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nanotimes News in Brief

Scientists at the University of Groningen and at Empa have synthesised a molecule from four rotating motor units, i.e. wheels, which can travel straight ahead in a controlled manner.

“To do this, our car needs neither rails nor petrol; it runs on electricity. It must be the smallest elec- tric car in the world – and it even comes with 4-wheel drive” comments Empa researcher Karl- Heinz Ernst.

Images: Measuring approximately 4 x 2nm the molecular car is forging ahead on a copper surface on four electri- cally driven wheels. © EMPA / Nature

T. Kudernac, N. Ruangsupapichat, M. Parschau, B. Ma- cia, N. Katsonis, S.R. Harutyunyan, K.-H. Ernst, B.L. Feringa: Electrically driven directional motion of a four- wheeled molecule on a metal surface, In: Nature, Vol. 479(2011), Issue 7372, November 10, 2011, Pages 208- 211, DOI:10.1038/nature10587: http://dx.doi.org/10.1038/nature10587

http://www.youtube.com/watch?feature=player_ embedded&v=5A6qujxn34M Alexey Snezhko, Igor S. Aranson: Magnetic manipulation of self-assembled colloidal asters, In: Nature Materials, Vol. 10(2011), No. 9, September 2011, Pages 698-703, DOI:10.1038/nmat3083: http://dx.doi.org/10.1038/nmat3083

11-11/12 :: November/December 2011

Alexey Snezhko and Igor Aronson, physicists at the U.S. Department of Energy‘s (DOE) Argonne National Laboratory, have coaxed “micro-robots” to do their bidding. The robots, just half a millime- ter wide, are composed of microparticles. Confined between two liquids, they assemble themselves into star shapes when an alternating magnetic field is ap- plied. Snezhko and Aronson can control the robots‘ movement and even make them pick up, transport and put down other non-magnetic particles – po- tentially enabling fabrication of precisely designed functional materials in ways not currently possible. The discovery grew out of past work with magnetic “snakes”. This time, however, Snezhko and Aronson suspended the tiny ferromagnetic particles between two layers of immiscible, or non-mixing, fluids.