Effect of Hydrodynamic Interactions and Flow on Charge Transport in Redox Active Polymer Solutions

Redox-active polymers (RAPs) are a subclass of polyelectrolytes that can store charge and undergo redox self-exchange reactions. They are of great interest in the field of redox flow batteries due to their ability to quickly charge and discharge, their chemical modularity, and their molecular size. However, the numerous physicochemical attributes of RAPs are an opportunity to design at the molecular level for efficient charge transport, which require a fundamental understanding of charge transport mechanisms for redox flow batteries. This work has improved previous models by incorporating both hydrodynamic interactions (HI) and out-of-equilibrium dynamics to resemble flow battery conditions more closely. This has been achieved using the conformationally averaged Brownian Dynamics simulation method paired with Monte Carlo. The model is used to show that HI is an important feature when charge hopping is not the major mechanism for charge displacement. Furthermore, it has been shown that the flow conditions may result in either enhanced or decreased transport – depending on the fraction of charges present on the RAP chain. This model is a first of its kind in that both charge transport and flow is simultaneously modeled in an RAP solution.