Electrochemical impedance spectroscopy for characterization of coatings with intrinsically conducting polymers

The method of electrochemical impedance spectroscopy (EIS) was applied to investigate the behaviour of a thin intrinsically conducting polymer film (ICP) deposited on a metal substrate. Especially the conductivity, the redox properties, the anion release properties, and the corrosion protection of a coating with and without ICP film on an iron or steel substrate were studied. Combined with other electrochemical methods, the reactions taking place at an injured surface area of the coated iron were studied. The corrosion protection mechanism of polythiophene could be explained.