Researchers at Stanford have created a synthetic material that is sensitive to touch and capable of healing itself after being torn or cut. A paper published yesterday in the journal Nature Nanotechnology describes how chemical engineering professor Zhenan Bao, PhD, and her team combined the self-repairing ability of a plastic polymer and the conductivity properties of a metal to develop the new material, which could lead to more advanced prosthetics.
A Stanford Report story discusses how Bao and her group tested their new product’s mechanical strength:
The researchers took a thin strip of the material and cut it in half with a scalpel. After gently pressing the pieces together for a few seconds, the researchers found the material gained back 75 percent of its original strength and electrical conductivity. The material was restored close to 100 percent in about 30 minutes. “Even human skin takes days to heal. So I think this is quite cool,” [Benjamin Chee-Keong Tee], a researcher on the projectsaid.
What’s more, the same sample could be cut repeatedly in the same place. After 50 cuts and repairs, a sample withstood bending and stretching just like the original.
The composite nature of the material created a new engineering challenge for the team. Bao and her co-authors found that although nickel was key to making the material strong and conductive, it also got in the way of the healing process by preventing the hydrogen bonds from reconnecting as well as they should.
For future generations of the material, Bao said, the team might adjust the size and shape of the nanoparticles, or even the chemical properties of the polymer, to get around this trade-off.
Previously: Beetle wing design inspires ultra-sensitive electronic skin, Stanford researchers develop transparent, stretchable skin-like sensor and Stretchable solar cells could power electronic ‘super skin’
Photo by L.A. Cicero