Wednesday, September 07, 2011
World's Smallest Electric Motor
New Scientist reports: [edited]
For the first time, an electric motor has been made from a single molecule. At 1 nanometre long, that makes the organic compound the smallest electric motor ever.
E. Charles Sykes at Tufts University in Boston and colleagues used asymmetric butyl methyl sulphide, a sulphur atom with a chain of four carbons on one side and a lone carbon atom on the other. They anchored the molecule to a copper surface via the sulphur atom, producing a lopsided, horizontal "propeller" that is free to rotate about the vertical copper-sulphur bond (see diagram).
Above the molecule they placed a metal needle a few atoms wide at its tip. When they flowed a current from this tip, through the molecule, to the conductive copper below, the molecule converted the electrical energy into rotational energy. It bounced around in jittery hops about 50 times a second.
Sykes hopes to harness his tiny motor to fight the friction that slows fluid flow in nano-sized tubes.