Quantitative Structure Analysis of Polymerized Ionic Liquids with Atomistic Simulations

The design of solid-state electrolytes for electrochemical applications that utilize polymerized ionic liquids (polyILs) would greatly benefit from a molecular-level understanding of structure-property relationships. We herein use atomistic molecular dynamics simulations to investigate the structural properties of a homologous series of poly(n-alkyl-vinylimidzolium bistrifluoromethylsulfonylimide) poly(CnVim Tf2N). Excellent X-ray S(q) agreement is found in terms of peak position and shape. The quantitative cluster analysis along with color-coded snapshots vividly demonstrates the morphology evolution. Moreover, we exploit the selective labeling neutron scattering to afford further insight. The neutron scattering profiles markedly depend on the isotopic substitution pattern. The neutron S(q) of the backbone deuterated samples reveal the most noticeable low-q peak. We also investigate a model ammonium based polyILs and anion effect. We hope these insights will pave a path forward towards the rational design of future polyILs for electrochemical devices.