Researchers Create Self-Healing Sweat Sensor, Capable of Repairing Cut Threads in Under 30 Seconds

Researchers from Kangwon National University, Pukyong National University, the University of Science and Technology, Korea Research Institute of Chemical Technology (KRICT), Korea Advanced Institute of Science and Technology, and National Nanofab Centre have published a paper detailing the creation of a headband designed to analyze sweat — and to heal itself when cut, scratched, or otherwise damaged during exercise.

"Sensors with autonomous self-healing properties offer enhanced durability, reliability, and stability," the abstract to the team's research paper begins. "Although numerous self-healing polymers have been attempted, achieving sensors with fast and reversible recovery under ambient conditions with high mechanical toughness remains challenging. Here, a highly sensitive wearable sensor made of a robust bio-based supramolecular polymer that is capable of self-healing via hydrogen bonding is presented."

The headband itself is designed to analyze electrolyte levels in sweat during exercise, something that has been attempted before using a range of sensor types that all have one major drawback: They can be displaced or damaged during exercise, and if damaged are irreparable. The team's alternative, by contrast, is capable of repairing damage — rated at a 97 percent self-healing efficiency after 30 seconds at room temperature.

The healing process works through hydrogen bonding in a citric acid-based polymer which coats the carbon fibre thread electrodes of the sensor itself and which are responsible for measuring the potassium and sodium ions in the sweat. During the test process, in which a human test subject wore the headband while cycling on a stationary bike for nearly an hour, the researchers cut the threads with scissors — and found they returned to normal operation in just 20 seconds.

The team's paper has been published in the journal ACS Applied Materials and Interfaces.