Polymer/Surfactant Interaction: Interfacial Aspects

Surface methods—especially surface tension measurements—have long been used in the study of interaction between water soluble polymers and surfactants. Many factors control “reactivity” in such systems. For example, hydrophobicity (and surface activity) of the polymer can be a dominant factor in the case of uncharged polymer/ionic surfactant pairs, while oppositeness of charge can be dominant in polyelectrolyte/ionic surfactant systems. In the latter case, “ideal” surface behavior in the Gibbsian adsorption sense is often observed. Other “surface” methods used, and briefly alluded to, include neutron reflection, surface rheology, radio tagging, ellipsometry, X-ray reflectivity, and the study of foams. Interaction at the solid/water interface, traditionally studied in mineral dressing research, is receiving increasing attention. References to the use of 20 different instrumental methods are given, together with a brief discussion of the use of three of them, namely electron spin resonance, photon correlation spectroscopy, and atomic force microscopy.