New plastic self-heals when exposed to light

Nature : A new kind of self-repairing plastic has been developed by Christoph Weder, of the University of Fribourg in Switzerland, and colleagues. Unlike other self-repairing materials, which are heated until they melt and then allowed to cool and reharden, the new material requires only exposure to ordinary light. The rubbery material consists of small chains of polymers interspersed with metal ions. When light hits the material, the metal heats up, causing the polymer chains to break apart and flow into cracks in the damaged area. When the light is turned off, the molecules reassemble themselves and thus repair the fracture. Currently, the plastic must be thin enough that light can penetrate it, but it’s possible that fiber-optic cables could be incorporated to provide light throughout the material. The new plastic could extend the lifetime and improve the durability of myriad polymer-based products and could also be used in varnish and paint. The team’s results were published online yesterday in Nature .