The body’s largest organ, the skin, plays a key role in facilitating our sense of touch, but its sensitivity is hard to replicate in artificial versions. Now, researchers have developed a new type of electronic skin (e-skin) containing tiny embedded hairs that can precisely perceive touch and the direction it moves.
E-skins are thin films of material with electronic properties that allow them to perform some of the functions of natural human skin, such as registering touch, pressure, temperature or even pain. These artificial skins could be useful for patients needing grafts after major injury, or to give a more advanced sense of touch to prosthetic limbs and robots.
In the new study, researchers from Chemnitz University of Technology and Leibniz IFW Dresden developed an e-skin containing a new type of sensor that makes it extra sensitive to touch. The breakthrough comes from mimicking an important but overlooked factor in the human sensation of touch – tiny hairs lining the skin.
The scientists embedded tiny, magnetic hairs into an elastomeric material to make their e-skin. Like natural hairs, these artificial ones have bulbous roots that sit below the surface of the e-skin and move around when the hair above is touched. Each of these roots is surrounded by a 3D magnetic sensor, allowing the exact position of the root to be tracked in real-time. That allows the entire matrix of sensors to register that a hair has not only been touched, but the direction of that touch across the e-skin.
The team says these magnetic sensors can be fabricated in bulk sheets fairly easily. They can then self-fold into 3D boxes to house the hair roots, through a process known as micro-origami.
"Our approach allows a precise spatial arrangement of functional sensor elements in 3D that can be mass-produced in a parallel manufacturing process,” said Christian Becker, first author of the study. “Such sensor systems are extremely difficult to generate by established microelectronic fabrication methods.”
The research was published in the journal Nature Communications.