Scientists have developed a transparent, self-healing, highly stretchable conductive material that can be electrically activated to power artificial muscles and used to improve batteries, electronic devices and robots.
The end product is a soft, rubber-like material that is easy to produce at low cost. It can stretch to 50 times its original length, and can heal itself from a scissor cut in the space of 24 hours at room temperature. And just 5 minutes after being cut, the material can stretch to two times its original length again.
A researcher team from the University of California, Riverside and the University of Colorado, in a study published Friday in the journal Advanced materials, described that the material is also an ionic conductor, capable of conducting electricity through the flow of ions – and this is the first time scientists have combined self-healing properties in an ionic conductor.
“Inspired by wound healing in nature, self-healing materials repair damage caused by wear and extend the lifetime, and lower the cost, of materials and devices,” the University of California, Riverside, whose researchers were involved in the study, said in a statement.
The material could give robots the ability to self-heal after mechanical failure, extend the lifetime of lithium ion batteries used in electronics and electric cars and improve biosensors used in the medical field and environmental monitoring.
“The key difficulty is the identification of bonds that are stable and reversible under electrochemical conditions. Conventionally, self-healing polymers make use of non-covalent bonds, which creates a problem because those bonds are affected by electrochemical reactions that degrade the performance of the materials.”
In order to overcome this hurdle, the researchers used what’s known as ion-dipole force, an attractive force that is created due to interaction between an ion and a neutral molecule containing a dipole. Doing so enabled the researchers to create a material that had the properties they were seeking.
“Creating a material with all these properties has been a puzzle for years,” study co-author Chao Wang from the University of California said in the statement. “We did that and now are just beginning to explore the applications.”
Wang said his love for Wolverine helped inspire his interest in self-healing materials, which mimic materials seen in Nature and can help extend the lifetime and lower the cost of man-made materials and devices.
The researchers demonstrated how the material could be used as an artificial muscle that contracts and expands in response to external stimulus.
“Most importantly, the researchers were able to demonstrate that the ability of the new material to self-heal can be used to mimic a preeminent survival feature of nature: wound-healing,” the university said in the statement. “After parts of the artificial muscle were cut into two separate pieces, the material healed without relying on external stimuli, and the artificial muscle returned to the same level of performance as before being cut.”
It’s still early days for the material, but its unique combination of properties could make next generation electronic devices and robots more resilient than ever.