Martini Coarse-Grained Model for Poly(alkylimidazolium) Ionenes and Applications in Aromatic Compound Extraction

Ionenes are a class of ionic polymers in which the charged groups are incorporated within the polymer backbone. The combination of strong electrostatic interactions and the underlying molecular architecture can lead to a wide range of thermophysical behaviors, with applications ranging from gas separation membranes to electrochemical systems. In order to accelerate the investigation of these materials, we propose a coarse-grained molecular model for a poly(alkylimidazolium) ionene, based on the Martini 3 force field. Although all-atom molecular simulations of ionenes have been previously performed, to the best of our knowledge, coarse-grained models of imidazolium-based ionenes are yet to be developed or tested. We perform benchmark comparisons against all-atom molecular dynamics simulations, and then, we use the more computationally efficient coarse-grained model to investigate the ionene performance for the selective absorption of benzene from an octane-benzene mixture. Our results show good performance of poly(alkylimidazolium tetrafluoroborate) for benzene extraction from the mixture, in terms of selectivity and solubility.