Assessing the moisture barrier properties of polymeric coatings using electrical and electrochemical methods

Organic coatings, which are applied for the purposes of corrosion protection, provide a barrier to water, ions, and reducible species. The author reviews the electrical and electrochemical methods which have been used to monitor and quantify the transport of ions and water through the film, the electrochemical reactions beneath the film, and ultimately the barrier properties of the coating. These methods have included open-circuit potential, resistance, capacitance, and impedance measurements. Due to the importance of electrochemical impedance spectroscopy to film assessment and the multidisciplinary nature of the field, the basic principles of impedance are included in this review