A rubber tree has inspired researchers to develop a class of self-healing elastomers that can repair themselves autonomously. Researchers at the Fraunhofer Institute for Environmental, Safety and Energy Technology (UMSICHT; Oberhausen, Germany) loaded microcapsules with a one-component adhesive of polyisobutylene and placed it inside elastomers made from synthetic rubber. The result is plastics that stop the growth of microcracks that can propagate and lead to spontaneous material failure.
In the rubber tree and other plants that produce latex, such as the Weeping Benjamin, the latex contains capsules filled with the protein hevein. If the tree is damaged, latex is emitted and the capsules break open to release the protein, which acts to bond the latex and heal the wound.
Fraunhofer researcher Anke Nellesen said that in the polymer version they produced, if pressure is put on the capsules, they break open and separate this viscous material, which then mixes with the elastomers' polymer chains and closes the cracks....