Polymer, particle, surfactant interactions

The effect of the surfactant sodium dodecyl sulphate (SDS) on the adsorption properties of the homopolymer poly(ethylene oxide) (PEO) at the solid-liquid interface has been studied using a variety of techniques: photon correlation spectroscopy (PCS), nuclear magnetic resonance (NMR) spectroscopy and small-angle neutron scattering (SANS). Physisorbed, grafted, and dendritic polymers have been studied. Across the range of systems studied, a remarkably consistent general picture has emerged. For the physisorbed system, the surfactant affected both the adsorption of the polymer and the extension of its adsorbed layer. For systems where the adsorbed amount was held at a constant value, the polymer structure was significantly perturbed by the addition of surfactant. It is proposed that the polymer layer structure is not governed by competitive adsorption for the interface, but by a competitive polymer-surfactant interaction. (C) 1999 Elsevier Science B.V. All rights reserved.