Ionic Correlations in Polymer Nanostructures: From Charged Block Copolymers to Supramolecular Ionic Crosslinking

Ionic interactions provide a powerful and tunable means to direct polymer phase behavior, with applications in solid-state batteries and plastic recycling. This talk explores two key systems—neutral-charged block copolymers and ion-functionalized polymer blends—using an ionic correlation-augmented self-consistent field theory. For AB block copolymers with uniformly charged A-blocks, we demonstrate that ion correlations induce a "chimney-like" phase diagram, but lowering the dielectric constant of neutral B-blocks suppresses the "chimney-like" feature. Notably, smaller counterions promote localized ion distributions, leading to a variety of superlattice hierarchical nanosctructures, including clusters, alternating layers, to concentric cylindrical and spherical shells. Furthermore, tuning the charge pattern enables stabilization of the highly frustrated “plumber’s nightmare” structure. In the second part, we apply our theory to the binary polymer blends where each chain is end-functionalized with a single oppositely charged group. Strong ion correlations effectively link the polymers, inducing phase behavior resembling that of neutral block copolymers. However, the order-disorder transition occurs at a significantly lower critical χN than in neutral systems. Additionally, ion localization persists even in fully miscible blends, and we discuss the transition from macro- to microphase separation. These findings are in general agreement with experimental data reported in the literature, and highlight the critical role of ionic interactions in tailoring polymer self-assembly for advanced materials and sustainability.