The concept of self-healing polymers isn't new, but a researcher says his proposed material, which combines repair and sensing attributes into one polymer that 'bleeds' when damaged and heals in sunlight, is novel.

Marek W. Urban, a professor at the University of Southern Mississippi's School of Polymers and High Performance Materials in Hattiesburg, MS, initially published his findings in the journal, Nature Chemistry, in January 2012. That paper described a "reversible covalent reaction in which two oxygen-insensitive radicals combine to form a carbon-carbon bond provides the mechanism by which a polymer gel can self-heal at room temperature without the need for any external stimulus."

In March, at the 243rd National Meeting and Exposition of the American Chemical Society (ACS), Urban provided additional details on the development, describing copolymer films that when scratched change color from clear to red in the damaged area. Then, when exposed to sunlight, temperature, and/or acidic vapors, the damaged area repaired itself, returning to the initial colorless appearance. Urban said the process is reversible and functions through the ring-opening-closure of spironapthoxazine (SNO) segments to form merocyanine (MC), which are recovered back to the SNO form.

A University of Southern Mississippi article on the technology speculated that self-repairing surfaces could be applied in a variety of products, including cell phones, laptops, and military weapons. In the same article, the professor said the initial concept came to him in a dream. "I dreamed of developing this after thinking about how human skin repairs itself when damaged, and how blood coming from the injury works as a sign of that damage," Urban said in the article. "Sometimes, damage to material may not be visible to the human eye, but with the release of the colors that mimic bleeding we have a warning of damage."

Urban sees additional potential future usage in vehicles, including cars, planes and spacecraft, as well as large infrastructure, where seeing structural damage is vital.