A group of French researchers announced today that they'd invented a new form of rubber that "heals" when cut in half. Made of rubber and a component in urine, the rubber represents the gold standard for new synthetics made via molecular engineering. Molecules in the rubber are so strongly attracted to each other that they rebond when cut — no glue required.
The researchers say they're already making mass quantities in the lab. BBC News reports on a first-hand look at the rubber:
Using a razor blade he severed a thin strand of the yellowish material (the colour of corn oil), showed me the clean square faces, and then pressed them together. Almost immediately, the grip was strong enough for him to hold the sample just at one end.
Within an hour the bonds had rebuilt themselves so thoroughly that it was possible to stretch the strand to twice its length without any sign of weakness where the cut had been made. One obvious use, says Dr Leibler, is for self-healing seals. Puncture a seal in a compression joint with a nail, and the hole would automatically repair itself.
The researchers also suggest it would be a terrific component of children's toys. Self-healing rubber [BBC]