Navigation Links
Understanding how glasses 'relax' provides some relief for manufacturers
Date:4/27/2011

Manufacturers who design new materials often struggle to understand viscous liquids at a molecular scale. Many substances including polymers and biological materials change upon cooling from a watery state at elevated temperatures to a tar-like consistency at intermediate temperatures, then become a solid "glass" similar to hard candy at lower temperatures. Scientists have long sought a molecular-level description of this theoretically mysterious, yet common, "glass transition" process as an alternative to expensive and time-consuming trial-and-error material discovery methods. Such a description might permit the better design of plastics and containers that could lengthen the shelf life of food and drugs.

A fundamental question is why many materials behave differently when temperature changes. In some "fragile" glass-forming materials, a modest variation in temperature can make the material change from highly fluid to extremely viscous, while in "strong" fluids this change in viscosity is much more gradual. This effect influences how long a manufacturer has to work with a material as it cools. "For decades, material scientists have heavily relied on empirical rules of thumb to characterize these materials," says NIST theoretician Jack Douglas. "But if you want to design a material that does precisely what you want, you need a molecular understanding of the underlying physical processes involved."

According to Douglas, the increasingly viscous nature of glass-forming liquids is related to molecules that move together in long strings around other atoms that are almost frozen in their motion. The growth of these snake-like structures leads to an increase in the viscosity of the liquid: the lower the temperature, the longer the chains, and the more viscous the fluid. The team found that the rate at which these spontaneously organizing snake-like strings grow in size as the material cools is quantitatively related mathematically to the fluid fragilityconfirming intuitive arguments made nearly half a century ago by physicists G. Adams and J.H. Gibbs, but now bolstering them with a firm computational underpinning.

Douglas and his collaborator Francis Starr of Wesleyan University achieved a large variation of fluid fragility through use of a computer model, which mimics a polymer fluid that includes tiny nanometer-sized particles. Portraying the addition of various amounts of nanoparticles and varying their interaction with the polymers, Starr says, gave the team a sort of "knob to tweak" to reveal how the fluidity changed with temperature and how the motion of the clusters was quantitatively related to changes in the fluid's properties. This tuning of cooperative motion in glass-forming liquids and fragility should be crucial in material design. Douglas says.


'/>"/>

Contact: Chad Boutin
boutin@nist.gov
301-975-4261
National Institute of Standards and Technology (NIST)
Source:Eurekalert

Related biology technology :

1. Understanding the science of solar-based energy: more researchers are better than one
2. Immtech and Beijing Pharmaceutical Group Co. Sign Memorandum of Understanding to Explore Developing Strategic Business Alliance
3. New Survey Reveals Gap in Understanding of Alzheimers Disease Risk and Prevention Among Most Vulnerable Populations
4. Campaign to Increase the Awareness and Understanding of Lou Gehrigs Disease Reaches 22 U.S. States
5. Understanding Managed Markets: Effective Market Research Structures & Activities to Maximize Payer Access & Insights
6. ISMPP Supports Best Practices and Transparency in Medical Publications: Better Understanding of Terms Such as Ghostwriting Needed
7. Understanding mechanical properties of silicon nanowires paves way for nanodevices
8. Matrix Corporate Capital and PharmaVentures Announce the Signing of a Memorandum of Understanding (MOU)
9. Songbird genome to aid understanding of learning, memory and more
10. Improve Chemistry Understanding with Reaction Analysis
11. CBR Pharma Insights' Latest Report, The New Era of Healthcare Reform - Supporting Revenue Growth through Understanding & Adaptation
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/22/2017)... , March 22, 2017 /PRNewswire/ - FACIT announced ... "Company" or "Propellon"), a start-up created by FACIT ... therapeutics. FACIT,s investment, combined with non-dilutive capital, achieves ... The seed funding enables Propellon to accelerate the ... Company for financing and/or entering a strategic partnership ...
(Date:3/22/2017)... ... ... executive recruitment firm, Slone Partners, is proud to have been named a Top 50 ... Scanlon Media is one of the most respected life science publications in the United ... , “It is a great honor for Slone Partners to be part of this ...
(Date:3/22/2017)... ... March 21, 2017 , ... Benchworks CEO ... Executive Officer Forum on March 23-24 in San Diego. The event is a ... diagnostic industries. , Benchworks Vice President Christian Meyer will also participate in the ...
(Date:3/22/2017)... ... March 21, 2017 , ... ... has unveiled its innovative Quantum peristaltic pump with patented ReNu single-use (SU) ... the new standard for high-pressure feed pumps in SU tangential flow filtration ...
Breaking Biology Technology:
(Date:3/2/2017)... Who risk to be deprived of its ... report: https://www.reportbuyer.com/product/4313699/ WILL APPLE AND SAMSUNG ... Fingerprint sensors using capacitive technology represent a fast growing ... forecasts an increase of 360% of the number of ... fingerprint sensor market between 2014 and 2017 (source : ...
(Date:3/1/2017)... 2017  Aware, Inc. (NASDAQ: AWRE), a leading supplier ... P. Moberg has resigned, effective March 3, 2017, ... Officer and Treasurer of Aware citing a desire to ... member of the Board of Directors of Aware. ... Officer and co-President, General Counsel has been named Chief ...
(Date:2/28/2017)... February 28, 2017 News solutions for biometrics, ... ... from 14 to 16 March, Materna will present its ... how seamless travel is a real benefit for passengers. To ... to their passenger touch point solutions to take passengers through the ...
Breaking Biology News(10 mins):