Human skin needs to be flexible and able to repair itself. It’s also sensitive to touch and pressure, and since both are measured as electrical signals, skin needs to conduct electricity.
For a synthetic version, scientists have designed a new flexible, electrically conductive polymer that can heal its own cuts and tears. ScienceNOW reports.
‘Epidermal electronics’ is the production of thin and flexible circuits that can be attached to the skin (as electronic skin and wearable heart rate monitors, for example) or provide skin-like sensitivity to prosthetics.
Existing self-healing polymers aren’t much use in electrical sensors. So to increase the conductivity, a team led by Stanford’s Zhenan Bao incorporated nickel atoms that allowed electrons to jump between the metal atoms.
The polymer is sensitive to applied forces like pressure and torsion (twisting) because such forces alter the distance between the nickel atoms, affecting the difficulty the electrons have jumping from one to the other and changing the electrical resistance of the polymer.
When the researchers cut the polymer (pictured) through with a scalpel and then pressed the cut edges together for 15 seconds… the sample regained 98 percent of its original conductivity, demonstrating how it can be cut and healed repeatedly.
This is the first time anyone’s shown this combination of both mechanical and electrical self-healing. The next step would be to make it stretchable like human skin.
The work was published in Nature Nanotechnology this week.
Image from B. C-K. Tee et al., Nature Nanotechnology