New Rubber-like Material Can Heal Itself

By Andrea Thompson, LiveScience Staff Writer

posted: 20 February 2008 1:00 pm ET

It sounds likes something from a sci-fi movie: a rubber-like material that can fuse itself back together after being snapped in two.

As anyone who's shot a rubber band across a room knows, standard rubbers are very flexible — they can stretch by several hundred percent.

But if you've pulled just a little too hard on that rubber band, you also know it can suddenly (and painfully) snap in two.

Ludwik Leibler of the Industrial Physics and Chemistry Higher Education Institution in Paris and his colleagues have solved the broken rubber band problem by creating a material that stretches like rubber, snaps like rubber, but then will mend itself if its two broken ends are brought back together.

The new stuf, made from fatty acids and urea, is translucent and can have a yellowish tint, Leibler says.

The bonds between the molecules in the material, called hydrogen bonds , are what give 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 explained. If the two ends of the broken piece are brought back together, the molecules will re-partner with molecules on the other end of the break. But 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.

If the material does re-fuse, it retains the same amount of stretch as it did before and, "you can repair it many times," Leibler said.

The rubber material is currently being produced on a test basis by a company called Arkema, Leibler told LiveScience. His team envisions the material being used in toys, which children are prone to breaking, perpetually-closed bags, or as an adhesive .