Self-healing plastic could mend robots on the go

US researchers have developed a self-healing polymeric material that could enable electronic systems and robots to mend themselves.

The team at the University of California in Riverside used a polar, stretchable polymer – polyvinylidene fluoride-co-hexafluoropropylene – with a mobile ionic salt. The polymer chains are linked by forces generated between water molecules and sodium ions.

The resulting material can stretch up to 50 times its usual size (see image). After being torn in half, the material automatically stitches itself back together completely – within one day.

For the next step, the researchers are working on self-healing materials that are tolerant to harsh conditions, such as high humidity and high temperature.

Combining mechanical performances and electronic properties in one material has been challenging, says Chao Wang, a chemist at the university and the lead author. “Eventually we will have to sacrifice either of the properties to make the materials work for one specific application.”

Self-healing polymer materials for the consumer market are potentially very attractive, especially if they restore mechanical integrity while maintaining the multifunctional performance of the system.

“In the longer term, I envisage future materials that respond in a more complex way to mechanical failure or physical deterioration – such as structures that are ‘truly regenerative’ and renew themselves over their lifetimes in much the same way that bones do,” says Richard Trask, advanced materials expert at the University of Bath, who didn’t take part in the study.

Wang expects the material to be available in stores in the next three-to-five years.