Modeling the Impact of Sulfonate Concentration on Proton Diffusion in Hydrated SDAPP
Jennifer A. Clark, Lauren J. Abbott, Amalie L. Frischknecht
Sandia National Laboratories
The growing focus on clean energy has spurred renewed interest in improving membranes for energy applications. We focus on polymer membranes that facilitate ion transport in fuel cells. The DOE desires a polymer that is chemically and mechanically stable with high proton conductivity. Sandia's sulfonated Diels-Alder polyphenylene (SDAPP) has material properties that are closer to DOE targets, but not ideal. Our goal is to apply a coarse-grained model to simulate the dependence of proton diffusion on various factors. Previous work has shown that diffusion is mechanistically dependent on sulfonation and hydration levels, as well as the resulting morphology of the polymer 1. We tuned a model capable of simulating proton coordination and diffusion 2 to our system. This model uses Dissipative Particle Dynamics (DPD) in conjunction with a Morse potential to model proton coordination. From this model, we will then gain mechanistic insight into how the sulfonation and hydration of the polymer affect the proton transport properties of the membrane. These insights will help to improve the future design of proton-conducting membranes.
1 Macromolecules 50, 1184−1192 (2017)
2 The Journal of Chemical Physics 144, 014902 (2016)