Polyelectrolyte complexes as a "smart'' depot for self-healing anticorrosion coatings

Various types of "intelligent'' self-healing anticorrosion coatings using stimuli-responsive behaviour of polyelectrolyte/inhibitor complexes are presented. Flat nanocomposite multilayers as well as colloidally-templated micro- and nanocarriers with incorporated inhibitor are employed as main building blocks for the formation of novel protective materials. The corrosion inhibitor is incorporated as a structural element (organic molecule), as an inorganic precipitate or in a porous inorganic particle. Being induced by local pH changes during corrosion development, polyelectrolyte/ inhibitor complexes afford the unique ability of active feedback and sustained release of inhibitor exactly at the corrosion-damaged sites. Elimination of the corrosive attack returns the complex layer back into the sealed state, providing effective storage and consumption of inhibitor. Insertion of complex-based elements into the coating matrix not only allows the combination of passive and active corrosion protection but also imparts the self-healing properties.