Friday, February 22, 2008
Rubber With Heal Thyself Properties
Filed under: in the news...
Dr Leibler, along with colleagues at the Industrial Physics and Chemistry Higher Educational Institution (ESPCI) in Paris, and with the help of Arkema corporation, have developed a remarkable material that has similar properties to rubber, plus the ability to naturally, and without any glue, to recombine itself back together if cut.
A piece of normal rubber, says Dr Ludwik Leibler, who headed the research, is actually a single molecule with billion upon billions of smaller units chemically welded together to form a giant tangled network.The elasticity comes from the fact that the strands within the network are buckled like a concertina: pull on them and they straighten and elongate; let go and the buckles reappear.
But break a rubber (or most other solids), and the chemical welds - known as covalent bonds - are also broken.
These cannot be remade. Nor can a piece of rubber be remoulded or reshaped.
"We wanted to see if we could make a rubber-like material using small molecules," Dr Leibler of the Industrial Physics and Chemistry Higher Educational Institution (ESPCI) in Paris told the BBC's Science In Action programme.
The trick was to replace the covalent bonds in rubber with weaker connections known as hydrogen bonds.
These are like hands on neighbouring molecules that can clasp together, but let go when broken.
Dr Leibler quickly realised that this meant not only that the new rubber could be recycled and remoulded many times over, but that if separated by a cut or break, the chemical hands at the fresh surfaces would still be waving about ready to bind again.
We envision condom manufacturers are getting excited about potentially marketing self repairing prophylactics, among a myriad of other uses a material like this can be put to work in.
More at the BBC with video showing off the properties of the new material...
Press release: Supra-molecular chemistry yields new materials with outstanding properties
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