Including stiffness and glass transition temperature differences in a coarse-grained model of salt-doped block copolymer electrolytes

Salt-doped block copolymers are promising solid electrolytes because of their ability to form two distinct microphases which allow for ionic conductivity along with significant mechanical strength. Our prior work focused on understanding how key physical parameters, such as the dielectric strength of the polymers as modeled through scaled Coulomb interactions and an ion-monomer solvation potential, act to set the overall trends in structural and dynamic properties. Our generic coarse-grained model captured the most salient structural and dynamic trends in these systems such as how ion conductivity and domain size change as a function of ion concentration. Here, we also include stiffness and glass transition temperature differences between the two blocks to match these relative differences in salt-doped polystyrene-b-poly(oligo-oxyethylene methyl ether methacrylate) systems. Specifically, by adding angle potentials and tuning the Lennard-Jones and solvation potential strengths, we are able to achieve glass transition temperatures and domain sizes that resemble those observed in experiments, allowing us to better understand local ion mobility in these systems.