The material, called Electronic Skin, mimics the natural functions of human skin in terms of strength, elasticity, and sensitivity, and can be used to collect biological data in real-time. Electronic skin, or e-skin, can play an important role in next-generation prosthetics, personalized medicine, soft robotics, and artificial intelligence.
“The ideal e-skin mimics many of human skin’s natural functions, such as temperature recognition and touch, safely and in real-time,” said KAUST postdoctoral Yichen Cai. Creating the right flexible electronics that is capable of such dangerous tasks while suffering from bumps and scratches in everyday life is a challenge and any material used must be carefully manufactured.
Most e-skins are made by applying an active nanomaterial (sensor) to a flexible surface that adheres to human skin. However, the bond between these layers is often very weak, which reduces the strength and sensitivity of the material; On the other hand, if it is too loud, flexibility may be limited, so the circuit is more likely to break and break.
“The landscape of leather electronics is constantly moving at an incredible pace,” Cai said. “The advent of 2D sensors has accelerated efforts to integrate these atomically thin, mechanically strong materials into functional, durable artificial leather.”
The team, led by Cai and colleague Jie Shen, has now created a durable e-skin with hydrogel-reinforced silica nanoparticles as a solid and flexible substrate and MXene 2D titanium carbide as a sensing layer combined with highly conductive nanowires.
“Hydrogels are more than 70 percent water, so they are very suitable for human skin tissues,” explains Shen. By stretching the hydrogel in all directions, modifying the nanowire layer, and carefully controlling the release, the scientists created conductive pathways to the sensor layer that remained intact, even as the material was extended to 28 times its original size. Its e-skin prototype can detect objects at a distance of 20 centimeters, respond to stimuli in less than a tenth of a second, and when used as a pressure sensor, recognizes the handwriting with which it is written. It works very well even after 5,000 deformations and repairs approximately a quarter of a second at a time. “This is a remarkable achievement for e-skin, which will continue to harden after repeated use,” says Shen, “which mimics the elasticity and rapid healing of human skin.”
This type of e-skin can control various biological information, such as changes in blood pressure, which can be detected by vibrations in the nerves, and movements of large arms and joints. This data can be shared and stored in the cloud via Wi-Fi.
“One remaining obstacle to the widespread use of e-skins is the proliferation of high-resolution sensors,” added Vincent Tung, group leader; “Lars-assisted additive production, however, offers new promise.”
“We see the future of this technology outside of biology,” Cai added. “An innovative sensor tape could one day monitor the structural health of inanimate objects such as furniture and aircraft.”
