Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Metals Shape Up with a Little Help from Friends

After etching away the carbon material left from the use of intermediary polymers to organize the metal nanoparticles, the platinum structure features large (0.01 micrometers) hexagonal pores. The illustration depicts the completed porous platinum structure. This nanostructured platinum is the product of a radically innovative method for shaping metals developed by Cornell researchers. These porous metal structures have the capability to transform the development of catalysts for fuels cells and materials for microchip fabrication.

Credit: Courtesy of Scott Warren & Uli Wiesner, Cornell University
After etching away the carbon material left from the use of intermediary polymers to organize the metal nanoparticles, the platinum structure features large (0.01 micrometers) hexagonal pores. The illustration depicts the completed porous platinum structure. This nanostructured platinum is the product of a radically innovative method for shaping metals developed by Cornell researchers. These porous metal structures have the capability to transform the development of catalysts for fuels cells and materials for microchip fabrication.

Credit: Courtesy of Scott Warren & Uli Wiesner, Cornell University

Abstract:
New method 'self-assembles' metal atoms into porous nanostructures

Metals Shape Up with a Little Help from Friends

Arlington, VA | Posted on June 28th, 2008

For 5,000 years the only way to shape metal has been by the "heat and beat" technique. Even with modern nanotechnology, metalworking involves carving metals with electron beams or etching them with acid.

Now Cornell researchers have developed a method to self-assemble metals into complex configurations with structural details about 100 times smaller than a bacterial cell by guiding metal particles into the desired form using soft polymers.

"I think this is ingenious work that takes the fundamental concepts of polymer science and applies them to make metals in a totally novel way," said Andrew Lovinger, the director of the Polymers Program at the National Science Foundation. "In so doing, it opens the door to all kinds of new possibilities."

Applications include making more efficient and cheaper catalysts for fuel cells and industrial processes, and creating "plasmonic" surface structures capable of carrying more information across microchips than conventional wires do.

"The polymer community has tried to do this for almost 20 years," said Uli Wiesner, Cornell professor of materials science and engineering, who reports on the new method in the June 27, 2008, issue of the journal Science. "But metals have a tendency to cluster into uncontrolled structures."

Wiesner's research team has now developed a method to overcome this globby inclination of metals. First, metal nanoparticles measuring about 2 nanometers (nm) or 10-20 atoms in diameter, are coated with an organic material known as a ligand. The ligands form thin jackets around the metal atoms, changing their surface chemistry. Keeping the ligand jackets thinly tailored is a key factor that permits the volume of metal in the final structure to be large enough to hold its shape when the organic materials are eventually removed.

The jacketed metal atoms are then put in a solution containing block co-polymers, a kind of nano-scaffolding material. The innovative use of the ligands allows for the metal nanoparticles to be dissolved--even at high concentrations--in such a solution. A block co-polymer is made up of two different long chains, or blocks, of molecules linked together to form a predictable pattern. In the experiment, depicted in the illustration at right, ligand-coated platinum nanoparticles (shown as blue and gray balls) are nestled amongst the block co-polymers (shown as blue and green strands).

After the ligand-coated nanoparticles and polymers assemble in regular patterns, the material is heated to high temperatures in the absence of air to convert the polymers to a carbon scaffold. The scaffold is then allowed to cool. Because the metal nanoparticles have a very low melting point, without the carbon scaffold they would stubbornly fuse together in an uncontrolled fashion. Using this process, the carbon scaffold can be etched away with an acid, leaving behind a structured solid metal.

The Cornell group used the new method to create a platinum structure (see illustration above) with uniform hexagonal pores, each on the order of 10 nm across--a much larger diameter than previous attempts have been able to produce. Platinum is, so far, the best available catalyst for fuel cells, and a spacious pore structure allows fuel to flow through and react over a larger surface area.

"It opens a completely novel playground because no one has been able to structure metals in bulk ways using polymers," Wiesner explained. "In principle, if you can do it with one metal you can do it with others or even mixtures of metals."

In addition to making porous materials for catalysis, the researchers said, the technique could be used to create finely structured metals on surfaces, a key to transform the field of plasmonics, which studies the interactions among metal surfaces, light, and density waves of electrons, known as plasmons. Currently, researchers are investigating the use of plasmons to transmit more information across metal wires in microchips and to improve optics applications, like lasers, displays, and lenses.

The research team was led by Uli Wiesner at Cornell University and included Francis DiSalvo, the J.A. Newman Professor of Chemistry and Chemical Biology, and Sol Gruner, the John L. Wetherill Professor of Physics, both at Cornell, and other undergraduate and graduate students.

The research was funded by the National Science Foundation and the Cornell Fuel Cell Institute.

####

About National Science Foundation
The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering, with an annual budget of $6.06 billion. NSF funds reach all 50 states through grants to over 1,900 universities and institutions. Each year, NSF receives about 45,000 competitive requests for funding, and makes over 11,500 new funding awards. NSF also awards over $400 million in professional and service contracts yearly.

For more information, please click here

Contacts:
Media Contacts
Bill Steele
Cornell University
(607) 255-7164


Lisa-Joy Zgorski
National Science Foundation
(703) 292-8311


Brandon Michael Garcia
National Science Foundation
(703) 292-8612


Program Contacts
Andrew J. Lovinger
National Science Foundation
(703) 292-4933


Principal Investigators
Uli Wiesner, Cornell University
(607)255-3487

Copyright © National Science Foundation

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 Links

Uli Wiesner's Web Page

NSF Home Page

NSF News

For the News Media

Science and Engineering Statistics

Awards Searches

Related News Press

News and information

onic Present breakthrough in CMOS-based Transceivers for mm-Wave Radar Systems March 1st, 2015

Graphene Shows Promise In Eradication Of Stem Cancer Cells March 1st, 2015

Novel Method to Determine Optical Purity of Drug Components March 1st, 2015

Scientific breakthrough in rechargeable batteries: Researchers from Singapore and Québec Team Up to Develop Next-Generation Materials to Power Electronic Devices and Electric Vehicles February 28th, 2015

Self Assembly

Nanotubes self-organize and wiggle: Evolution of a nonequilibrium system demonstrates MEPP February 10th, 2015

Engineering self-assembling amyloid fibers January 26th, 2015

Revealed: How bacteria drill into our cells and kill them December 2nd, 2014

Live Images from the Nano-cosmos: Researchers watch layers of football molecules grow November 5th, 2014

Materials/Metamaterials

Moving molecule writes letters: Caging of molecules allows investigation of equilibrium thermodynamics February 27th, 2015

Graphene shows potential as novel anti-cancer therapeutic strategy: University of Manchester scientists have used graphene to target and neutralise cancer stem cells while not harming other cells February 26th, 2015

In quest for better lithium-air batteries, chemists boost carbon's stability: Nanoparticle coatings improve stability, cyclability of '3DOm' carbon February 25th, 2015

Learning by eye: Silicon micro-funnels increase the efficiency of solar cells February 25th, 2015

Announcements

onic Present breakthrough in CMOS-based Transceivers for mm-Wave Radar Systems March 1st, 2015

Graphene Shows Promise In Eradication Of Stem Cancer Cells March 1st, 2015

Novel Method to Determine Optical Purity of Drug Components March 1st, 2015

Scientific breakthrough in rechargeable batteries: Researchers from Singapore and Québec Team Up to Develop Next-Generation Materials to Power Electronic Devices and Electric Vehicles February 28th, 2015

Energy

In quest for better lithium-air batteries, chemists boost carbon's stability: Nanoparticle coatings improve stability, cyclability of '3DOm' carbon February 25th, 2015

New nanowire structure absorbs light efficiently: Dual-type nanowire arrays can be used in applications such as LEDs and solar cells February 25th, 2015

Learning by eye: Silicon micro-funnels increase the efficiency of solar cells February 25th, 2015

Magnetic nanoparticles enhance performance of solar cells X-ray study points the way to higher energy yields February 25th, 2015

Fuel Cells

Review highlights the potential for graphene and other 2D crystals in the energy sector February 4th, 2015

New concept of fuel cell for efficiency and environment: It grasps both performance efficiency and removal of toxic heavy metal ions in direct methanol fuel cells January 5th, 2015

Toward a low-cost 'artificial leaf' that produces clean hydrogen fuel December 3rd, 2014

Single-atom gold catalysts may offer path to low-cost production of fuel and chemicals November 28th, 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 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE