London, Feb 21 : Scientists have created a type of rubber that can fuse itself back together after being snapped in two.
Ludwik Leibler of the Industrial Physics and Chemistry Higher Education Institution in Paris and his colleagues have created a material that stretches like rubber, snaps like rubber, but then mends itself if its two broken ends are brought back together.
Made from fatty acids and urea, the new material is translucent and can have a yellowish tint, and can self-heal at room temperature in around 15 minutes by simply pressing the damaged pieces together.
The bonds between the molecules in the material, called hydrogen bonds, are responsible for giving the new rubber its self-healing ability. They form linear links, called chains, between some molecules, as well as cross-links between those chains, creating a "supramolecular" network of smaller molecules.
When the material is broken, the molecules on each side of the break lose their partners, and "so they look for partners to make these hydrogen bonds," Leibler said.
When the two ends of the broken piece are brought back together, the molecules re-partner with molecules on the other end of the break.
However, if they aren't brought together within several hours of the break, the molecules will just pair up with other molecules on their respective end, and the material can no longer be repaired.
Leibler explained that if the material does re-fuse, it retains the same amount of stretch as it did before and, "you can repair it many times."
"It is a very simplistic concept, and using renewable resources is really nice. It's a good indication that you can rip things apart and put them together," Nature quoted Oren Scherman, a chemist at the University of Cambridge, who will be running a session on self-healing materials at the upcoming American Chemical Society meeting in New Orleans, as saying.
The rubber material is currently being produced on a test basis by French chemical company Arkema, Leibler said.
His team would like to see the material being used in toys, which children are prone to breaking, perpetually closed bags, or as an adhesive.