Self-healing and anticorrosion coatings based on responsive polymers with metal coordination bonds

Abstract

Coatings containing corrosion inhibitors are effective materials for hindering corrosion of metals and alloys structures. However, shortcomings of these coatings include an uncontrolled leaching of inhibitors and susceptibility to mechanical damages, which lead to a shortened anticorrosion property. To overcome these issues, we prepare a new smart coating with the abilities of releasing selectively corrosion inhibitors and repairing autonomously mechanical damages. This dual-function is imparted by a pH-responsive polymer containing a corrosion inhibitor which coordinates cerium ions. Upon corrosion, the polymer releases the corrosion inhibitor and cerium which then forms insoluble cerium oxides or cerium hydroxides on cathodic sites. The corrosion rate of aluminum alloys coated with the polymer conjugate complex is ∼ 31 times lower than for the coating of the polymer conjugate that is not complexed. Self-healing after mechanical damage is enabled by the metal–ligand coordination bond between cerium ions and conjugated 8-hydroxyquinoline (8HQ), leading to a restauration of ∼ 98 % of the anticorrosion properties.