The ionic conductivity of the membranes was calculated from Potentiostatic Electrochemical Impedance Spectroscopy (PEIS) measurements at 25 o C of membranes swollen with 0.1 M LiCl solution for at least 12 h. Each swollen membrane was sandwiched in a 2-electrode set-up and an alternating 10 mV sine wave in the 1 MHz to 100 mHz frequency range was applied. The ionic conductivity was calculated from the ohmic resistance as measured from the Nyquist plot, taking into account the electrodes area and the thickness of the membrane.