Self-Healing Electronic Skin

Zhenan Bao and her team of researchers at Stanford University are striving to create electronic skin that can both register touch and heal itself the way natural skin can. Many materials scientist have worked on created flexible circuits while chemists have tackled the problem of self-healing polymers. Yet despite all the effort, no material has be discovered or created that can combine these two attractive properties. This is a big problem for prosthetics as many of these devices do not have a sense of touch, which makes many of its users complain about the clumsiness and clunkiness of current devices.  

Last year Bao's team was able to solve half of the puzzle, creating a flexible electronic skin that can sense pressure (video below), and this November, the team announced that they have come one step closer to a self-healing polymer.

In a paper published in Nature, Bao showcases her recent breakthrough regarding a self-healing electronic skin. By incorporating nickel atoms into a self-healing polymer, the Stanford team was able to arrive at a material that achieves both of the qualities needed for a self-healing electronic skin. The polymer is able to gain the electrical properties because through forces like pressure or twisting, the distance between adjacent nickel atoms changes. This affects how easily electrons can move from atom to atom, which changes the electronic resistance of the material. 

To demonstrate the effectiveness of the healing properties of the material, the researchers cut the material with a scalpel  They then help the two pieces together at the edges and after 15 seconds, electrical conductivity was restored with about 90% efficiency, and after a mere 10 minutes, the break was fully repaired and the material was once again flexible. 

John Boland of the Center for Research on Adaptive Nanostructures and Nanodevices (CRANN) at Trinity College Dublin called the development a breakthrough in an article on ScienceNOW, though he notes that scalpel cuts are very neat and the tearing and stretching of the material may affect its self-healing properties.