(576c) Atomistic Simulations of Ion Transport in PsbP2VP Functionalized Lamellae

In microphase-separated electrolytes formed by block copolymers, ion mobility in bulk as well as at the interface is crucial to conductivity. Computational simulations provide the opportunity to understand the mechanism of ion transport. Coarse-grained models and field theory can capture the phase behavior of polymer electrolytes but miss detailed interactions between polymers and ions. On the other hand, computational limitations make it difficult to obtain equilibrated morphologies with atomistic details. Current atomistic simulations of polymer electrolytes mainly focus on ion transport in the bulk at small length scales. Little is known about ion behavior at interfaces between different polymer domains. To study ion transport of polymer electrolytes with nanostructure, we generate an equilibrated morphology with the theoretically-informed coarse-grained (TICG) model and then map atom-level resolution pertaining to the poly(styrene-block-2-vinylpyridine/n-methyl pyridinium, iodide) (PS-b-P2VP/NMP⁺ I^-) system.

Molecular dynamics (MD) simulations were performed on functionalized atomistic PS-b-P2VP/ NMP⁺ I^- —lamellae and disordered—and P2VP/NMP⁺ I^- homopolymer systems. We study the functionalized PS-b-P2VP at various percentages of functionalization and with different water weight percentage, which changes the coordination environment of the ions. Finally, we investigate the density distribution and mobility of polymers, ions, and water molecules throughout the lamellae. Specifically, we find the residence time of ions in solvation sites at the interface to be shorter than those in the bulk.