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The effect of counterions on the solution properties of two types of ionomers, one based on sulfonated polystyrene and the other based on styrene–methacrylic acid copolymer, was studied by viscosity and light scattering measurements. It was found that the order of counterion binding of ionomers in a polar solvent and the order of aggregation of ionomers in a low‐polarity solvent were the same for the same ionomer system. However, the order for the sulfonated ionomer was Li < Na < K < Cs, whereas that for the carboxylated ionomer was the opposite. This can be explained by a difference in desolvation during anion–cation interaction and by considering site‐binding in a polar solvent and the association of ion pairs in a low‐polarity solvent. These findings for ionomer systems are parallel to the association behavior of small ions in water, cation affinity in crosslinked resins, and counterion binding of polyelectrolytes in water.

It is shown that ion-dipole interactions can lead to miscibility enhancement in polymer blends.While polystyrene is not miscible with poly(ethy1ene oxide) or poly(propy1ene oxide), styrene ionomers show very high miscibility with t h e materials at low alkylene oxide contents (10 w t %) and high, though not complete, miscibility at higher loading levels. For these systems it is seen that the glass transition temperature (from G" peak positions) of the styrene ionomer is depressed dramatically with increasing alkylene oxide contents and that the glass transition of the alkylene oxide rises appreciably (in most cases) with increasing styrene ionomer content. Increases in ion content at constant styrene levels increase the miscibility. The degree of miscibility enhancement is comparable to that achieved in hydrogen-bonded systems. Finally, molecular weight effects observed here are quite similar to those seen in other blend systems.