Structural changes of perfluorosulfonic acid polymer membrane (PFSA) under gamma-irradiation

A perfluorosulfonic acid (PFSA) polymer membrane is an attractive proton-conducting material for polymer electrolyte to be used in fuel cells. In this study the effect of gamma irradiation on the structural changes in perfluorosulfonic acid membrane was investigated. The obtained results showed that the membrane structure changed by increasing the adsorbed dose. The irradiation effects on structural changes were investigated by optical absorption measurement in the wavelength of 190~500 nm, Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction. The optical absorption measurement showed an increase in the absorption bands intensity by increasing the adsorbed dose. Moreover, the FT-IR spectra showed a novel absorption band at 1773 cm-1 after the irradiation and the XRD results indicated crystallinity improvement by increasing the absorbed dose. Vickers microhardness test showed that the hardness increased by increasing the absorbed dose.