Imagine a three-part nanometric motor. It is adsorbed on a gold surface by the stator. A ruthenium atom, acting as a ball bearing, on the tip of the stator is connected to a five-arm 2-nanometer diameter molecular rotor. One arm of the rotor has been deliberately shortened to follow rotor rotation direction. A mere 200 atoms make up the molecular motor whose design and synthesis required no fewer than 15 stages and took CEMES researchers working with their US counterparts at the University of Ohio nearly ten years to engineer.
Three connection points anchor the 'molecular motor' onto a surface. The upper plate turns clockwise or counterclockwise around its axis, depending on the position of the microscope point. Crédits : G. Rapenne et G. Vives, CEMES, CNRS/UPS
Step-by-step, the researchers managed to trigger rotor movement and control rotational direction by placing the molecular device on a gold surface and subjecting it to a temperature of - 268.5°C, i.e. 4.6°C from absolute zero. To do so, electrons were delivered with the point of a tunneling microscope, serving as an observation instrument and energy source. The research, which foreshadows the components of future nanometric robots, was published in the January issue of Nature Nanotechnologies. The researchers' next step will be to measure the power delivered by the nano-motor by having it interact with the smallest solid gears that can be made today.
- Controlled clockwise and anticlockwise rotational switching of a molecular motor - U. G. E. Perera, F. Ample, H. Kersell, Y. Zhang, G. Vives, J. Echeverria, M. Grisolia, G. Rapenne, C. Joachim and S.-W. Hla - Nature Nanotechnology, 2013, 8, 46-51.