New 3D printed rubber material can repair itself with no outside help

It would certainly be great if the sole of your shoe broke if it could fix itself. What if your tires could repair themselves if punctured while you kept on driving? Researchers at the University of Southern California Viterbi School of Engineering have developed new 3D rubber material that could make those self-repairing items a reality.

Assistant Professor Qiming Wang and several students along with an assistant professor from another university have teamed up to make a new material that can be manufactured quickly and can repair itself if it is fractured or punctured. The team believes that the material could be game-changing for shoes, tires, soft robotics, and possibly electronics.

The material is made using a 3D printing method that uses photopolymerization. That means the process uses light to solidify a liquid resin into the shape needed. For the self-healing properties, the team had to work on the chemistry of the material using a chemical group called thiols.

When an oxidizer was added, thiols are able to transform into a new group of materials called disulfides. The team had to find the perfect ratio between the two groups for their invention. As the oxidant was increased, self-healing was improved, but the photopolymerization behavior was weaker. The trick was finding the perfect ratio to get high-self-healing and rapid photopolymerization.

The team says that in five seconds they can print 17.5 mm square and complete an entire object in about 20 minutes. The material can repair itself in a few hours. The team is working on developing other self-healing materials including rigid plastics. The material could one day be used for car parts, composite materials, or body armor.