X-Men's Wolverine can heal from wounds and injury almost instantly and this special ability has inspired researchers to develop a self-healing material.

The transparent material is highly stretchable, able to extend to 50 times its original length and can conduct electricity. It can also heal itself from a scissor's cut within 24 hours at room temperature.

Ionic Conductor With Self-Healing Properties

It is the first time researchers have created an ionic conductor, a material that can conduct electricity through the flow of ions, with self-healing properties.

Researchers have been able to develop stretchable and transparent ionic conductors before but adding self-healing properties was challenging because this requires non-covalent bonds between individual molecules that do not share electrons. Passing electricity through the bonds also degrades them.

To solve these problems, Chao Wang, from the University of California, Riverside, and colleagues used ion-dipole interactions to hold the molecules together. This combines the charged ions with polar molecules where each end of the molecules is oppositely charged.

The small electrical imbalance in these molecules produces an electrostatic attraction between them so by combining a stretchable polar polymer and high-ionic strength salt, the researchers were able to give the material the properties they need.

"Here, a transparent, self-healing, highly stretchable ionic conductor is presented that autonomously heals after experiencing severe mechanical damage. The design of this self-healing polymer uses ion-dipole interactions as the dynamic motif," researchers reported in their study, which was published in the journal Advanced Materials on Dec. 23.

Wang and colleagues placed a transparent membrane in between two layers of the new material to produce an artificial muscle prototype. This artificial muscle is activated by electrical signals in the same manner human muscles move in response to brain signals.

Potential Applications

Self-healing technology has crucial uses in certain fields such as in space travel. The self-repairing property of the material, its stretchability and electrically conductivity make it ideal for improving the qualities of power sources and machineries.

The material, for instance, can give robots the ability to self heal after a mechanical failure and stretch the lifetime of lithium ion batteries that are used in electric cars and electronics.

It may even be used to produce artificial muscles that are stronger and more flexible compared with metal limbs, as well as improve biosensors that are used in environmental monitoring and the medical field.

"Creating a material with all these properties has been a puzzle for years," said Wang. "We did that and now are just beginning to explore the applications."