Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



Home > Press > Watching nanosheets and molecules transform under pressure could lead to stronger materials

Wang and colleagues used small angle X-ray diffraction (SAXRD) and wide-angle X-ray diffraction (WAXRD) to observe changes in the molecular structure of wurtzite crystal under pressure.
Wang and colleagues used small angle X-ray diffraction (SAXRD) and wide-angle X-ray diffraction (WAXRD) to observe changes in the molecular structure of wurtzite crystal under pressure.

Abstract:
Researchers have taken a potential step toward creating a new class of exceptionally strong, durable materials that maintain their high-pressure properties -- including strength and superconductivity -- in everyday low-pressure environments.

By Lauren Gold

Watching nanosheets and molecules transform under pressure could lead to stronger materials

Ithaca, NY | Posted on October 20th, 2010

When it comes to tests of strength, graphite -- actually layered sheets of carbon atoms -- fares badly. Subject it to ultra-high pressure, though, and graphite becomes diamond, the hardest substance known, and a uniquely useful material in a variety of applications.

But while diamonds may be forever, most materials that transform under high pressure revert to their original structure when the pressure is lifted -- losing any useful properties they may have gained when the squeeze was on.

Now, by understanding the process behind the transformation itself, from both experimental and theoretical perspectives, researchers have taken a potential step toward creating a new class of exceptionally strong, durable materials that maintain their high-pressure properties -- including strength and superconductivity -- in everyday low-pressure environments.

The research, led by Zhongwu Wang, staff scientist at the Cornell High Energy Synchrotron Source (CHESS) and including Roald Hoffmann, the 1981 chemistry Nobel laureate and Frank H.T. Rhodes Professor of Humane Letters Emeritus, appears in the Oct. 12, issue of the Proceedings of the National Academy of Sciences.

Additional scientists at CHESS, a group in Korea and a postdoctoral associate in the Hoffmann group, Xiao-dong Wen, also contributed.

Researchers frequently use X-ray diffraction, a technique in which X-rays are projected at a structure and captured on film after they pass through or bounce off its surfaces, to determine the static structures of atoms and molecules. But until now, the transformation and interaction between two structures happened in a metaphorical black box, said Wang.

To open the box, researchers focused on wurtzite, a cadmium-selenium crystal in which atoms are arranged in a diamondlike structure and molecules are bonded on the surface. When thin sheets of wurtzite are squeezed under 10.7 gigapascals of pressure, or 107,000 times the pressure on the Earth's surface, their atomic structure transforms into a rock salt-like structure

Subjecting a macro-sized crystal to high pressure can cause it to break (small defects in the crystal structure magnify, causing the structure, and the transformation process, to become irregular) -- so the group's Korean collaborators instead prepared wurtzite nanosheets, which are just 1.4 nanometers thick and defect-free.

As pressure was applied, Wang and colleagues integrated two X-ray diffraction techniques (small- and large-angle X-ray diffraction) to characterize changes in the crystal's surface shape and interior atomic structure, as well as the structural change of surface-bonded molecules.

They first discovered that the nanosheets required three times the pressure to undergo the transformation as the same material in larger crystal form.

They also tested the material's yield strength (the stress level at which it begins to deform), hardness (resistance to scratching or abrading) and elasticity (ability to return to its original form) during the transformation. Understanding how those properties change as the molecules interact could help researchers design stronger, tougher materials, Wang said.

And adding a bonding molecule called a soft ligand to the surface of the high-pressure nanosheets, the researchers observed the effect of that bonding to the nanosheets' internal structure, transformation pressure, and spacing.

Meanwhile, as Wang and colleagues performed the experiments at CHESS, Wen and Hoffmann worked on the corresponding theory behind the transformation interaction.

"Both the experiment and the simulation agree well," Wang said. "Now we know how the atoms move. We understand the intermediate procedure."

The next step is to test ways of blocking the reverse transformation from rock salt back to wurtzite, creating a material that maintains rock salt's unique properties under ambient pressure.

And Wang's experimental process could hold promise for understanding the transformation pathway for other compounds as well.

"It can apply to all other materials," Wang said. "Just follow our way of measurement."

The research was funded by the National Science Foundation.

####

For more information, please click here

Contacts:
Media Contact:
Blaine Friedlander
(607) 254-8093


Cornell Chronicle:
Lauren Gold
(607) 255-9736

Copyright © Cornell University

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

New class of protein misfolding simulated in high definition: Evidence for recently identified and long-lasting type of protein misfolding bolstered by atomic-scale simulations and new experiments August 8th, 2025

Sensors innovations for smart lithium-based batteries: advancements, opportunities, and potential challenges August 8th, 2025

Deciphering local microstrain-induced optimization of asymmetric Fe single atomic sites for efficient oxygen reduction August 8th, 2025

Lab to industry: InSe wafer-scale breakthrough for future electronics August 8th, 2025

Govt.-Legislation/Regulation/Funding/Policy

New imaging approach transforms study of bacterial biofilms August 8th, 2025

INRS and ELI deepen strategic partnership to train the next generation in laser science:PhD students will benefit from international mobility and privileged access to cutting-edge infrastructure June 6th, 2025

Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025

Institute for Nanoscience hosts annual proposal planning meeting May 16th, 2025

Possible Futures

ICFO researchers overcome long-standing bottleneck in single photon detection with twisted 2D materials August 8th, 2025

New molecular technology targets tumors and simultaneously silences two ‘undruggable’ cancer genes August 8th, 2025

Simple algorithm paired with standard imaging tool could predict failure in lithium metal batteries August 8th, 2025

First real-time observation of two-dimensional melting process: Researchers at Mainz University unveil new insights into magnetic vortex structures August 8th, 2025

Academic/Education

Rice University launches Rice Synthetic Biology Institute to improve lives January 12th, 2024

Multi-institution, $4.6 million NSF grant to fund nanotechnology training September 9th, 2022

National Space Society Helps Fund Expanding Frontier’s Brownsville Summer Entrepreneur Academy: National Space Society and Club for the Future to Support Youth Development Program in South Texas June 24th, 2022

How a physicist aims to reduce the noise in quantum computing: NAU assistant professor Ryan Behunin received an NSF CAREER grant to study how to reduce the noise produced in the process of quantum computing, which will make it better and more practical April 1st, 2022

Materials/Metamaterials/Magnetoresistance

First real-time observation of two-dimensional melting process: Researchers at Mainz University unveil new insights into magnetic vortex structures August 8th, 2025

Researchers unveil a groundbreaking clay-based solution to capture carbon dioxide and combat climate change June 6th, 2025

A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025

Institute for Nanoscience hosts annual proposal planning meeting May 16th, 2025

Announcements

Sensors innovations for smart lithium-based batteries: advancements, opportunities, and potential challenges August 8th, 2025

Deciphering local microstrain-induced optimization of asymmetric Fe single atomic sites for efficient oxygen reduction August 8th, 2025

Japan launches fully domestically produced quantum computer: Expo visitors to experience quantum computing firsthand August 8th, 2025

ICFO researchers overcome long-standing bottleneck in single photon detection with twisted 2D materials August 8th, 2025

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project