Nanocar takes to the copper highway
12 Dec 2011 by Evoluted New Media
A four wheel drive car just 1 nm long which uses electrons as fuel has been developed by researchers at the University of Groningen, who hope it might find uses in nanometre-sized robotics or as tiny transporters to move molecules around. The vehicle has an organic carbon-based frame and four wheel or rotor parts connected to the body via carbon-carbon double bonds. It navigates its copper surface when a nearby scanning tunnelling microscope fires electrons at the bonds, causing them to break and reform the other way around – causing the wheels to turn and the car to move forward.
Scientists have previously made versions of the nanocar that they have moved across surfaces, but these have been mostly passive and need to be pushed or pulled in order to move in a certain direction.
Ben Feringa and his colleagues move their nanocar in two ways by adjusting the chirality of the rotor parts. In the first, the car moves along a random path, but the researchers can also make their car move in a nearly straight line.
“The important step taken, in my opinion, is that we have shown that we can propel a single molecule along a surface and control directionality,” said Feringa. “That is exactly what happens with protein nanomotors that ‘walk’ along filaments with control of directionality.
The car undergoes continuous and defined conformational changes upon sequential electronic and vibrational excitation. Scanning tunnelling microscopy confirms these conformational changes take place through inelastic electron tunnelling propelling the molecule unidirectionally across the copper surface.
The system can be adapted to follow a linear or random surface trajectory, or even remain stationary just by tuning the chirality of each of the four individual rotor units say the researchers.
The research – published in Nature – provides a starting point for exploration of more sophisticated molecular mechanical systems with directionally controlled motion.
Electrically driven directional motion of a four-wheeled molecule on a metal surface
