New magnetic ink to print devices that self heal in seconds!

Scientists, including one of Indian origin, have developed a magnetic ink that can be used to 3D print self-healing batteries, sensors and wearable, textile-based electrical circuits.

The researchers printed a self-healing circuit on the sleeve of a T-shirt and connected it with an LED light and a coin battery. They then cut the circuit and the fabric it was printed on.

At that point, the LED turned off. However, within a few seconds it started turning back on as the two sides of the circuit came together again and healed themselves, restoring conductivity.

The key ingredient for the ink is micro particles oriented in a certain configuration by a magnetic field.

Due to their orientation, particles on both sides of a tear are magnetically attracted to one another, causing a device printed with the ink to heal itself within seconds.

The devices repair tears as wide as 3 millimetres – a record 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, from University of California San Diego.

Existing self-healing materials require an external trigger to kick start the healing process. They also take anywhere between a few minutes to several days to work.

By contrast, the new system does not require any outside catalyst to work. Damage is repaired within about 50 milliseconds (0.05 seconds).

Engineers used the ink to print batteries, electrochemical sensors and wearable, textile-based electrical circuits.

They then set about damaging 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.

"We wanted to develop a smart system with impressive self-healing abilities with easy-to-find, inexpensive materials," said Amay Bandodkar, who earned his PhD in Wang's lab and is now a postdoctoral researcher at North Western University.

The study was published in the journal of Science Advances.