Self-Healing Plastic Skin

Stanford researchers has created the first synthetic material that is both self-healing at room temperature and sensitive to touch--a breakthrough that could be the beginnings of a new kind of robot skin.

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, they 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.

The researchers succeeded by combining two ingredients – the self-healing ability of a plastic polymer and the conductivity of a metal.

They started with a plastic consisting of long chains of molecules joined by hydrogen bonds – the relatively weak attractions between the positively charged region of one atom and the negatively charged region of the next.

“These dynamic bonds allow the material to self-heal,” said Chao Wang, a co-first author of the research. The molecules easily break apart, but then when they reconnect, the bonds reorganize themselves and restore the structure of the material after it gets damaged, he said. The result is a bendable material, which even at room temperature feels a bit like saltwater taffy left in the fridge.

The team’s goal is to make the material stretchy and transparent, so that it might be suitable for wrapping and overlaying on electronic devices or display screens.

[Stanford Engineering]