‘Terminator’ Polymer Heals Without Help
Taking a cue from early ’90s movie magic, scientists in Spain have reported the first self-healing polymer that “spontaneously and independently repairs itself without any intervention.”
Nicknamed the "Terminator" polymer as an homage to the shape-shifting robot from the sci-fi series, the new material could be used to improve security and lengthen the life of plastic parts in products.
Based on a poly(urea-urethane) type composition, the new polymer was discovered by researchers at the CIDETEC Centre for Electrochemical Technologies, a research alliance based in San Sebastian, Spain.
While self-healing polymers aren't new, they usually require an external catalyst—such as heat, light or a specific environmental condition—for the cross-linking healing mechanism to work.
"The fact that poly(urea-urethane)s with similar chemical composition and mechanical properties are already used in a wide range of commercial products makes this system very attractive for a fast and easy implementation in real industrial applications," the researchers said, according to the Royal Society of Chemistry.
Terminator's 2 Experiments
According to the authors, the polymer acts as a Velcro-like sealant with a 97 percent healing efficiency in two hours.
After cutting the material—a cylinder made from poly(urea-urethane)—into two pieces with a razor blade and pressing them back together, the material was unbreakable after two hours when stretched by hand, the team demonstrated in a video presentation.
After being cut in half with a razor blade, the polymer heals on its own in two hours sitting on a table in room temperature, according to a video presentation.
Self-healing polymers that can spontaneously heal without a catalyst have never before been reported, the authors said. They reported that the regeneration occurs from a metathesis reaction of aromatic disulphides, which naturally exchange at room temperature, without the need for any external intervention such as heat or light.
In a second experiment, the researchers "chopped" an identical cylinder very slowly by the gravitational force of a copper filament attached to a weight. By the time the filament had gone completely through the cylinder, reseachers report that the first had already self-mended completely.
The research, "Catalyst-free room-temperature self-healing elastomers based on aromatic disulfide metathesis," is published in Materials Horizon. The authors are Alaitz Rekondo, Roberto Martin, Alaitz Ruiz de Luzuriaga, Germán Cabañero, Hans J. Grande and Ibon Odriozola.
The researchers say they plan to continue working on this self-healing polymer to develop harder materials by incorporating reinforcements or other technologies.
The work was was developed in the framework of the SHINE European project, where IK4-CIDETEC participates as a partner in a consortium of various European companies, research centers and universities.