Steady-state-current impedance spectroscopy of plasticized PVC membranes containing neutral ion carriers

Impedance spectroscopy measurements on plasticized PVC ion-selective membranes containing neutral carriers provided evidence for both bulk and interfacial features. Under steady-state currents, the systems showed concentration polarization of neutral carriers and ionic species. The shortage of neutral carriers at one of the interfaces was correlated with the presence of a low-frequency kinetic semi-circle and a Warburg impedance. The changes in ionic concentration profiles were associated with an increase in bulk membrane resistance and Warburg impedance.