Corrosion Protection With ICPS: Mechanism, Stability and Durability of the Protective Component
Intrinsically conducting polymers (ICPs) have been discussed in recent years as corrosion protection materials or, more specifically, as anti-corrosive pigments, because of their intrinsic insolubility in water and organic solvents.1 Basically, state-of-the-art of corrosion protection tells that such materials might be either chemically or electrochemically active as a protecting material. Explanation for chemical activity is pretty obvious, because of the structural resemblance of conducting polymers, like polyaniline, polypyrrole and polythiophene derivates, with state-of-the-art (low molecular weight) corrosion inhibitor molecules.1 So, this chemical activity is based on preferred complex formation in between the conducting polymers and corroding metal surfaces or the metal ions occurring in these processes.
It is important to stress that chemical activity is mainly observed with non-doped conducting polymers, i.e., purely organic, non-charged species, with the latter being also not electrically or electronically conductive. On the other hand, electrochemical corrosion protection of conducting polymers is discussed in context with so-called active/passive metals and limitation of such activity is to the (doped) electrically conductive versions of conducting polymers, i.e., organic polymer salts of extreme brittleness and other typical salt-like properties.1