This Newly Developed Magnetic Ink Can Print 'Self-Healing' Devices

Engineers from the University of California San Diego have developed a self-healing magnetic ink that can be used to make batteries, electrochemical sensors, and wearable, textile-based electrical circuits. The devices can repair tears as wide as three millimeters. This is a record in the field of self-healing systems.

Joseph Wang, director of the Center for Wearable Sensors and chair of the nanoengineering department at University of California San Diego, published his findings in an issue of Science Advances. "Our work holds considerable promise for widespread practical applications for long-lasting printed electronic devices," revealed Wang.

The key ingredient for the ink is microparticles oriented in a certain configuration by a magnetic field. Particles on both sides of a tear are magnetically attracted to one another, causing a device printed with the ink to heal itself. Existing self-healing technology requires an external trigger to commence the healing process and would take anywhere between a few minutes to several days to work. The system developed by Wang and colleagues doesn't require any outside catalyst to work and damage is repaired within about 50 milliseconds or 0.05 seconds.

Engineers damaged batteries, electrochemical sensors, and wearable, textile-based electrical circuits, cutting them and pulling them apart to create increasingly wide gaps. Damage was inflicted nine times at the same location and in four different places per device. With the magnetic ink, the devices still healed themselves and recovered their function while losing a minimum amount of conductivity.

When Wang and his team realized that the microparticles' magnetic fields canceled each other out in their natural configuration, diminishing their healing properties. Engineers solved this issue by printing the ink in the presence of an external magnetic field, which ensured that the particles oriented themselves to behave as a permanent magnet with two opposite poles at the end of each printed device. When the device is cut in half, the two pieces act as different magnets that attract each other and self-heal.

When asked about future plans, Wang and his team envision making different inks with various ingredients for a wide range of applications and developing computer simulations to test different self-healing ink recipes.