Effect of polymer adsorption on the properties of the electrical double layer

Abstract

The adsorption isotherm of a neutral polymer, poly(vinyl alcohol), on the hydrated aluminium oxide gibbsite has been measured. Much higher adsorption densities were obtained than have been observed with other colloidal systems. Surface charge measurements indicate that no change either in the isoelectric point or the capacitance of the electrical double layer occurs as a result of the adsorption of the polymer. A large reduction however is observed in the value of the electrophoretic mobility of the gibbsite in the presence of poly(vinyl alcohol). This is attributed to a displacement of the plane of shear by the adsorbed polymer.