The Protection Zone: A Long-Range Corrosion Protection Mechanism around Conducting Polymer Particles in Composite Coatings: Part I. Polyaniline and Polypyrrole

In recent years Intrinsically Conducting Polymers (ICPs), such as polyaniline and polypyrrole, have become key materials in the search for high-performance coatings for the protection of metals from corrosion. In this work, by means of dedicated model samples, we have found that disconnected ICP particles in composite coatings applied on iron and zinc are capable of inhibiting the oxygen reduction in their vicinity, establishing a region where no or only very slow delamination occurs, i.e. a "protection zone" is created, which relies on the ICP's high potential and its redox activity. The efficiency of this novel protection mechanism may depend on the ICP type, thickness or counter-anion, and is here analyzed by means of Kelvin probe based investigations.