Block ionomer complexes formed between the block copolymers containing poly(sodium
methacrylate) (PMANa) and poly(ethylene oxide) (PEO) segments and poly(N-ethyl-4-vinylpyridinium
bromide) (PEVP) were investigated. The data obtained suggest that (i) these systems form water-soluble
stoichiometric complexes; (ii) these complexes are stable in a much broader pH range compared to the
polyelectrolyte complexes prepared from homopolymers; (iii) they self-assemble to form the core of a micelle
comprised of neutralized polyions, surrounded by the PEO corona; (iv) they are salt sensitive since they
fall apart as the salt concentration increases beyond a critical value; and (v) they can participate in the
cooperative polyion substitution reactions. Therefore, these complexes represent a new class of hybrid
materials which combine properties of polyelectrolyte complexes and block copolymer micelles
