Poly(ethylene oxide)-sodium dodecyl sulfate interactions studied using static and dynamic light scattering

Static and dynamic light scattering measurements have been made on poly(ethy1ene oxide) \n(PEO) in the presence of the ionic surfactant sodium dodecyl sulfate (SDS) in aqueous solution over a range \nof relative concentrations. The purpose was, in part, to demonstrate the polyelectrolyte effecte which arise \nin PEO on formation of the charged complex between the components in solution in which small SDS micelles \nare incorporated into the flexible PEO coil. The influence of the ionic strength of the medium was studied. \nStatic light scattering measurements show that the radius of gyration changes as a function of SDS concentration \nand the ionic strength of the medium. Diffusion coefficients from dynamic light scattering (DLS) reflect \nchanges in the pair interaction potential as the SDS and ionic strength are altered. Laplace inversion of the \nDLS time correlation function gives relaxation time distributions consisting of the PEO/SDS complex as the \nmain component and free SDS micelles as the minor component. Changes in peak areas are related to the \nincrease in the degree of binding between SDS and PEO as the relative concentrations change and also the \nincrease in SDS micellar size with increase in the ionic strength of the medium.