CAPILLARY ELECTROKINETIC STUDY OF COMPETITIVE ADSORPTION OF POLYACRYLAMIDE AND ETHOXYLATED ALKYLPHENOL FROM AQUEOUS-SOLUTIONS ON THE SURFACE OF QUARTZ GLASS

A capillary electrokinetic study of competitive adsorption of a nonionic polymer, polyacrylamide (PAA), and a nonionic surfactant, ethoxylated alkylphenol R9phiE10, from solutions prepared against 10(04) M KCl was conducted. It was shown that the zeta potential in solutions of SF differs little from the zeta in 10(-4) M KCl solution, while zeta decreases to almost zero in PAA solutions. This is due to the formation of relatively extensive adsorption layers of PAA, attaining 96 nm on the surface Of SiO2. The detected increase in \zeta\ in dilute solutions of PAA containing small amounts of SF (10(-5)-10(-4) M) is due to a decrease in adsorption of PAA and thinning of the adsorption layer, confirmed by direct measurements of adsorption of PAA from mixed solutions on quartz powder. In turn, adsorption of SF remains constant and is not a function of the presence of macromolecules in the solution. The results of the electrokinetic and adsorption studies were compared with the data on the solubilizing capacity of SF in PAA solutions. It was shown that despite the fact that association of uncharged macromolecules with NSF molecules takes place in mixed solutions, the individual components primarily participate in adsorption on a solid surface.