Electronic skin can self-heal after a cut, researchers find

Soft electronics and robotic devices could, like human skin, recover autonomously from damage with a new design made by Stanford scientists.

In its latest study, a research team described how they combined two dynamic polymers to achieve autonomous realignment in multilayered soft electronics. This could help devices recover from various forms of damage such as being hit by something or dropped to the ground. 

Usually, these devices are multilayered and embedded with conductive or dielectric materials to achieve functional properties while also maintaining the soft mechanical properties of the self-healing polymer matrix.

Moreover, self-healing devices often require manual realignment of individual layers after damage to properly align different functional components within the polymer, as even slightly misaligned layers can limit the functional recovery of a device. 

For these reasons, autonomous self-healing robots have been extremely difficult to design. 

However, Christopher Cooper and colleagues at Stanford have been able to achieve this feat by combining two orthogonal self-healing polymers with identical dynamic hydrogen-bonding interactions but with immiscible polymer backbones.

The researchers relied on composition gradients between the two polymers to enable interlayer adhesion between the layers while enabling self-recognition and healing of different functional layers.

To test the design, the authors fabricated thin-film devices with conductive, dielectric, and magnetic particles and demonstrate their ability to functionally self-heal after mechanical damage to 96 per cent of their initial capacitance.

The test not only succeeded but also showed that the approach could be used to magnetically guide the self-assembly of soft robots and underwater circuits.

Other researchers have also been looking into designing electronic devices that can sense surfaces or attend to their own injuries, like human skin. 

In March, a team at Pohang University of Science and Technology (Postech) and the University of Ulsan in South Korea, was inspired by the qualities of crocodile skin to develop a new type of stretchable pressure sensors, which can detect various types of touch and pressure.

In December, Cornell University engineers created a soft robot capable of detecting when and where it was damaged and healing itself on the spot.

The findings of the research have been published in the journal Materials Science.