The [2] rotaxane molecules each contain a ring around the «handle» of the barbell. (scientificamerican.com)
To make their device, the team laid down a tightly packed series of 400 parallel silicon wires (separated by just 33 nanometers) and coated them with a layer of barbell - shaped [2] rotaxane molecules. (scientificamerican.com)
Organic chemist David Leigh of the University of Edinburgh, U.K., and colleagues had previously discovered that they could slow the spin of rotaxane rotors 1000-fold with oscillating electric fields, which apparently polarize and strengthen the weak hydrogen bonds holding a ring to its thread. (sciencemag.org)