‘Terminator’ polymer can spontaneously self-heal in just two hours
In the future, we may praise the computer repairman on his needlework. After all, the self-healing power of skin has served life very well over the years; it could be just as powerful in other contexts, too. If we surrounded the most sensitive computer components with a sac of soft material, air- and water-tight, repairs could end with the technician suturing shut a scalpel hole.
Researcher Ibon Odriozola at CIDETEC Centre for Electrochemical Technologies has created a polymer that has the potential to lead to such a future. The material is comprised of a poly (urea-urethane) elastomeric matrix, a network of complex molecular interactions that will spontaneously cross-link to “heal” most any break. In this context, the word “spontaneous” means that the material needs no outside intervention to begin its healing process, no catalyst or extra reactant. In the experiments, a sample cut in half with a razor blade at room temperature healed the cut, with 97% efficiency, in just two hours.
The reaction, called a metathesis reaction, has led Ibon to dub the material his “Terminator” polymer, in reference to Terminator 2′s T-1000. That’s an apt comparison, since this homogenous material resembles the thick liquid of T-1000′s interior. Unlike other self-healing materials, this one requires so catalyst and no layering. There’s currently no word on how well it can heal itself over multiple separations, but so long as it’s not cut in precisely the same place twice, that shouldn’t cause too many problems.
There is potential for this technology to help extent the lift-spans of some plastic parts, things that are under a lot of repetitive strain often slowly acquire minute but growing fractures. The group’s main goal now is to make a harder version, perhaps one that could be formed into such parts itself. As it exists today, the polymer is squishy and somewhat soft. The researchers couldn’t stretch a single piece to breaking by hand, either before or after the cut, but it’s not rigid enough to make parts from just yet. (See: Stanford creates touch-sensitive, conductive, infinitely-self-healing synthetic skin.)
A good self-healing material has been one big challenge for artificial skin, something that can quickly stop up small wounds on its own. Self-healing also potentially grants to the ability to grow over time, as new units of the matrix could be incorporated as the material stretches and tears on the microscopic level. A graft of artificial skin given to a growing child might be able to grow along with them for a while. And since it allows easy surgical work, self-healing skin lets the body stay shut up tight against germs.
If its healing mechanism proves robust enough, we could even see this Terminator material injected like an adhesive or a sealant. Its impressive combination of elasticity and strength could let it bring the self-healing advantage to everything from leaky window frames to painful joints in need of some padding to stop bones from rubbing together. (See: Self-healing, self-monitoring chip rearranges circuit if damaged.)
And then there’s the possibilities for protective coatings. Inventors have long been in search of a self-healing protective coating, a top-sheet that could soak up small nicks and return to its prior state. Even the thick piece cut in the video healed with a barely perceptible “scar,” so there’s at least hope for a transparent coating that heals invisibly.
Research paper: doi:10.1039/C3MH00061C – “Catalyst-free room-temperature self-healing elastomers based on aromatic disulfide metathesis”