[meteorite-list] New Diamond Aerogel Is Lighter Than Ever

[Ron Baalke]

https://www.llnl.gov/news/newsreleases/2011/May/NR-11-05-05.html

For immediate release: 05/17/2011 | NR-11-05-05

New form of girl's best friend is lighter than ever
Lawrence Livermore National Laboratory
Anne M Stark, (925) 422-9799, stark8 at llnl.gov 

LIVERMORE, Calif. -- By combining high pressure with high temperature,
Livermore researchers have created a nanocyrstalline diamond aerogel
that could improve the optics for something as big as a telescope or as
small as the lenses in eyeglasses.

Aerogels are a class of materials that exhibit the lowest density,
thermal conductivity, refractive index and sound velocity of any bulk
solid. Aerogels are among the most versatile materials available for
technical applications due to their many exceptional properties. This
material has chemists, physicists, astronomers, and materials scientists
utilizing its properties in myriad applications, from a water purifier
for desalinizing seawater to installation on a NASA satellite as a
meteorite particle collector.

In new research appearing in the May 9 online edition of the Proceedings
of the National Academy of Sciences, a Livermore team created a diamond
aerogel from a standard carbon-based aerogel precursor using a
laser-heated diamond anvil cell.

A diamond anvil cell consists of two opposing diamonds with the sample
compressed between them. It can compress a small piece of material (tens
of micrometers or smaller) to extreme pressures, which can exceed 3
million atmospheres. The device has been used to recreate the pressure
existing deep inside planets, creating materials and phases not observed
under normal conditions. Since diamonds are transparent, intense laser
light also can be focused onto the sample to simultaneously heat it to
thousands of degrees.

The new form of diamond has a very low density similar to that of the
precursor of around 40 milligrams per cubic centimeter, which is only
about 40 times denser than air.

The diamond aerogel could have applications in antireflection coatings,
a type of optical coating applied to the surface of lenses and other
optical devices to reduce reflection. Less light is lost, improving the
efficiency of the system. It can be applied to telescopes, binoculars,
eyeglasses or any other device that may require reflection reduction. It
also has potential applications in enhanced or modified
biocompatibility, chemical doping, thermal conduction and electrical
field emission.

In creating diamond aergoels, lead researcher Peter Pauzauskie, a former
Lawrence fellow now at the University of Washington, infused the pores
of a standard, carbon-based aerogel with neon, preventing the entire
aerogel from collapsing on itself.

At that point, the team subjected the aerogel sample to tremendous
pressures and temperatures (above 200,000 atmospheres and in excess of
2,240 degrees Fahrenheit), forcing the carbon atoms within to shift
their arrangement and create crystalline diamonds.

The success of this work also leads the team to speculate that
additional novel forms of diamond may be obtained by exposing
appropriate precursors to the right combination of high pressure and
temperature.

Livermore researchers on the project include: Jonathan Crowhurst, Marcus
Worsley, Ted Laurence, Yinmin "Morris" Wang, Trevor Wiley, Kenneth
Visbeck, William Evans, Joseph Zaug and Joe Satcher Jr.


More Information

Synthesis and characterization of a nanocyrstalline diamond aerogel
<http://www.pnas.org/content/early/2011/05/02/1010600108.full.pdf+html?sid=5b693965-d508-400b-8c67-4be6f34a5f42>
Proceedings of the National Academy of Sciences, May 9, 2011

Improving Catalysis with a "Noble" Material
<https://str.llnl.gov/AprMay09/biener.html>
Science & Technology Review, April/May 2009

Advanced carbon aerogels for energy applications
<https://www.llnl.gov/news/aroundthelab/2011/Mar/ATL-031411.html>
Newsline, March 14, 2011

Novel Materials from Solgel Chemistry
<https://www.llnl.gov/str/May05/Satcher.html>
Science & Technology Review, May 2005

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