Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button

Home > Press > Self-assembly of nano-rotors

A Nano-rotor in its honeycomb-cage
A Nano-rotor in its honeycomb-cage

Abstract:
Mechanical engineering at the molecular level

Self-assembly of nano-rotors

München | Posted on November 24th, 2010

Scientists from the Technische Universitaet Muenchen (TUM) have managed to direct the self-assembly of rod-shaped molecules into rotors only few nanometers in size. The tiny systems serve the study of forces that act on molecules on surfaces and in cage-like structures. Their findings are published in the current online issue of the Proceedings of the National Academy of Sciences (USA).

In the nanoworld many things are different. Scientists only recently started unveiling and harnessing the underlying laws and principles. In cooperation with chemists associated with Professor Mario Ruben at the Karlsruhe Institute of Technology Professor Johannes Barth and his team from the Physics Department of the TU Muenchen have now succeeded in capturing rod-shaped molecules in a two-dimensional network in such a way that they autonomously form small rotors that turn in their honeycomb-like cages.

Nature itself provides the role model for such self-organizing systems. This is how proteins bring reactants so close together that reactions can take place - reactions that are possible only in very close proximity. These effects are put to use in catalysts: surface reactants find their way to each other on the surface of these facilitators. However, the coveted dream of using self-organization effects in such a way that nano machines assemble themselves is still a thing of the future.

The rotors developed in Garching are an important step in this direction. First, the physicists built up an extensive nano lattice by allowing cobalt atoms and rod-shaped molecules of sexiphenyl-dicarbonitrile to react with each other on a silver surface. This results in a honeycomb-like lattice of extreme regularity with astonishing stability. Just like graphene, for which its discoverers were awarded the Nobel Prize only a few weeks ago, this lattice is exactly one atom thick.

When the researchers added further molecular building blocks, the rods spontaneously gathered, typically in groups of three, in a honeycomb cell while neighboring cells remained empty. The chummy molecules must have had a reason for organizing themselves in threesomes. Under a scanning tunneling microscope the scientists were able to recognize why. The three molecules oriented themselves in such a way that the nitrogen ends each faced a phenyl-ring hydrogen atom. This triple-bladed rotor arrangement is so energetically advantageous that the molecules maintain this structure even when thermal energy drives it to rotation.

Because the honeycomb-cell is not round, but hexagonal, there are two different positions for the rotors that can be distinguished as a result of the interactions between the outer nitrogen atoms and the hydrogen atoms of the cell wall. Furthermore, the three molecules arrange in a clockwise and a counter-clockwise manner. In experiments at various carefully controlled temperatures the physicists were able to "freeze" all four states and examine them closely. They could thus determine the energy of these thresholds from the temperature at which the rotation resumed.

"We hope that in future we will be able to extend these simple mechanical models to optical or electronic switching," says Professor Johannes Barth. "We can set a specific cell size, we can specifically bring in further molecules and study their interaction with the surface and the cell wall. These self-organizing structures hold enormous potential."

The research was funded by the European Union (ERC Advanced Grant MolArt), as well as from the Institute for Advanced Study (TUM-IAS), the International Graduate School for Science and Engineering (IGSSE) and the Catalysis Research Center (CRC) at the TU Muenchen. The publication resulted from the collaboration with scientists at the Institute of Nanotechnology of the Karlsruhe Institute of Technology and the Institute of Material Physics and Chemistry of the University of Strasbourg.

Original publication:

Rotational and constitutional dynamics of caged supramolecules,
Dirk Kühne, Florian Klappenberger, Wolfgang Krenner, Svetlana Klyatskaya, Mario Ruben und Johannes V. Barth,

PNAS Early Edition, online November 22, 2010 - DOI: 10.1073/pnas.1008991107

####

For more information, please click here

Contacts:
Prof. Johannes V. Barth
Technische Universitaet Muenchen
Department of Physics, E20
James-Franck-Str. 1, 85748 Garching, Germany
Tel: +49 89 289 12608
Fax: +49 89 289 12338


Copyright © Technische Universitaet Muenchen

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Nanoparticle versus cancer: Scientists have created nanoparticles which cure cancer harmlessly July 22nd, 2016

Quantum drag:University of Iowa physicist says current in one iron magnetic sheet can create quantized spin waves in another, separate sheet July 22nd, 2016

New Yale-developed device lengthens the life of quantum information July 22nd, 2016

RMIT researchers make leap in measuring quantum states July 21st, 2016

Govt.-Legislation/Regulation/Funding/Policy

Quantum drag:University of Iowa physicist says current in one iron magnetic sheet can create quantized spin waves in another, separate sheet July 22nd, 2016

Weird quantum effects stretch across hundreds of miles July 21st, 2016

Scientists glimpse inner workings of atomically thin transistors July 21st, 2016

The birth of quantum holography: Making holograms of single light particles! July 21st, 2016

Possible Futures

Nanoparticle versus cancer: Scientists have created nanoparticles which cure cancer harmlessly July 22nd, 2016

Quantum drag:University of Iowa physicist says current in one iron magnetic sheet can create quantized spin waves in another, separate sheet July 22nd, 2016

New Yale-developed device lengthens the life of quantum information July 22nd, 2016

Research team led by NUS scientists develop plastic flexible magnetic memory device: Novel technique to implant high-performance magnetic memory chip on a flexible plastic surface without compromising performance July 21st, 2016

Academic/Education

News from Quorum: The College of New Jersey use the Quorum Cryo-SEM preparation system in a project to study ice crystals in high altitude clouds July 19th, 2016

Leti and Korea Institute of Science and Technology to Explore Collaboration on Advanced Technologies for Digital Era July 14th, 2016

SUNY Poly Celebrates Its 10th Year Exhibiting at SEMICON West with Cutting Edge Developments in Integrated Photonics and Power Electronics July 8th, 2016

FEI and King Abdullah University of Science and Technology Establish New Electron Microscopy ‘Centre of Excellence’: Centre of Excellence involves materials and life sciences research and technical collaboration July 5th, 2016

Self Assembly

WSU researchers develop shape-changing 'smart' material: Heat, light stimulate self-assembly July 4th, 2016

Building a smart cardiac patch: 'Bionic' cardiac patch could one day monitor and respond to cardiac problems June 28th, 2016

Self-assembling icosahedral protein designed: Self-assembling icosahedral protein designed June 22nd, 2016

DNA shaping up to be ideal framework for rationally designed nanostructures: Shaped DNA frames that precisely link nanoparticles into different structures offer a platform for designing functional nanomaterials June 14th, 2016

Announcements

Nanoparticle versus cancer: Scientists have created nanoparticles which cure cancer harmlessly July 22nd, 2016

Quantum drag:University of Iowa physicist says current in one iron magnetic sheet can create quantized spin waves in another, separate sheet July 22nd, 2016

New Yale-developed device lengthens the life of quantum information July 22nd, 2016

Graphene photodetectors: Thinking outside the 2-D box July 21st, 2016

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







Car Brands
Buy website traffic