Magnetic-field-induced deactivation of polypyrrole films in repeated redox cycles

Magnetic field effects on the durability of anion-doped polypyrrole (PPy/anion) films were studied by measuring successive cyclic voltammograms in a cryocooler-cooled superconducting magnet. The deactivation, which means positive shifts of the anodic peak potential, was observed in PPy/ClO4- and PPy/Cl- films under the magnetic fields of 2 and 5 T. This magnetic-field-induced deactivation has a novel aspect that is an accumulative effect of the magnetic fields. On the other hand, the degradation of PPy/p-toluenesulfonate films, which means a current decrease in the voltammograms, was not affected by the magnetic field of 5 T.