IMPEDANCE SPECTROSCOPY OF A PERFLUOROSULFONATED IONOMER POLYMER ELECTROLYTE

Impedance spectroscopy was performed on solution cast perfluorosulfonated ionomer (PFSI) membranes in an attempt to characterize their electrical properties, and an overall account of the structure-property relationships of as-received and solution cast PFSI will be presented in this report. No large scale massive ion motion occurred in the solution cast PFSI. Instead, only polymer chain polarization was observed and has been determined to be the gamma-relaxation occurring at ca 215-235 K depending on the membrane type. The room temperature d.c. conductivity of the solution cast membranes is lower by at least 4 orders of magnitude (approximate to 10(-7) to 10(-6) S cm(-1)) than that of the as-received and converted forms of membranes. Wide angle X-ray diffraction revealed that structural changes have occurred in the solution cast PFSI.