Navigation Links
In 'novel playground,' metals are formed into porous nanostructures
Date:6/26/2008

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

Now, Cornell researchers have developed a method to self-assemble metals into complex nanostructures. Applications include making more efficient and cheaper catalysts for fuel cells and industrial processes and creating microstructured surfaces to make new types of conductors that would carry more information across microchips than conventional wires do.

The method involves coating metal nanoparticles -- about 2 nanometers (nm) in diameter -- with an organic material known as a ligand that allows the particles to be dissolved in a liquid, then mixed with a block co-polymer (a material made up of two different chemicals whose molecules link together to solidify in a predictable pattern). When the polymer and ligand are removed, the metal particles fuse into a solid metal structure.

"The polymer community has tried to do this for 20 years," said Ulrich Wiesner, Cornell professor of materials science and engineering, who, with colleagues, reports on the new method in the June 27 issue of the journal Science. "But metals have a tendency to cluster into uncontrolled structures. The new thing we have added is the ligand, which creates high solubility in an organic solvent and allows the particles to flow even at high density."

Another key factor, he added, is to make the layer of ligand surrounding each particle relatively thin, so that the volume of metal in the final structure is large enough to hold its shape when the organic materials are removed.

"This is exciting," Wiesner said. "It opens a completely novel playground because no one has been able to structure metals in bulk ways. In principle, if you can do it with one metal you can do it with mixtures of metals."

Wiesner and two Cornell colleagues, Francis DiSalvo, the J.A. Newman Professor of Chemistry and Chemical Biology, and Sol Gruner, the John L. Wetherill Professor of Physics, as well as other researchers, report in Science how they used the new method to create a platinum structure with uniform hexagonal pores on the order of 10 nm across (a nanometer is the width of three silicon atoms). Platinum is, so far, the best available catalyst for fuel cells, and a porous structure allows fuel to flow through and react over a larger surface area.

The researchers began by mixing a solution of ligand-coated platinum nanoparticles with a block co-polymer. The solution of nanoparticles combines with just one of the two polymers. The two polymers assemble into a structure that alternates between small regions of one and the other, in this case producing clusters of metal nanoparticles suspended in one polymer and arranged around the outside of hexagonal shapes of the other polymer. Many other patterns are possible, depending on the choice of polymers.

The material is then annealed in the absence of air, turning the polymers into a carbon scaffold that continues to support the shape into which the metal particles have been formed. Wiesner and colleagues have previously used the carbon scaffold approach to create porous nanostructures of metal oxides.

The final step is to heat the material to a higher temperature in air to oxidize the ligands and burn away the carbon. Metal nanoparticles have a very low melting point at their surface, so the particles sinter together into a solid metal structure. The researchers have made fairly large chunks of porous platinum this way, up to at least a half-centimeter across.

In addition to making porous materials, the researchers said, the technique could be used to create finely structured surfaces, the key to the new field of plasmonics, in which waves of electrons move across the surface of a conductor with the information-carrying capacity of fiber optics, but in spaces small enough to fit on a chip.


'/>"/>

Contact: Blaine Friedlander
bpf2@cornell.edu
607-254-8093
Cornell University Communications
Source:Eurekalert

Related biology technology :

1. Novel Technology Breaks Through Cancer Pain
2. ThromboGenics Announces Successful Completion of Technology Transfer to Bharat Biotech for Production of Novel Thrombolytic Agent
3. XTL Biopharmaceuticals Announces Presentation of Novel Pre-Clinical Inhibitors of Hepatitis C at an Upcoming International Scientific Conference
4. Novel Angiogenic Drugs, Including a Future Blockbuster from Genzyme, Could Revolutionize Treatment of Peripheral Arterial Disease
5. New Licence for Cubicin(R) (daptomycin), the First in a Novel Class of Antibiotic, is Announced Today for the Treatment of Serious Bloodstream and Heart Infections Caused by the Most Problematic UK Organisms, Including MRSA
6. NIST team develops novel method for nanostructured polymer thin films
7. GlaxoSmithKline Awarded U.S. Department of Defense Contract to Pursue Novel Antibacterial Research Program
8. Arpida Invited to Present Preclinical Data on Novel Topical Antibiotic AR-2474 at ICAAC
9. European Expert Consortium Combines Forces to Develop a Novel Pandemic Influenza Vaccine
10. NexGenix Pharmaceuticals Enters into Exclusive World-wide License to Develop Novel Hsp90 Inhibitors
11. GenVault and the National Center for Forensic Science to Present Novel Technology for Room Temperature Storage of RNA
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/23/2016)... , June 23, 2016   EpiBiome , ... secured $1 million in debt financing from Silicon Valley ... up automation and to advance its drug development efforts, ... new facility. "SVB has been an incredible ... the services a traditional bank would provide," said Dr. ...
(Date:6/23/2016)... ... June 23, 2016 , ... STACS DNA Inc., the sample tracking software company, ... Crime Laboratory, has joined STACS DNA as a Field Application Specialist. , “I ... President and COO of STACS DNA. “In further expanding our capacity as a scientific ...
(Date:6/23/2016)... 2016 Apellis Pharmaceuticals, Inc. today announced ... of its complement C3 inhibitor, APL-2. The trials ... dose studies designed to assess the safety, tolerability, ... in healthy adult volunteers. Forty subjects ... single dose (ranging from 45 to 1,440mg) or ...
(Date:6/23/2016)... 23, 2016 Andrew ... http://doi.org/10.17925/OHR.2016.12.01.22 Published recently in ... journal from touchONCOLOGY, Andrew D Zelenetz , ... cancer care is placing an increasing burden on ... biologic therapies. With the patents on many biologics ...
Breaking Biology Technology:
(Date:6/3/2016)... , June 3, 2016 ... von Nepal hat ... Lieferung hochsicherer geprägter Kennzeichen, einschließlich Personalisierung, Registrierung ... in der Produktion und Implementierung von Identitätsmanagementlösungen. ... Ausschreibung im Januar teilgenommen, aber Decatur wurde ...
(Date:6/1/2016)... NEW YORK , June 1, 2016 ... Biometric Technology in Election Administration and Criminal Identification to ... According to a recently released TechSci Research report, " ... Sector, By Region, Competition Forecast and Opportunities, 2011 - ... $ 24.8 billion by 2021, on account of growing ...
(Date:5/12/2016)... May 12, 2016 WearablesResearch.com , a ... the overview results from the Q1 wave of its ... wave was consumers, receptivity to a program where they ... a health insurance company. "We were surprised ... says Michael LaColla , CEO of Troubadour Research, ...
Breaking Biology News(10 mins):