抄録
Using two different types of ionomers which are composed of perfluorosulfonic acid (PFSA) and hydrocarbon (HC), we constructed systems of the ionomers on Pt catalyst surface, and investigated water content dependence on oxygen permeability in the ionomers using molecular dynamics simulations. We have found that the oxygen permeability of the PFSA ionomer is better than that of the HC ionomer. Moreover, the oxygen permeability decreases as water content increases in the both ionomers. Next, we analyzed density distributions of the ionomer components and oxygen solubility in the ionomers. As a result, in the PFSA ionomer, the oxygen permeability decreases because the oxygen solubility decreases due to the increase in the solvent molecules. On the other hand, in the HC ionomer, the solvent molecules accumulate on the surface of high-density polymers and block the oxygen permeation.
