Table 1.

Different type of self-healing coating, key characteristics, and potential application.

Sl No.	Type of Self-Healing Coating	Characteristics	Potential Applications
1	Micro/nano polymer capsules to load the healing agent.	Popular self-healing coatings. Preparation of capsules can be tedious. Challenges in stability.	An anticorrosive coating to enhance the durability of metallic structures.
2	Multi-shelled microcapsules to load the healing agent.	Good resistance to salt water.	Waterborne self-healing coatings for automobiles.
3	Porous inorganic materials with functionalized orifices to load the healing agent.	Commercially available porous inorganic materials can be used directly. Controlled release of healing agent.	pH sensitive self-healing coating for metals.
4	Core−shell nano- and micro-fibers as healing agent containers	Sufficiently large amount of healing agent could be loaded in core-shell fibers.	Anticorrosive coating for large scale industrial applications.
5	Layer-by-layer coating to immobilize healing agent/corrosion inhibitor	Thin coating offers long term corrosion protection.	To protect aluminum alloys used for aerospace applications
6	Cellulose nanofibers to immobilize healing agent/corrosion inhibitor	Ecofriendly coating technology.	For submarine applications.
7	Halloysite nanotube as healing agent containers	Economic and green coatings. Halloysite nanotubes act as reinforcing agent for the coating.	Anticorrosive paint for commercial applications.
8	Natural oils as healing agents	Green and economic.	Anti-corrosive metal coatings for scalable industrial applications.
9	Henna leaves extract as corrosion inhibitor	Eco-friendly corrosion inhibitor.	Suitable to protect variety of metals exposed to a wide range of electrolytes.
10	Graphene oxide (GO) based microcapsules as healing agent container	Mechanical stability and high loading capacity.	Protect metal parts used in submarine vehicles from alternating hydrostatic pressure (AHP).