Unlike previous attempts to create self-healing polymers, based on microspheres filled with a bonder, this time Mr. Ghosh and Mr. Urban have discovered a chemical that reacts to mechanical forces.
The idea is that, when scratched, this polymer re-creates chitosan (a common molecule, found in the shells of lobsters and shrimps). It needs ultraviolet light to work its magic. Your car could get a scratch at your parking lot and one hour later you'll find it self-repaired. From the comments I've read, the technology seems promising. The abstract says:
Unfortunately, it works only once: repeated scratchs cannot be healed. For a more simple article or if you don't have a Science subscription, you can read Mr. Urban comments here."These materials are capable of repairing themselves in less than an hour and can be used in many coatings applications, ranging from transportation to packaging or fashion and biomedical industries."
As a side note, chitosan is used nowadays as an emergency blood clotting agent, sold as CELOX. According to the description I read, you can create the bandage using grounded shrimp shells and vinegar on top of a regular gaze.
Chitosan bandage
