Researchers Li-Heng Cai from the Harvard, Jinrong Wu from the Sichuan University, China, and David A. Weitz from Mallinckrodt have, in collaboration, developed a rubber that heals itself. The study that was published in the journal Advanced Materials states that the hybrid rubber developed by these Harvard researchers has both reversible and covalent bonds, enriching the rubber with the capability of repairing itself.
While a variety of self-healing materials are already available across the globe, rubbers capable of repairing themselves are a new. The task of developing this variety of rubber has been difficult, mostly owing to the fact that rubber is made from polymers that are connected to each other by permanent covalent bonds. As the bonds are strong, they do not reconnect after they are broken once. The researchers overcame this issue by making the interconnecting bonds reversible so the material can reform after it is broken.
For mixing the reversible and covalent bonds, the researchers developed randomly branched polymers that connected these types of bonds together. The randomly branched polymers allowed for the two bonds, previously known as unmixable, to homogenously mix on a molecular level. This process led to the development of the self-healing rubber.
Unlike conventional rubber, the self-repairing rubber thus discovered, redistributes stress, which mitigates the formation of a localized trauma point and does not lead to cracking. After the stress is releases, the material goes back to its original form and the cracks are repaired on their own. Harvard’s Technology Development office has filed for a patent for the technology and is also looking for opportunities to commercialize the rubber. This means that the material will be seen in markets very soon.