Effect of cations on the diffusivity of the charge carriers in polyaniline membranes

The bulk and interfacial transport properties of PANI free-standing membranes have been investigated in acidic media with chloride as common counter-ion and with different co-ions, using the a.c. impedance technique with a four-electrode cell. The experimental data were compared to a recently proposed theoretical expression, based on use of the Nernst–Planck equation for mass transport and on slow discharge for ionic interfacial transfer. Though the only transport properties addressed in this model are the counter-ion and the polaron mobilities, experiments show an influence of the co-ion. In the case of multiple charge cations, especially Zn 2+, all mobilities are strongly reduced.