A new magnetic ink has been developed that will be capable of being used to create self-healing batteries, electrochemical sensors and wearable, textile-based electrical circuits. The ink has already shown to repair more damage and at a quicker speed than current self-healing systems.
Developed by a team of engineers at the University of California San Diego, the ink’s key ingredient is microparticles that are oriented in a certain configuration by a magnetic field.
Because of the orientation of these particles, any tear in a device printed with the ink will self-heal as particles on both sides of the tear are magnetically attracted to one another.
The ink has already set records by repairing tears as wide as 3mm, a new high in the field of self-healing systems.
“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.
In addition to the extent of damage the ink allows devices to repair, it is also notable for its ability to do so without any outside catalyst.
Existing systems require external triggers to begin the healing process, and can take anywhere between a few minutes to several days to do so. By contrast, the new system requires no external trigger and repairs damage within roughly 50 milliseconds.
The engineers tested their system by printing batteries, electrochemical sensors and wearable, textile-based electrical circuits that they then set about damaging by cutting them and pulling them apart to create increasingly wide gaps. The devices were damaged nine times at the same location, as well as having damage inflicted in four different places on the same device.
Despite the extensive and repeated damage, the devices continued to heal themselves and recover function, losing only a minimal amount of conductivity.
For example, a self-healing circuit was printed on the sleeve of a T-shirt and connected to an LED light and a coin battery. The circuit and the fabric it was printed on were then cut, resulting in the LED turning off. Within a few seconds, however, it started turning back on as the two sides of the circuit came together and healed.
“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 engineers envision that, in the future, they will be able to expand the range of applications for the ink by making use of different variations with different ingredients.
Additionally, they plan to test different self-healing ink recipes in silicon through computer simulations, before taking them for lab testing.