Scientists in China have developed a novel material they say could improve the performance of prosthetic devices and robotics, by allowing them to sense injuries just like people. The artificial skin uses a special gel that changes color in response to force, mimicking the bruising process to offer a visual sign that damage has taken place.
Scientists see artificial skins loaded with electronics and different types of sensors as a way of enhancing the performance of robots and prosthetics, by bringing their behavior closer to that of humans. We've seen examples that change color in response to force, take inspiration from snakes to sense heat and simulate a sense of touch through the use of pumped air.
The authors of the new study took a slightly different route to most, in that they sought to use ionically conductive materials for their technology, rather than electrical conductors that aren't always compatible with the human body.
This led to the development of what they call an ionic organohydrogel, which is loaded with a molecule called spiropyran that goes from pale yellow to blue-ish purple when subjected to mechanical stress, a little like human skin. This formed the basis of what the team calls an I-skin, which was taped to different body parts of volunteers including fingers, hands and knees, and put to the test.
Through these experiments, the scientists showed that their I-skin could be bent and stretched without "bruising," though this did affect its electrical signals. Forceful and repeated pressing, hitting and pinching did change its color, however, with the purple remaining for between two to five hours before the I-skin reverted back to its original color.
It is still early days, but the research offers an interesting example of how an artificial skin or similar material could be applied to the surface of a prosthesis, robots or even wearable devices and reveal when it has taken mechanical damage that warrants attention.
The research was published in the journal ACS Applied Materials & Interfaces.
Source: American Chemical Society