Synthesis and Dielectric Studies of {Nafion/[(ZrO2).(Ta2O5)0.120]5%ZrO2} Composite Membrane

The composite membranes based on {Nafion/[(ZrO2).(Ta2O5)0.120]5%ZrO2} has been prepared by solvent casting technique. It has been characterized by dielectric spectroscopic studies in the frequency range 40 Hz to 10MHZ at different cell temperature (25 to 105 °C) and dew point at Constant pressure. The conductivity of the composite membrane has been found to improve with increasing atmospheric humidity though the dependence was much smaller than that for Nafion membrane, far all cell temperatures. The maximum conductivity of the composite membrane has been found to be, 2x10-1S/cm at a dew point of 99°C with cell temperature of 105°C. The spectroscopic plots of real and imaginary parts of permittivity reveal the presence of two electrode polarizations one in lower and another in higher frequencies. After the subtraction of the electrode polarization, the spectra shows 'a ' relaxation at lower frequencies, attributed to cooperative segmental rearrangements in the main backbone fluorocarbon chains of Nafion and 'a' relaxation at higher frequencies, assigned to local motions of aggregated polar groups of Nafion. Thus this paper shows the significance of dependence of conductivity and relaxations on relative humidity at controlled temperature and pressure.