February 20, 2008

Chemists Create Rubber that Heals Itself

A new rubber-like material created with the ability to "heal" itself is paving the way for the development of a wide variety of new products.

Polymer chemist Ludwik Leibler developed the "supramolecular rubber" with his colleagues at the Industrial Physics and Chemistry Higher Educational Institution (ESPCI) in Paris, France.

When light pressure is applied to the fractured pieces of rubber at room temperature, they form a hydrogen bond and about 15 minutes later become one piece that is just as strong as it was before being separated, according to Leibler.

"You can feel the material mending itself when you hold the fractured sides together," Leibler said. "It's a very strange feeling."

When designing the material, the team got rid of the ionic and covalent bonds, thus isolating the hydrogen bonds, which are the only type of bonds which can be re-formed.

Conventional rubbers consist of crosslinked polymer molecules using covalent, ionic, and hydrogen bonding.

The result is a brownish-yellow rubber-like material. The primary disadvantage of the material is that the process of stripping its bonds down to hydrogen alone causes it to be somewhat weaker than traditional rubber.

"It is important to stress that the material is not self-adhesive," Leibler said. "The surfaces of the material are never sticky to the touch and feel like a rubber band or a plastic bag. Self-mending is possible even 12 hours after the fracture occurred."

Ideas for the material's application are perpetually forming with some have suggestions including chipless paint, virtually invincible car tires, shoes capable of fixing nicks or scuffs on their own, and even a new breed of resealable bags.

"You don't need a zip when you can make a resealable hole in it," Leibler says.


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Watch the material in action

Industrial Physics and Chemistry Higher Educational Institution (ESPCI)