In a paper published Wednesday in the journal Science Advances, Dr. Joseph Wang and other researchers from the nanoengineering lab at the University of California, San Diego, show how ink that includes magnetic particles can be used to print materials for self-healing “smart” garments. Smart garments such as sportswear that can monitor a workout, or clothing for newborns to track vital signs, have so far been limited by the high price and rigidity of their components. One way around these problems is to print cheaper components, such as wearable batteries, sensors, and circuits, using electrically functional inks. Until now, the fragility of these electronic components was the one thing standing in the way of making such garments practical, flexible, and affordable.
Dr. Wang’s research shows how the use of ink that includes magnetic particles could be used to create self-healing fabric and devices. As soon as one of these garments or components breaks, the magnetic particles attract each other and heal the break. In Wednesday’s paper, Dr. Wang and his team show how their self-healing ink can repair cuts of up to three millimeters long, in only 50 milliseconds.
Existing smart clothes and smart garments, such as clothes that monitor health information during exercise, usually feature sensors that are attached to the clothing’s fabric. These sensors are expensive and breakable.
Amay Bandodkar, one author of the study, explained “We wanted to make wearable devices that were more skinlike. Just like the human skin is stretchable and self-healing, we wanted to impart a self-healing ability to printed electronics.”
The team’s self-healing ink consists of ground neodymium magnets, which are often found in hard drives.
“We basically just pulverized these magnets into microscopic particles and incorporated them into the ink,” Dr. Bandokar explained.
Previous attempts to create self-healing fabrics and other materials have taken advantage of polymerization, a chemical reaction that uses chemical bonds to heal broken fragments. However, this method is limited by the need for externally applied heat, an inability to mend large tears, and this method can take hours or days to heal material fully. The new method is much simpler, faster, and does not require external inputs like heat. They would also be cheap to produce – Dr. Bandokar estimated that ten dollars of ink could produce hundreds of small, self-healing devices.
He added that it may take years to assess the best ratios for ink ingredients for different applications, which Bandokar thinks could someday include solar panels, and medical implants, in addition to self-healing garments.