ADSORPTION LAYERS OF POLY(ETHYLENE OXIDE) ON QUARTZ STUDIED USING CAPILLARY ELECTROKINETICS

The adsorption of poly(ethylene oxide) (PEO) molecules decreases the e lectrokinetic potential of a quartz surface. The corresponding change in electrostatic forces may influence the interaction between colloida l particles in polymer solutions. The equilibrium between flowing PEO solution and adsorption layers in thin quartz capillaries is establish ed after 1-2 h. The kinetics may be controlled by the attachment and r econformation of polymer molecules in the adsorbed layers. The saturat ed adsorption layers of PEO are easily deformed under the action of th e shear stress of the flowing solution. The effect of shear stress req uires further investigation using joint measurements of the adsorption and the hydrodynamic and electrokinetic thicknesses of the adsorption layers. The thin quartz capillaries represent a simple model system w ith a well-characterized geometry and a molecularly smooth surface. Ca pillary electrokinetics may effectively be used for the investigation of electrosurface phenomena in polymer solutions.