOLID-LIQUID INTERFACE: RELATION TO STRUCTURE OF BULK COMPLEXES

This contribution focuses on interactions between polymers and surfactants at solid-liquid interfaces. This is a rather complex issue since one has to consider interactions between 4 components (polymer, surfactant, surface and solvent). The situation in bulk solution is somewhat easier to understand since one in this case only has to consider three components. A further complication is the very long equilibration times involved, particularly at interfaces. In fact, in many cases true equilibrium cannot be established within experimentally accessible time scales. This means that the end result, e.g. the structure of a surface coating, will depend on the history, e.g. on the order in which the components have been added. The paper will focus on two topics. We will first consider polyelectrolytes and oppositely charged surfactants in aqueous solutions. Here we will consider the effect of polyelectrolyte charge density, surfactant concentration and the order of adding the components. Next we will move on to systems consisting of uncharged polymers and phospholipids in non-polar media. In the latter case the water content in the solvent is seen to have important effects on the adsorbed layer structure.