Artist concept: The molecular "car" on a "road" of copper atoms
Small cars may eventually be all there’s room for on the streets of congested cities, but nothing quite compares to a new four-wheeled molecular-sized car developed by European researchers.
The BBC reports of a nano-sized molecule which has four branches that act as wheels. By applying a small current–less than a volt–with the tip of a scanning tunneling microscope (STM), researchers at University of Twente (the Netherlands) made the wheels rotate. With 10 electric bursts, the car traveled six billionths of a meter.
The microscope serves as the “batteries” of the tiny car by way of supplying electrons that jump off the atom-sized tip to the molecule. The “engine” of the approach lies with the car’s “wheels” or molecular rotors that undergo a change in shape when they absorb the electrons. The structural change creates rotary motion, which in turn, inches the car forward.
As the chemical groups in each "wheel" change shape, the car inches ahead
The approach, published in Nature, joins recent efforts to build molecular vehicles, but the researchers note that other designs differ in that they’ve used passive rollers.
Tibor Kudernac, a chemist at the University of Twente, the Netherlands, and lead author of the paper said that the research showcases how to build up from single, designed molecules, or “bottom-up” nanotechnology.
“A wide array of machines has been demonstrated in recent years, incorporating parts etched to minuscule sizes from chunks of metals or semiconductors - a small version of traditional, “top-down” manufacturing,” notes the BBC article.
While applications for molecular machines are still far off, the work can lead to sophisticated nano-scale systems with directionally controlled motion.
(Sources: BBC, Scientific American)
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