ADSORPTION OF COPOLYMERS OF POLY(ACRYLAMIDE) GRAFTED TO POLY(VINYL ALCOHOL) AND ITS EFFECT ON THE ELECTROKINETIC POTENTIAL OF SILICA

The adsorption of copolymers of poly(acrylamide) grafted to poly(vinyl alcohol) on a silica surface from aqueous solution has been investigated. Adsorption of these copolymers reduces the absolute values of the electrokinetic potential, but does not change the surface charge density of silica. The adsorption of the copolymers and its effect on the electrokinetic potential depend on the degree of grafting. Comparison of the ''electrokinetic'' polymer layer thicknesses with the molecular size in solution leads to the conclusion that considerable deformation of the intramolecular polymer complex occurs on adsorption. The mechanism of this phenomenon is discussed.