Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > When molecules leave tire tracks

Abstract:
A new approach to optimizing molecular self-organization

When molecules leave tire tracks

Munich | Posted on February 18th, 2010

Some classes of molecules are capable of arranging themselves in specific patterns on surfaces. This ability to self-organize is crucial for many technological applications, which are dependend on the assembly of ordered structures on surfaces. However, it has so far been virtually impossible to predict or control the result of such processes. Now a group of researchers led by Dr. Bianca Hermann, a physicist from the Center for Nanoscience (CeNS) at LMU Munich, reports a significant breakthrough: By combining statistical physics and detailed simulations with images obtained by scanning tunnelling microscopy (STM), the team has been able to formulate a simple model that can predict the patterns observed. "With the help of the model, we can generate a wide variety of patterns that reproduce surprisingly well the arrangements observed experimentally", says Hermann. "We want to extend this approach to other surface symmetries. Already now the areas of molecular electronics, sensor applications, surface catalysis and organic photovoltaics can profit from our model. Its ability to predict structures formed by self-organization allows optimization of molecular building blocks prior to synthesis." (NanoLetters online, 16 February 2010)

When "mother nature" does the engineering, molecules can self-organize into complex structures - a first step in the formation of membranes, cells and other molecular systems. The principle of self-organization, which allows very economical use of resources, is also exploited in the production of functionalized surfaces required in molecular electronics, sensor applications, catalysis and photovoltaic components. The idea of the manufacturing process is that molecular components are brought into contact with a substrate material, and then "magically" find their preferred positions in the desired molecular network. The starting components are selected to display specific structural and chemical features intended for the envisaged application. However, the optimization of the molecular adlayers depends largely on a trial-and-error approach, and is therefore complicated and time-consuming.

To develop the new molecular-interaction site model, Dr. Herrmann's group collaborated with Priv. Doz. Dr. Thomas Franosch und Professor Erwin Frey within the Cluster of Excellence "Nanosystems Initiative Munich" (NIM). The problem was tackled using an approach from statistical physics known as Monte Carlo method, which allows one to conduct a detailed computer simulation on the statistics of molecular interactions. The structural motifs so generated were compared with experimental high-resolution images of molecular patterns obtained by STM. Marta Balbás Gambra, a doctoral student, began each simulation with a mathematical representation of a collection of hundreds of randomly oriented particles of defined conformation. These schematic molecules were then perturbed by - computationally - adding energy, causing the population to adopt a new configuration.

Using this simulation strategy, one can generate a greater variety of patterns than are found naturally, and many of these corresponded closely to the real molecular patterns revealed by STM. "In one case we actually predicted a pattern that was only later verified with STM", reports doctoral student Carsten Rohr. According to the laws of thermodynamics, physical systems tend to adopt the state with the most favourable (i.e. lowest) energy. Experimental tests showed that different molecular configurations interconvert until an arrangement predominates that is reminiscent of tyre tracks. And indeed, the Monte Carlo approach had predicted that this arrangement corresponds to the state with the lowest energy.

"In the end, we were able to show that the molecular geometry and a few salient features encode the structural motifs observed", explains theorist Franosch. "We plan to extend the approach to other types of surface symmetries, but the model already provides an important theoretical tool, because it helps us to forecast the type of surface pattern that a given functional molecule will form. This means that the design of molecules can be optimized during the synthetic phase, so as to obtain surfaces with the desired characteristics", says Hermann. The physicists in the group, who come from different scientific backgrounds and were able to pool their expertise for this project, envisage multiple potential applications for their model in molecular electronics, sensor technology, catalysis and photovoltaics. Further possibilities include its use for predicting the results of other types of molecular interactions also on partially patterned substrates. (suwe)


Publication:
"Molecular Jigsaw: Pattern Diversity Encoded by Elementary Geometrical Features",
C. Rohr, M. Balbás Gambra, K. Gruber, E. C. Constable, E. Frey, T. Franosch, and B. A. Hermann
NanoLetters online, 16 February 2009
DOI: 10.1021/nl903225j

####

About Ludwig-Maximilians-Universitaet Muenchen
With degree programs available in 150 subjects in numerous combinations, the array of courses we have to offer is extremely wide. Some 44,000 students, 15 percent of whom come to us from abroad, are currently taking advantage of these opportunities. They view their studies as an investment in the future, a launching pad for their later careers.

LMU Munich takes the education of young people very seriously. When we speak of academic diversity, we also mean a comprehensive education that encompasses social skills alongside a critical awareness of values and history. This includes the Munich legacy of the Weisse Rose, the student-based resistance group that opposed Nazism.

We put our faith in open minds, imagination and promising ideas – that’s why I invite you to join us to learn, teach and conduct research at LMU Munich!

Professor Dr. Bernd Huber
President, Ludwig-Maximilians-Universität München

For more information, please click here

Contacts:
Dr. Bianca Hermann
Cluster of Excellence “Nanosystems Initiative Munich“ (NIM) and Center for NanoScience (CeNS), LMU Munich; Walther Meissner Institute of the Bavarian Academy of Sciences and Humanities
Phone: +49 (0) 89 / 289 14258
Fax: +49 (0) 89 / 289 14206

www.wmi.badw-muenchen.de/spm

Copyright © Ludwig-Maximilians-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

Feynman Prize Winners Announced! April 26th, 2015

New ASTM Standards Will Help Educate Present and Future Nanotechnology Workforces April 26th, 2015

Heat makes electrons’ spin in magnetic superconductors April 26th, 2015

QD Vision Wins 2015 Bronze Edison Award for Color IQ™ Quantum Dot Technology April 26th, 2015

Self Assembly

Scientists Use Nanoscale Building Blocks and DNA 'Glue' to Shape 3D Superlattices: New approach to designing ordered composite materials for possible energy applications April 23rd, 2015

Advances in molecular electronics: Lights on -- molecule on: Researchers from Dresden and Konstanz succeed in light-controlled molecule switching April 20th, 2015

Carnegie Mellon chemists create tiny gold nanoparticles that reflect nature's patterns April 9th, 2015

DWI scientists program the lifetime of self-assembled nanostructures April 9th, 2015

Discoveries

Heat makes electrons’ spin in magnetic superconductors April 26th, 2015

SEFCU, SUNY Poly CNSE Announce Winning Student-Led Teams in the 6th Annual $500,000 New York Business Plan Competition April 25th, 2015

Northwestern scientists develop first liquid nanolaser: Technology could lead to new way of doing 'lab on a chip' medical diagnostics April 25th, 2015

Fast and accurate 3-D imaging technique to track optically trapped particles April 24th, 2015

Announcements

Feynman Prize Winners Announced! April 26th, 2015

New ASTM Standards Will Help Educate Present and Future Nanotechnology Workforces April 26th, 2015

Heat makes electrons’ spin in magnetic superconductors April 26th, 2015

QD Vision Wins 2015 Bronze Edison Award for Color IQ™ Quantum Dot Technology April 26th, 2015

Tools

Fast and accurate 3-D imaging technique to track optically trapped particles April 24th, 2015

ORNL reports method that takes quantum sensing to new level April 23rd, 2015

Quantum 'paparazzi' film photons in the act of pairing up April 22nd, 2015

Richards-Kortum elected to American Academy of Arts and Sciences: April 22nd, 2015

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