Electrostatic Manipulation of Phase Behavior in Charged Polymer Blends

Microphase separation in a binary blend of charged polymers can in principle be stabilized electrostatically, without the need for block architectures. This provides a route to control microstructure via parameters such as polymer charge density and dielectric constant. Here, we use equilibrium self-consistent field theory to map the phase behavior of a binary blend of oppositely charged polymers, which exhibits the canonical diblock copolymer ordered phases. We demonstrate how differences in the charge density, counterion valency, and the dielectric constant of the two polymers affect phase behavior in this system. In particular, we find that the phase windows for spherical phases are dramatically affected, suggesting that exotic (Frank-Kasper) spherical phases may be achievable in charged polymer blends with dielectric or charge density contrast.