A team of scientists at the CIDETEC Centre for Electrochemical Technologies have successfully created the first self-healing polymer that can heal by itself at room temperature, without the need for external catalysts. The material could be used as an industrial adhesive or to replace similar compounds in cars, houses and electrical components to make them more fault-tolerant.
Polymers stick together thanks to so-called "cross-links" – chemical bonds that glue different polymer chains to one another. Under normal circumstances, these bonds need a source of energy such as light, pressure or a change in pH in order to form (or heal once they have been severed).
The polymer created by Ibon Odriozola and colleagues sports a key difference. Their material, a soft poly(urea-urethane) network, leverages the metathesis reaction in aromatic disulphides. This chemical reaction is naturally able to create covalent bonds at room temperature, allowing the polymer to autonomously heal without an external source of energy.
When cut with a razor blade and left to rest at room temperature, the material showed the impressive ability to quickly mend itself with 97 percent efficiency after only two hours.
The polymer showed a close resemblance with commercial compounds used as sealants and adhesives, suggesting that it could be used to replace them and considerably extend their lifetime.
Currently, the compound has a soft consistency. Odriozola and colleagues are now focusing on creating a harder version that could be used, among other things, to create plastic parts that would be highly resistant to cutting and repetitive straining.
A paper describing the polymer appears in a recent issue of the journal Materials Horizons.
The video below demonstrates the self-healing properties of the material.
Source: Royal Society of Chemistry