DYNAMIC LIGHT-SCATTERING AND SMALL-ANGLE NEUTRON-SCATTERING STUDIES ON THE POLY(ETHYLENE OXIDE) SODIUM DODECYL SULFATE/POLYSTYRENE LATEX SYSTEM/

Dynamic light scattering and small-angle neutron scattering measuremen ts have been performed on aqueous polystyrene latex dispersions with p hysisorbed polymer, poly(ethylene oxide), in the presence of the surfa ctant sodium dodecyl sulfate (SDS). Dynamic Light scattering measureme nts suggested that the polymer layer is partially desorbed at surfacta nt concentrations close to the critical micelle concentration. At surf actant concentrations above the normal critical micelle concentration, the hydrodynamic thickness increased close to the value in the absenc e of surfactant. Small-angle neutron scattering measurements suggested that as the normal critical micelle concentration of the surfactant w as approached, very thin layers were formed. It was possible to obtain the volume fraction profiles of the adsorbed polymer layer, along wit h information on the structure of the surfactant micelles. Two types o f SDS structures were observed, one corresponding to SDS existing boun d to bulk polymer and the other to SDS bound to adsorbed polymer.