Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NC State Chemist Creates Structure in Amorphous Materials

27.09.2002


A chemist at North Carolina State University has made breakthrough discoveries that advance basic understandings of the nature of liquids and glasses at the atomic and molecular levels. Featured in the Sept. 26 issue of Nature, these discoveries could lead to the development of totally new materials with useful optical and electronic properties - as well as applications not yet foreseen.


Dr. James Martin uses colorful analogies to explain his current research



Liquids and glass have long been understood by scientists to be amorphous, meaning "without structure." Cartoon pictures in textbooks of atomic arrangements frequently represent liquids to be much like gases, a collection of molecules moving around randomly.

Not so, according to Dr. James D. Martin, associate professor of chemistry at NC State. "Just as a symphony is much more than a collection of random notes, the atoms and molecules in a liquid are quite organized - more like those in a crystal than a gas."


With this new understanding of liquid molecular organization comes the ability to reorganize liquids.

Martin and his colleagues have discovered the chemical principles that allow them to essentially write new "symphonic compositions" in amorphous materials. They have designed the compositions and structure of several glasses and liquids, then gone into the laboratory and made them.

Due to this new ability to design such structures, it will be possible to engineer specific optical and electronic properties of glasses and liquids. This amorphous-material engineering creates the materials foundation for future technologies.

What led to this important discovery? Martin specializes in the structure and physical properties of inorganic materials. His work involves engineering crystals to produce materials with desired properties.

Several years ago, Martin noticed that as he designed and synthesized crystals, he also produced a lot of liquid and glassy blobs. He originally dismissed the blobs as trash, but became curious about them because they appeared so frequently. His curiosity led him into the study of the molecular structure of liquids and glasses, an area not well understood by science.

The first hint of the presence of structure in liquids emerged in 1916, as scientists experimented with the X-ray diffraction of liquids. They observed structural features indicating some organization of molecules, but the organization was far less than is necessary for a crystal. Since that initial discovery, there has been significant scientific debate about whether the structure in liquids is crystal-like or random.

Upon melting into a liquid, most solids undergo a very small change in volume, suggesting that the interactions holding molecules together in liquids, glasses and crystals are quite similar.

Despite these clues, scientists still have only a limited knowledge about the structure of liquids and glasses. In a typical freshman chemistry textbook, there are multiple pages on gases and solids, yet only a paragraph or two on liquids.

"That’s the mystery. What is the structure of something that’s not supposed
to have a structure?" Martin said. "If similar bonding interactions hold molecules in liquids, glasses and crystals, then it should be possible to engineer the structure in liquids and glasses just like it’s possible to engineer the structure of crystals."

An analogy occurred to him as Martin stared at the crystal models he’d made by gluing tennis balls together, and then watched his children "swim" through big playpens filled with plastic balls. "Picture the balls as molecules," Martin said. "No matter how kids may move around in the playpen, the balls always touch each other in about the same way. And the arrangement of the balls looks very much like my tennis-ball crystal models."

This new understanding of the structure of liquids and glasses suggests the possibility of engineering new liquids and glasses. "If you understand the network’s structure, and the chemical bonds within the structure, you can manipulate the structure," said Martin. "And if you change the structure, you change the properties."

In his laboratories at NC State, Martin and graduate student Steve Goettler have proven this by introducing molecules of a different substance into glasses and liquids. The foreign molecules are engineered at the atomic level to "fit" within the liquid’s structure and interact with the liquid’s own molecules. The presence of the foreign molecules changes the liquid’s properties. Different concentrations of the foreign molecules also change the structure, and thus produce more changes in the liquid’s properties.

To prove the structural relationships between their amorphous materials and model crystal structures, Martin’s research group took their engineered liquids and glasses to Argonne National Laboratory. There they are able to look at the atomic organization of their materials using a glass, liquids and amorphous materials diffractometer (GLAD) instrument at Argonne’s national user facility.

Martin’s work, funded by the National Science Foundation, opens a new area of scientific research: amorphous materials engineering. He foresees the ability to control the optical and electronic properties of glasses to produce specialized materials that will advance optical computing and communications technologies, among other applications. "This new understanding," he said, "allows us to create the materials that will be the foundation of tomorrow’s technology."

At the very least, someone will have to rewrite a lot of chemistry textbooks.

Dr. James D. Martin | EurekAlert!
Further information:
http://www.ncsu.edu/

More articles from Life Sciences:

nachricht Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY

nachricht NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>