Molecular dynamics simulations of microstructure and transport properties of sulfonated poly-p-phenoxybenzoyl-1,4-phenylene membrane and their comparisons to sulfonated poly(ether ether ketone) membrane

Abstract

Molecular simulation techniques have been used to study the microstructure and dynamic properties of sulfonated poly-p-phenoxybenzoyl-1,4-phenylene (sPPBP) membrane, and the results have been compared with those for the sulfonated poly(ether ether ketone) (sPEEK) membrane. It is shown that the phase-segregated morphology of the hydrated membranes was mostly affected by the hydration level, while the temperature had a limited effect. The sPPBP membrane had more phase segregation and higher values of proton conductivity than the sPEEK membrane. While the sPPBP membrane displayed higher H2 permeability, its conductivity in contact with diffused H2 still exceeded that of the sPEEK membrane. The results indicate that the presence of the flexible pendant side chain in the sPPBP membrane had a determining effect on its microstructure, and brought about an improvement of its dynamic properties.