The carpenter’s adage “Measure three times, cut once” may not apply with devices made from a new composite material developed at Carnegie Mellon University. We’ve written about self-healing properties before, such as the work at the Cockrell School of Engineering at The University of Texas at Austin on a self-healing conductive gel. Among other applications, we also wrote about Fudan University’s work with self-healing batteries and self-healing soft robots at the Vrije Universiteit Brussel (VUB).

A team of Carnegie Mellon researchers from the Human-Computer Interaction Institute (HCII) and the Department of Materials Science and Engineering (MSE) developed the self-healing composite. The group recently demonstrated the material’s self-healing properties with a variety of sensors and actuators. After being cut, ends of the material reconnected and the joining seam eventually disappeared, even when the pieces were put back in different configurations from the original.

The CMU material is a combination of polyborosiloxane (PBS) and multiwalled carbon nanotubes (MWCNTs). The nanotubes enable conductivity and the PBS polymer brings the self-healing quality. The material remains functional when it is cut, which suggests to the CMU researchers they may be able to build sensors and other electronic devices from modules as needed, similar to using LEGO pieces.  Lining Yao, assistant professor in the HCII, said it also may be possible to design standard sheets or forms than can be cut into various shapes depending on the desired use.

Yao also said that while they can reconfigure the material, at present they cannot re-wire it. Future designs with redundant circuits may enable further customization including re-wiring. CMU’s demonstration pieces with the self-healing material included a reusable arm cast that molds around a broken arm, and a soft controller that responds to touch.

A material such as this could make wearable devices both flexible and rugged, which could open up a new range of applications for health and medical tasks.