Dielectric Constant of a Polymerized Ionic Liquid with Rigid Side Chains

Recent experiments suggest that polymerizing ionic liquids can result in unconventional increases in the dielectric constant, yet the mechanism for this remains unclear. We probe these results with molecular dynamics simulations in LAMMPS using the Stockmayer fluid model, in which the polymers are treated as chains of charged (or neutral) dipolar spheres. We have implemented a novel method to restrict the dipole motion by treating the dipolar, ionic sidechains as rigid bodies attached to a semi-flexible backbone. We determine the effects of this constraint on the dielectric constant, dipole order and dipole correlations, and how these quantities differ from the case of freely-rotating dipoles and from experiment.