New magnetic ink can make self-healing wearables

A team of engineers at the University of California (UC) San Diego has developed a magnetic ink that can be used to make self-healing wearables and textile-based electrical circuits. The ink can repair tears as wide as 3 millimeters, a record in the field of self-healing systems, in about 0.05 seconds and does not require any outside catalyst to work.

The key ingredient for the ink is microparticles oriented in a certain configuration by a magnetic field. Because of the way they are oriented, particles on both sides of a tear are magnetically attracted to one another, causing a device printed with the ink to heal itself.

“Our work holds considerable promise for widespread practical applications for long-lasting printed electronic devices,” said Joseph Wang, director of the center for wearable sensors and chair of the nanoengineering department at UC San Diego.

Engineers used the ink to print various devices including wearable and textile-based electrical circuits. They then damaged these devices by cutting them and pulling them apart to create increasingly wide gaps. Researchers repeatedly damaged the devices nine times at the same location. They also inflicted damage in four different places on the same device. The devices still healed themselves and recovered their function while losing a minimum amount of conductivity.

The nanoengineers also printed a self-healing circuit on the sleeve of a T-shirt and connected it with an LED light and a coin battery. The researchers then cut the circuit and the fabric it was printed on. At that point, the LED turned off. But then within a few seconds it started turning back on as the two sides of the circuit came together again and healed themselves, restoring conductivity.

“We wanted to develop a smart system with impressive self-healing abilities with easy-to-find, inexpensive materials,” said Amay Bandodkar, one of the papers' first authors, who earned his Ph.D. in Wang’s lab and is now a postdoctoral researcher at Northwestern University.

The paper called ‘All-printed magnetically self-healing electrochemical devices’ was published in Science Advances. Engineers who worked with Bandodkar and Wang on this research include Christian S. Lopez, Allibai Mohanan, Vinu Mohan, Lu Yin and Rajan Kumar from the Department of nanoengineering at the Jacobs School of Engineering at UC San Diego.

The research was supported by the NIH and Advanced Research Projects Agency-Energy.