Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Just-For-Fun Experiment Creates Self-Assembly Method

14.12.2001


An experiment that University of Chicago physicists conducted just for fun has unexpectedly led them to a new technique for producing nanoscale structures.
The Chicago physicists have built simple electronic devices using the new technique, which precisely controls the growth of metal wires along tiny scaffolds that automatically assemble themselves following nature’s own tendencies.

"This is perhaps the first time that it has been possible to assemble large numbers of parallel, continuous wires that are truly nanometer scale in cross-section," said Heinrich Jaeger, Professor in Physics at the University of Chicago. Jaeger and Ward Lopes of Arryx Inc. in Chicago describe the technique in today’s issue of the journal Nature.


Self-assembly is a hot research field today because of the promise it holds for producing new technology at the nanoscale, the scale of atoms and molecules. Conventional methods for building smaller, faster computer components involves chiseling ever-finer structures out of a larger piece of material. Self-assembly, in contrast, builds up larger structures from smaller building blocks.

The nanowires that Lopes fabricated during the course of his Ph.D. research at the University measure 30 nanometers by 10 nanometers in diameter. A nanometer is a billionth of a meter, or the width of a double strand of DNA. Lopes also fabricated "nanochains," tiny strings of metal beads of similar size that could serve as switches.

The most perfect wirelike structures are formed with silver, Jaeger said. "Silver is unique in that it forms the wires. Essentially all other metals -- gold, copper, tin, lead, bismuth -- form nanochains under normal conditions.

"We can also form nanochains with silver, but the exciting advance of Ward’s research is that he was able to combine experimental results with computer simulations to get a feeling of what it is about a particular metal that makes it behave in a wirelike fashion or the chainlike fashion."

This productive line of research started on a lark.

"In Heinrich’s lab we had a tradition on Friday afternoons of doing experiments that you couldn’t justify spending time on, that you would only do because you wanted to have fun and try things out," Lopes said.

In his experiment, Lopes attempted to see if silver would chemically react to certain copolymers -- synthetic compounds -- the way gold did, as would be expected. But Lopes noticed that the silver exhibited strange behavior. All other metals formed balls on the copolymers and, if he added too much metal the balls would bond to each other and ignore the template. When he added enough silver he expected the silver to ignore the copolymer template, but the silver spheres had become long and thin.

"I just followed my nose and said, how long can I get these things to be?"

Potential applications for the technique include the production of high-density computer disks, and to make lenses for X-ray lithography, a process for transferring ultrasmall patterns to silicon computer chips.

The Chicago physicists used commonly available copolymers and simple methods with an eye toward easing the transfer of their results to potential applications.

"The plastics in the copolymer we used are standard, everyday plastics," Lopes said. "One was polystyrene, which is used to make Styrofoam, and the other, polymethylmethacrylate, is familiar from Plexiglas."

Steve Koppes | International Science News
Further information:
http://unisci.com/stories/20014/1213015.htm

More articles from Materials Sciences:

nachricht Watching atoms move in hybrid perovskite crystals reveals clues to improving solar cells
22.11.2017 | University of California - San Diego

nachricht Fine felted nanotubes: CAU research team develops new composite material made of carbon nanotubes
22.11.2017 | Christian-Albrechts-Universität zu Kiel

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New proton record: Researchers measure magnetic moment with greatest possible precision

High-precision measurement of the g-factor eleven times more precise than before / Results indicate a strong similarity between protons and antiprotons

The magnetic moment of an individual proton is inconceivably small, but can still be quantified. The basis for undertaking this measurement was laid over ten...

Im Focus: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

IceCube experiment finds Earth can block high-energy particles from nuclear reactions

24.11.2017 | Physics and Astronomy

A 'half-hearted' solution to one-sided heart failure

24.11.2017 | Health and Medicine

Heidelberg Researchers Study Unique Underwater Stalactites

24.11.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>