Characterization of polymers in the adsorbed state by double layer measurements. The silver iodide + poly(vinyl alcohol) system

Abstract

Double layer and electrophoresis studies have been used to determine the mode of adsorption of poly(vinyl alcohol) on silver iodide. The properties of the Stern-layer are modified by polymer segments, adsorbing in trains. Adsorbed polymer trains and low molecular weight organic adsorbates behave very similarly in this layer. This similarity has been used to develop a theorem to obtain the degree of occupancy of train segments in the Stern-layer. The obtained result is confirmed by electrophoresis studies. A measure for the effective layer thickness can be obtained from the slope of the electrophoretic mobility against pAg curve around the isoelectric point. The main conclusion is that the fraction adsorbed in trains and the effective layer thickness are to a first approximation a function of the adsorbed amount only and independent of acetate content and molecular weight of the polymer.