COMPLEXATION OF IONOMERS AND SURFACTANT MOLECULES OF THE SAME CHARGE IN A NONPOLAR SOLVENT

Complexation between sulfonated polystyrene ionomers and bis(2-ethylhe xyl) sulfosuccinate sodium salt (aerosol OT, AOT) surfactant molecules in m-xylene was studied by ultracentrifugation, vapor pressure osmome try, viscometry, and dynamic light scattering. When the dilute ionomer solution is mixed with the AOT solution, complexation takes place for both the slightly aggregated state of AOT and reversed micelles of AO T containing water. In the presence of excess AOT molecules, some of t he AOT are free from the ionomers, and there are well-defined limiting compositions for complexes of the ionomer and AOT and for those of th e ionomer and AOT micelles. The limiting composition depends on the sp ecies of the salt or acid group of the ionomer and on the state of AOT before mixing. The composition was estimated to be 0.21-0.66 reversed AOT micelles per salt/acid group for the ionomer-AOT micelle complexe s and 14-23 AOT molecules per salt/acid group for the ionomer-AOT comp lexes. AOT molecules were found to disrupt efficiently the cluster-for ming contacts among salt/acid groups, each of them encapsulating a sin gle salt/acid group. The AOT micelles, however, do not completely disr upt the intrachain aggregation.