Dilute solution viscosity, solid-state rheometry, and H-1-NMR linewidth analyses are used to assess the effect of ion-dipole (R'OH/NR4+Br-) interactions on the intensity of ion-pair aggregation within a series of new isobutylene-based tetra-alkylammomium bromide ionomers. While inductive/field effects on hydroxyl group polarization exert no appreciable influence on ionomer properties, sparingly-soluble, hydrogen-bonding additives are shown to relieve heightened aggregation by interacting selectively with bound ion-pairs as opposed to the bulk polymer matrix. (c) 2005 Wiley Periodicals, Inc.