Relaxation phenomena and conductivity mechanisms in anion-exchange membranes derived from polyketone

A polyketone-b-poly[N-(4 methyl-methylpyridium)-ethylenepyrroleþ][X], with X ¼ I or OH, is investigated as an example of anion-exchange membrane with potential applications in fuel cells. The polyketone starting material PK and the functionalized polyketones Pyr-FPKmI and Pyr-FPKmOH are investigated via Broadband Electrical Spectroscopy (BES) to understand the conductivity mechanism. BES signals are collected in the frequency range of 102 e 107 Hz and from 100 to 120 C. BES measurements reveal the presence of up to three interdomain polarizations phenomena, one electrode polarization event and two b dielectric relaxation modes for both wet Pyr-FPKmI and Pyr-FPKmOH. Ion conductivity for Pyr-FPKmI and Pyr-FPKmOH is found to be 0.0086 and 0.0105 S cm1 at 80 C, respectively. The overall conductivity mechanism is attributed to the superposition of two conduction pathways, via delocalization bodies and via interdomain percolation pathways, which are associated with two different physical phenomena.