CHINA – Researchers have made an intelligent skin that is, via frictional contact, it self-powers itself with the objects it touches. This discovery might have applications in robots, bionics and artificial intelligence.

For example, when a bee crawls through intelligent skin, the skin not only detects the insect, but also uses impulsive triboelectric charge that accumulates between the bee and the smart skin to enhance its detection capability, which eliminates the need for batteries.

The research group, led by Zhang Haixia at Peking University, has published the work on the novel smart skin in a latest issue of ACS Nano.

Zhang said that any electronic or smart skin needs a power supply hence this is a serious problem. It is inconvenient for users to make an intelligent and flexible thin skin which  has a large and heavy battery. Therefore their innovation essentially addresses this problem.

As the scientists explain, the triboelectric charge occurs anywhere where two objects are touching each other, even though these charges are so small that often are overlooked.

He said to picture a scenario where walking to a table to get a cup of coffee. Opposite charges generated on the surface between the shoe and the ground. At the time of collecting drinking cup opposite charges produced between the palm of the hand and the handle of the cup. On the other hand, when one swallows coffee, charges produced between the surface of their digestive tract and coffee. These are all impulsive, but often overlooked charges to make our skin are completely self – powered.

This method of self-feeding is feasible since the smart skin utilizes very little power. Earlier developed smart skins are digital where the sensitivity of its resolution is determined by a grid of pixels. The resolution enhancement generally requires increasing the number of pixels and electrodes. By contrast, the new smart skin using an analogous method requires only four electrodes.

Electrodes are placed in four opposite ends of the skin smart. When an object like a finger applies pressure on a smart skin, a current is produced through the skin induces a voltage on each electrode. The voltage at each electrode varies as the distance between the applied force and each electrode changes. Therefore, the location of the applied force can be determined from relative voltages.

According to Zhang, the use of both the spontaneous triboelectric charges and the flat electrostatic induction detects the contact applied to the smart skin. The triboelectric charges take place all over the place in our everyday in our lives when two surfaces contact each other and when a charged surface draw nears a metal block (or electrode), opposite charges are induced, which is the effect of electrostatic induction. The effect of intensity electrostatic induction relies on the distance between the charged surface and the metal.

The group’s experiments revealed that the analog smart skin can determine the location of a force applied with an average resolution of 1.9 mm when wrapped around a robotic hand. To exhibit the high sensitivity of the smart skin to very small forces, they showed that smart skin can sense the presence of a honey bee (0.16 grams) and grasshoppers.

Their future work is to enhance the smart skin properties in terms of resolution and detection sensitivity, which can be directed at a low cost, as these further developments do not necessitate any additional electrodes. They also plan to develop intelligent ways to protect skin from environmental interference and other electronic components, which might be a concern during integration into mobile phones.

Source: Phys.org