Scientists have developed a remarkable new molecular motor that spins when electricity passes through it. Inspired by an ancient invention, the tiny machine can even reverse its direction when the electrical voltage is switched. The achievement marks an important step toward creating working machines at the smallest possible scale.
Molecular machines are widely seen as a promising next frontier in miniaturization. Nature already provides examples inside living cells, where molecular motors use energy to produce movement. Researchers have spent decades trying to recreate these remarkable biological systems artificially, and progress in this field was recognized with the 2016 Nobel Prize in Chemistry.
An Ancient Invention Inspires a Molecular Motor Scientists first developed molecular motors powered directly by electricity in 2011. However, those earlier designs operated on surfaces and relied on the tip of a scanning tunneling microscope to drive their movement. The new motor takes a different approach, borrowing its basic design from the Archimedes screw, one of the oldest machines in recorded history.
Traditionally used to move water uphill, this simple device relies on a rotating spiral to transport material. Researchers adapted that principle to the molecular scale. Instead of moving water, their design allows electrons to travel through a spiral-shaped molecule, causing it to rotate as electrical current passes through.
A Tiny Molecular Screw Suspended Between Gold Tips The motor's central component is a specially designed spiral molecule created by the research group of Prof. Michael Pittelkow at the University of Copenhagen. Measuring only a few millionths of a millimeter, the molecule can attach to gold surfaces through sulfur atoms.
At the Weizmann Institute of Science in Israel, researchers led by Prof. Anil Kumar Singh positioned individual molecules between two gold tips sharpened to atomic dimensions. By carefully changing the separation between these electrodes, the team could stretch or compress the molecular screw.
Extract — continue reading at the source.
