Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Theory Explains Mysterious Nature of Glass

01.10.2008
The history of glass dates back 5,000 years, yet its nature still perplexes scientists. How do glassy materials make the transition from a molten state to a solid? Richard Wool, professor of chemical engineering at the University of Delaware, thinks he has the answer -- Twinkling Fractal Theory.

Archaeological evidence suggests that glass was first made in the Middle East sometime around 3000 B.C. However, almost 5,000 years later, scientists are still perplexed about how glassy materials make the transition from a molten state to a solid. Richard Wool, professor of chemical engineering at UD, thinks he has the answer.

What distinguishes glasses from other materials is that even after hardening, they retain the molecular disorder of a liquid. In contrast, other liquids--for example, water--assume an ordered crystal pattern when they harden. Glass does not undergo such a neat phase transition; rather, the molecules simply slow down gradually until they are stuck in an odd state somewhere between a liquid and a solid.

In a paper to be published later this year in the Journal of Polymer Science Part B: Polymer Physics, Wool documents a new conceptual approach, known as the Twinkling Fractal Theory (TFT), to understanding the nature and structure of the glass transition in amorphous materials. The theory provides a quantitative way of describing a phenomenon that was previously explained from a strictly empirical perspective.

“The TFT enables a number of predictions of universal behavior to be made about glassy materials of all sorts, including polymers, metals and ceramics,” Wool says.

Another difference between glasses and more conventional materials is that their transition from the liquid to the solid state does not occur at a standard temperature, like that of water to ice, but instead is rate-dependent: the more rapid the cooling, the higher the glass transition temperature.

Wool discovered that as a liquid cools toward the glassy state, the atoms form clusters that eventually become stable and percolate near the glass transition temperature. The percolating clusters are stable fractals, or structures with irregular or fragmented shapes.

“At the glass transition temperature, these fractals appear to twinkle in a specific frequency spectrum,” Wool says. “The twinkling frequencies determine the kinetics of the glass transition temperature and the dynamics of the glassy state.”

The theory has been validated by experimental results reported by Nathan Israeloff, a physics professor at Northeastern University. “He was not aware of the TFT,” Wool says, “but his results fit my theory in extraordinarily explicit detail.”

TFT was developed as an outgrowth of Wool's research on bio-based materials such as soy-based composites. “It was my need to solve issues in the development of these materials that led me to the theory,” he says.

For now, Wool is content to view the theory as a portal into materials science and solid-state physics that others can use to go in new directions. “Acceptance will come when people recognize that it works,” he says.

TFT has the potential to contribute to better understanding of such phenomena as fracture, aggregation and physical aging of materials. “It is also giving us new insights into the peculiarities of nanomaterials, which behave very differently from their macroscopic counterparts,” Wool says.

Wool, who earned his doctorate at the University of Utah, joined the UD faculty in 1995. An affiliated faculty member in the Center for Composite Materials, he was recently featured on the Sundance Channel series “Big Ideas for a Small Planet.”

Andrea Boyle | Newswise Science News
Further information:
http://www.udel.edu

Further reports about: Liquid Molecules Polymer Solid TFT Theory Twinkling Fractal Theory Wool glass glassy materials liquids transition

More articles from Life Sciences:

nachricht Water world
20.11.2017 | Washington University in St. Louis

nachricht Carefully crafted light pulses control neuron activity
20.11.2017 | University of Illinois at Urbana-Champaign

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Water world

20.11.2017 | Life Sciences

Less is more to produce top-notch 2D materials

20.11.2017 | Materials Sciences

Carefully crafted light pulses control neuron activity

20.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>