Self-healing materials bring with them the promise of scratched touchscreens that fix themselves, broken circuits that start working again, and even buildings that are able to fill any cracks that appear in their structure unaided. What you may not have realized is in order for these healing processes to happen, those materials end up reacting a lot like our skin and blood does after an injury.
The process relies on microcapsules that are 20 microns or smaller in size, which when a crack is detected turn from a solid to a liquid and form a synthetic clot in the material. That clot then sets, filling the crack and healing the “wound” in some cases to the point where the material is stronger than it was previously.