Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > All Smoothed Out

Gold service: The asperities on a polished gold surface are quickly dissolved by the OH. radicals of Fentons reagent. The dissolution of Au is rapid at the beginning of the reaction and is negligible when the asperities have been dissolved. Although the OH. radicals also oxidize the smooth parts of the Au surface, they do not dissolve them, but form a stable oxide monolayer.
Gold service: The asperities on a polished gold surface are quickly dissolved by the OH. radicals of Fentons reagent. The dissolution of Au is rapid at the beginning of the reaction and is negligible when the asperities have been dissolved. Although the OH. radicals also oxidize the smooth parts of the Au surface, they do not dissolve them, but form a stable oxide monolayer.

Abstract:
Hydroxyl radicals remove nanoscopic irregularities on polished gold surfaces

All Smoothed Out

Weinheim, Germany | Posted on January 14th, 2010

The precious metal gold is the material of choice for many technical applications because it does not corrode - and because it also has interesting electrical, magnetic, and optical properties. Gold is thus one of the most important metals in the electronics industry, miniaturized optical components, and electrochemical processes. In these applications, it is extremely important that the surface of the gold be completely clean and smooth. However, conventional processes not only "polish" away the undesirable irregularities, but also attack the gold surface. Fritz Scholz and a team from the Universities of Greifswald (Germany) and Warsaw (Poland) have now discovered a technique that can differentiate between the two. As the scientists report in the journal Angewandte Chemie, hydroxyl radicals (OH radicals) rapidly remove all tiny protrusions on mechanically polished gold surfaces, leaving behind an extremely smooth surface.

The researchers treated gold surfaces with Fenton's reagent, which is a mixture of hydrogen peroxide and iron(II) salts that releases OH radicals. It is also used to degrade organic impurities in the purification of waste water. "Actually, it was not expected that the radicals would attack a polished pure gold surface," says Scholz, "because gold is notoriously difficult to oxidize." The experiments demonstrated that the hydroxyl radicals oxidize gold very well, though measurable dissolution continues only as long as there are still bumps on the gold surface. Though these results seem contradictory at first glance, the researchers explain that the reaction of the radicals with the highly ordered gold atoms of the completely smooth surface produces a stable layer of gold oxide, which can be reduced back to elemental gold without a significant loss of material. In the protrusions, however, the gold atoms are less ordered and very reactive. During the oxidation, they detach themselves from the atomic structure.

"Because the protrusions are selectively removed, our method is very interesting for polishing gold surfaces for industrial applications," says Scholz. The process may also find a use in medical technology: gold is used to replace teeth, in tissues for reconstructive surgery, and in electrode implants, such as those used for implanted hearing aids. These release tiny amounts of gold, which enters into the surrounding tissue. This apparently occurs because of an immune reaction that results in the formation of OH radicals or similar species. Pre-treatment of gold implants with Fenton's reagent could inhibit this release of gold into the body.

Author: Fritz Scholz, Universität Greifswald (Germany),

www.chemie.uni-greifswald.de/~analytik/

Title: Hydroxyl Radicals Attack Metallic Gold

Angewandte Chemie International Edition, Permalink: dx.doi.org/10.1002/anie.200906358

####

About Wiley InterScience
Wiley InterScience (www.interscience.wiley.com) provides access to over 3 million articles across nearly 1500 journals and 7000 Online Books and major reference works. It also holds industry leading databases such as The Cochrane Library, chemistry databases and the acclaimed Current Protocols laboratory manuals.

Wiley InterScience is one of the world's premiere resources for study, teaching and advanced research.

For more information, please click here

Contacts:
Editorial office


Amy Molnar (US)


Jennifer Beal (UK)


Alina Boey (Asia)

Copyright © Wiley InterScience

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

MRI, on a molecular scale: Researchers develop system that could one day peer into the atomic structure of individual molecules April 20th, 2014

Iranian Researchers Present New Model to Strengthen Superconductivity at Higher Temperatures April 19th, 2014

Iranian Researchers Produce New Anti-Cancer Drug from Turmeric April 19th, 2014

Innovative strategy to facilitate organ repair April 18th, 2014

Chemistry

Thinnest feasible membrane produced April 17th, 2014

Targeting cancer with a triple threat: MIT chemists design nanoparticles that can deliver three cancer drugs at a time April 15th, 2014

Scientists Succeed in Simultaneous Determination of Acetaminophen, Codeine in Drug Samples April 9th, 2014

Good vibrations: Using light-heated water to deliver drugs - Researchers use near-infrared light to warm water-infused polymeric particles April 1st, 2014

Possible Futures

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

Local girl does good March 22nd, 2014

Surface Characteristics Influence Cellular Growth on Semiconductor Material March 12th, 2014

The "Tipping Point" February 12th, 2014

Chip Technology

'Exotic' material is like a switch when super thin April 18th, 2014

Scientists open door to better solar cells, superconductors and hard-drives: Research enhances understanding of materials interfaces April 14th, 2014

Obducat has launched a new generation of SINDRE® Nano Imprint production system April 11th, 2014

Scientists in Singapore develop novel ultra-fast electrical circuits using light-generated tunneling currents April 10th, 2014

Nanomedicine

Iranian Researchers Present New Model to Strengthen Superconductivity at Higher Temperatures April 19th, 2014

Iranian Researchers Produce New Anti-Cancer Drug from Turmeric April 19th, 2014

Innovative strategy to facilitate organ repair April 18th, 2014

High-temperature plasmonics eyed for solar, computer innovation April 17th, 2014

Discoveries

MRI, on a molecular scale: Researchers develop system that could one day peer into the atomic structure of individual molecules April 20th, 2014

Iranian Researchers Present New Model to Strengthen Superconductivity at Higher Temperatures April 19th, 2014

Iranian Researchers Produce New Anti-Cancer Drug from Turmeric April 19th, 2014

'Exotic' material is like a switch when super thin April 18th, 2014

Announcements

MRI, on a molecular scale: Researchers develop system that could one day peer into the atomic structure of individual molecules April 20th, 2014

Iranian Researchers Present New Model to Strengthen Superconductivity at Higher Temperatures April 19th, 2014

Iranian Researchers Produce New Anti-Cancer Drug from Turmeric April 19th, 2014

Innovative strategy to facilitate organ repair April 18th, 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