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 nonion ic polymer, polyacrylamide (PAA), and a nonionic surfactant, ethoxylat ed 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 dec reases to almost zero in PAA solutions. This is due to the formation o f relatively extensive adsorption layers of PAA, attaining 96 nm on th e 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 d ecrease in adsorption of PAA and thinning of the adsorption layer, con firmed by direct measurements of adsorption of PAA from mixed solution s 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 wit h the data on the solubilizing capacity of SF in PAA solutions. It was shown that despite the fact that association of uncharged macromolecu les with NSF molecules takes place in mixed solutions, the individual components primarily participate in adsorption on a solid surface.