STEADY-STATE-CURRENT IMPEDANCE SPECTROSCOPY OF PLASTICIZED PVC MEMBRANES CONTAINING NEUTRAL ION CARRIERS

Impedance spectroscopy measurements on plasticized PVC ion-selective m embranes containing neutral carriers provided evidence for both bulk a nd interfacial features. Under steady-state currents, the systems show ed concentration polarization of neutral carriers and ionic species. T he shortage of neutral carriers at one of the interfaces was correlate d with the presence of a low-frequency kinetic semi-circle and a Warbu rg impedance. The changes in ionic concentration profiles were associa ted with an increase in bulk membrane resistance and Warburg impedance .