New coatings will have a lot of practical applications and could coat anything that can be scratched including electronics, aircraft, cars, steel etc. The self-healing coatings could minimize upkeep and repair on a variety of products, saving consumers money and reducing waste.
Coatings can provide protection for a material from environmental exposure. Thus, when damage occurs (often in the form of microcracks), environmental elements like oxygen and water can diffuse through the coating and may cause material damage or failure. Microcracking in coatings can result in mechanical degradation or delamination of the coating, or in electrical failure in fibre-reinforced composites and microelectronics, respectively. As the damage is on such a small scale, repair, if possible, is often difficult and costly. Therefore, a coating that can automatically heal itself (“self-healing coating”) could prove beneficial by automatic recovering properties (such as mechanical, electrical and aesthetic properties), and thus extending the lifetime of the coating.
Examples of approaches regarding self-healing materials which can be applied to make “self-healing” coatings are microencapsulation, the introduction of reversible physical bonds such as hydrogen bonding, ionomers, chemical bonds.
Microencapsulation is the most common method to develop self-healing coatings. The most common application of this technique is proven in polymer coatings for corrosion protection. Corrosion protection of metallic materials is of significant importance on an economical and ecological scale.