Enhancing ion transport in charged block copolymers by stabilizing low symmetry morphology

We show the enhancement of ion transport properties for charged block copolymers comprising non-stoichiometric ionic liquids by stabilizing the cubic Frank-Kasper A15 phases with space group Pm3n. The ionic liquid cations predominantly present near the micellar interfaces to increase stabilization energies of the A15 structures if they have strong attractive electrostatic interactions with the charged polymer chains. Unprecedented re-entrant phase transitions between lamellar and A15 structures occur through the electrostatic control of interfaces. Overall, the stabilization energies of the A15 structures were greater when enriched, attractive electrostatic interactions were present at the micellar interfaces. Contrary to the conventional wisdom that block copolymer interfaces act as “dead zone" to significantly deteriorate ion transport, this study establish a prospective avenue for advanced polymer electrolyte having tailor-made interfaces.