The corrosion of metallic materials is of significant importance on an economical and ecological scale.[1] A straightforward way to protect metal against corrosion is the application of coatings, which act as barriers to water and ions that cause corrosion. Once the coating is damaged, water and ions can freely reach the metal surface, thus initiating corrosion and causing a breakdown of the coating. To enhance the corrosionprotection performance of the coatings, corrosion inhibitors are added to the coating systems. The most efficient corrosion inhibitors are based on Cr VI+. However, the use of Cr VI+ has now been widely restricted by law in the European Union due to ecological and toxicological issues.[2] This fact has initiated intensive research activities in the field of self-healing coatings in the search for an alternative to the use of Cr VI+ for corrosion protection.[1a, 3]

Self-healing coatings investigated so far are based on nanocontainer or fiber systems that store self-healing agents. In most of the systems the release of the self-healing agent occurs as a result of mechanical damage.[4] However, not all mechanical damage leads to corrosion and corrosion is not necessarily initiated at mechanical cracks. Ideally, the release of self-healing agents should only take place when corrosion is initiated. Triggers for sensing the corrosion of a metal system that have been investigated in depth are the change of pH or change of ionic strength.[5] But the most reliable and caseselective trigger is the change of the electrochemical potential, as it always and only decreases when corrosion occurs. For instance, conducting polymers (CP) can store active anions as counter-charge to the oxidized polymer backbone, which can be released upon onset of corrosion and subsequent reduction of CP.[6] Considerable research has been conducted on CP for corrosion protection, however there are three crucial points which must be taken into consideration: 1) The efficiency of release of anionic inhibitors is based on their ionic mobility and has to compete with cation incorporation in the CP, which is usually the preferred situation. 2) Due to fast cation incorporation, electropolymerized CP films with continuous ionic networks may even enhance corrosion and can lead to a fast breakdown of the coating system.[6e-h] 3) CPs applied on non-noble metals such as zinc tend to react with the metal. Consequently metal and CP