Electroacoustic study of adsorption of PEO on sunflower oil-in-water emulsion drops

The electroacoustic signals of sunflower oil-in-water emulsion droplets stabilized by sodium dodecyl sulfate (SDS) were affected by the adsorption of poly(ethylene oxide) (PEO). Large changes in the dynamic mobility of the coated oil droplets measured with an AcoustoSizer-II apparatus were observed. The results are interpreted with the aid of O'Brien's "gel layer" model, which gives an estimate of the elasticity and the approximate thicknesses of a dense inner and an extended outer adsorbed polymer layer. The thicknesses of both the inner and the outer layer increased smoothly with increasing concentration of polymer and the rate of increase increased with molar mass of the polymer with average molecular weights of 1500, 10 000, and 35 000.