Graphene robot has some smooth moves

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Scientists have added a graphene layer to a polyethylene actuator to convert IR into energy to move the actuator

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The graphene robot can pick up a round object, move it and drop it into a container, all controlled by infrared light

A remote controlled graphene-based robot that picks up an object, moves it to a desired location and then drops it, has been developed by scientists in China. The robot could be used to perform surgery that is not easily done by hand.

Yi Xie at the University of Science and Technology of China, Hefei, and colleagues made the robot by combining an actuator, a device that converts energy into motion, with an electronic device, which responds to infrared light to curl and uncurl to pick up and drop objects.

’Integrating microelectronic devices with micromechanical devices represents an important step for developing intelligent electronics,’ says Xie. ’Transparent flexible electronics such as fold-out displays have received considerable attention, but integrating actuators with electronic devices requires excellent mechanical actuating behaviour and high transparency.’ So far, it has been difficult to find suitable transparent materials, adds Xie.

The team prepared the actuator by layering a polyethylene film onto a glass layer. On top of this, they added a graphene layer, which can absorb infrared light and convert this energy into heat with a high efficiency. The graphene - a sheet of carbon atoms one atom thick - also combines high transparency with strong mechanical performance. A strip of graphene on polyethylene that was 3mm by 12mm was then cut out and peeled off the glass, after which the strip curled up.

The team found that the strip uncurled in the presence of infrared light so switching the IR light on and off transformed the strip into a moving robot. The team demonstrated that their robot could pick up a small round object, move it and drop it into a container. They placed the uncurled strip above the object and turned the infrared light on, making the strip curl around the object. With the object in its grip, the strip was moved to a container, the infrared light was switched off, and the strip uncurled to drop its cargo.

’This is an elegant demonstration of photothermal energy conversion by graphene based actuators,’ says Jiaxing Huang, who studies graphene-based functional materials at Northwestern University in the US. ’It could inspire the design of transparent artificial muscles.’

Elinor Richards