"Healing is a matter of time, but sometimes also a matter of opportunity."
Hippocrates, the "Father of Medicine"
Our bodies have the capacity to heal themselves, being covered in a remarkable self-healing material—skin. Man-made materials, though, did not have this benefit until American Scott White and his University of Illinois team created self-healing polymers in 2001.
Self-healing materials are composites consisting of microcapsules that contain a healing agent and small amounts of a catalyst, which allows the healing agent to repair damage to the material. Usually a material deteriorates over time due to damage from microcracking—faults that ''allow larger cracks to develop. With self-healing materials, microcracks rupture the microcapsules, the healing agent comes into contact with the catalyst, and the fault is filled in, These materials boast a long lifespan and are expected to prove invaluable, particularly for artificial organs and use in the space industry.
Self-healing materials have a finite life as the healing agent they hold is limited. Once healed, they have about 60 to 75 percent of their original strength, but as they are up to 20 percent stronger than equivalent normal materials, they are still viable. White's ultimate goal is to create a "bio-mimetic" substance with a circulatory system to transport recovery materials to where they are needed. Such a material would have an indefinite lifespan.
