Mesoscale hydrated morphology of perfluorosulfonic acid membranes

Fuel cells are expected to play an important role in global carbon neutralization and future social development with high conversion efficiency and zero emissions. The core of the fuel cell is the proton exchange membrane (PEM). However, the unclear of the proton transport mechanism in PEMs limits the development of membranes with improved performance. Perfluorosulfonic acid (PFSA) membranes are currently the most widely used type of PEM, and exhibit varying proton transport capabilities with various chemical structures. In this study, the hydration morphology of several PFSA membranes was studied using dissipative particle dynamics. The result shows that under low water content the hydrophilic and hydrophobic phases separated and the water clusters are relatively isolated. The increased water content formed hydrophilic channels, while the increase in equivalent weight decreases the water cluster size and improves water dispersion. Aciplex 1128 shows great variation owing to the presence of a long sulfonic acid terminated side chain in water cluster size and dispersion compared with Nafion. The average diffusivity and mean square displacement results showed similar results. These results will promote the development of high performance PEM for fuel cells.