Structure and Thermodynamics in Associating Model Ionomer Solutions

Abstract

We present an overview of the current research on structure-property relationships of ionomer solutions. Viscometric measurements of ionomers in nonpolar solvents show a strong intermolecular association even at low concentrations. Small-angle neutron scattering (SANS) and quasi-elastic light scattering (GELS) experiments were performed on model telechelic ionomer solutions to investigate this association phenomenon. The results show that with increasing polymer concentration both the extent of association and the size of the associating particles increase. During association the single chain dimensions increase until a plateau value that extends into the bulk is reached at higher concentrations. The Flory-Huggins interaction parameter shows strong concentration dependence, increasing with decreasing concentration. Due to association the diffusion of the particles in solution decreases which results in reduced mobility. Combination of SANS and QELS shows that, at all association levels studied, interchain association leads to formation of highly extended clusters