Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

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

Shaping the Future of Nanocrystals: Berkeley Lab Researchers Obtain First Direct Observation of Facet Formation in Nanocubes August 21st, 2014

Hiden Release New Gas Analysis Catalogue August 21st, 2014

Wyatt Technology’s 24th International Light Scattering Colloquium to Highlight Developments in Applications and Characterization of Nanoparticles August 21st, 2014

Water window imaging opportunity: A new theoretical study elucidates mechanisms that could help in producing coherent radiations, ultimately promoting high-contrast imaging of biological samples August 21st, 2014

Govt.-Legislation/Regulation/Funding/Policy

Shaping the Future of Nanocrystals: Berkeley Lab Researchers Obtain First Direct Observation of Facet Formation in Nanocubes August 21st, 2014

Success in Intracellular Imaging of Cesium Distribution in Plants Used for Cesium Absorption August 19th, 2014

Electrical engineers take major step toward photonic circuits: Team invents non-metallic metamaterial that enables them to 'compress' and contain light August 19th, 2014

Promising Ferroelectric Materials Suffer From Unexpected Electric Polarizations: Brookhaven Lab scientists find surprising locked charge polarizations that impede performance in next-gen materials that could otherwise revolutionize data-driven devices August 18th, 2014

Possible Futures

Air Force’s 30-year plan seeks 'strategic agility' August 1st, 2014

IBM Announces $3 Billion Research Initiative to Tackle Chip Grand Challenges for Cloud and Big Data Systems: Scientists and engineers to push limits of silicon technology to 7 nanometers and below and create post-silicon future July 10th, 2014

Virus structure inspires novel understanding of onion-like carbon nanoparticles April 10th, 2014

Local girl does good March 22nd, 2014

Academic/Education

SEMATECH and Newly Merged SUNY CNSE/SUNYIT Launch New Patterning Center to Further Advance Materials Development: Center to Provide Access to Critical Tools that Support Semiconductor Technology Node Development August 7th, 2014

Oxford Instruments Asylum Research and the Center for Nanoscale Systems at Harvard University Present a Workshop on AFM Nanomechanical and Nanoelectrical Characterization, Aug. 21-22 August 6th, 2014

University of Manchester selects Anasys AFM-IR for coatings and corrosion research July 30th, 2014

Haydale Announces Collaboration Agreement with Swansea University’s Welsh Centre for Printing and Coatings (WCPC) July 12th, 2014

Self Assembly

Nanocubes Get in a Twist : Competing forces coax nanocubes into helical structures August 11th, 2014

Self-assembly of gold nanoparticles into small clusters August 4th, 2014

Carnegie Mellon Chemists Create Nanofibers Using Unprecedented New Method July 31st, 2014

Berkeley Lab researchers create nanoparticle thin films that self-assemble in 1 minute June 9th, 2014

Announcements

Wyatt Technology’s 24th International Light Scattering Colloquium to Highlight Developments in Applications and Characterization of Nanoparticles August 21st, 2014

Ultra-short pulse lasers & Positioning August 21st, 2014

Malvern’s Dr Alan Rawle talks TLAs in plenary lecture at Particulate Systems Analysis conference August 21st, 2014

Water window imaging opportunity: A new theoretical study elucidates mechanisms that could help in producing coherent radiations, ultimately promoting high-contrast imaging of biological samples August 21st, 2014

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







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE