A self-healing rubber that binds together after being punctured could pave the way for advanced surgical and wash-up gloves, self-healing shoes, and more. “You can feel the material mending itself when you hold the fractured sides together,” says inventor Ludwik Leibler. The substance self-heals when its surfaces are brought together under gentle pressure at room temperature. After the material fixes itself, it is as strong as before, says Leibler, a polymer chemist at the Industrial Physics and Chemistry Higher Educational Institution in Paris.

Common rubber is strengthened by long polymer chains that are crosslinked or coupled, usually by covalent, ionic, and hydrogen bonds. But only hydrogen bonds can be remade once a material is fractured, and normally there are not enough hydrogen bonds to let rubber fix itself.

Leibler's team solved the problem by getting rid of ionic and covalent bonds. To do so, they developed a transparent, yellow rubber which crosslinks only with hydrogen bonds. Leibler's team synthesized the material from cheap and renewable fatty acids and urea. One drawback: Without covalent and ionic bonds, the material is weaker than conventional rubber.