HYDRODYNAMIC THICKNESS AND DEFORMATIONAL PROPERTIES OF ADSORPTION LAYERS OF POLY(ETHYLENEOXIDES)

From the measurements of surface potentials of quartz capillaries befo re and after adsorption of poly(ethylene oxides) (PEO) of various mole cular mass, an assessment of the equilibrium hydrodynamic thickness de lta of the adsorption layers has been obtained. The results have been compared with those of independent measurements of delta. The flow of the polymer solution under increasing pressure drops at the ends of a capillary, which causes the corresponding shear stress (tau) on the su rface of adsorbed PEO layers, results in the deformation of the latter , which manifests itself in decreasing delta. The delta values decreas e by several times when the shear stress tau rises to 2x10(2) m(-2). S uch values of tau have been obtained using thin capillaries (r = 5 div ided by 6 mm) and by application oft he capillary electrokinetic metho d with pressure drops up to 5 divided by 6 MPa.