Using Drude\nOscillators to Capture Ion Solvation in\nGeneric Coarse-Grained Molecular Dynamics Simulations of Polymer Electrolytes

Generic bead–spring models with Lennard–Jones\ninteractions\nare commonly used to study uncharged polymeric materials. However,\nincorporating ions into polymer systems requires additional model\nfeatures to address their long-ranged Coulomb interactions and their\ninteractions with polarizable polymers. This study integrates the\nDrude oscillator model into coarse-grained molecular dynamics simulations\nto capture features of ion solvation in polymers. Specifically, we\ntreat coarse-grained beads as polarizable entities with internal dipoles;\neach bead contains a Drude core bonded with a stiff spring to an oppositely\ncharged Drude particle that does not leave the Lennard−Jones\ndiameter of the core. We first demonstrate the feasibility of this\napproach in simulations of neat polymers, exploring dielectric constants\nranging from 2 to 12. To manage strong local interactions in high-polarizability\nsystems with ions, we propose combining this approach with implicit\nstrategies such as adjusting the background dielectric constant and\nscaling down ion charges. By combining these explicit and implicit\nmethods, we can gain control over structural features like ion clustering\nand peak heights in radial distribution functions, enhancing our ability\nto model features of ion solvation and dielectric response in polymer\nsystems.