Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Relaxation dynamics of 2D nanoparticle systems

Abstract:
Soft matters maintain their structures via weak interactions, such as Van der Waals, capillary, hydrogen bonds etc. The entropy plays a key role in the ordering of this kind of materials. They behave as a solid until a sufficiently large stress is applied, and then behave as a viscoelastic liquid. Due to the unique structures and rheological properties, soft matter such as concentrated suspensions, emulsions, pastes and gels often exhibit unusual slow relaxation and aging effect. Studying the relaxation dynamics may gain more insight into the microstructure of the material and may also shed light on the understanding of the physical origin of glass transition.

Relaxation dynamics of 2D nanoparticle systems

PR China | Posted on October 24th, 2011

Nanoparticle can be trapped at the air-water interface. The formed layer is a typical 2D soft matter, which plays essential role in foams, emulsification and pharmacy. However, owing to the low dimension and absence of theory, the study of 2D relaxation is quite a challenge. By using the Langmuir troughs technique and oscillating bubbles or drops methods, a deformation can be exerted on the layer rapidly. The relaxation then can be studied by monitoring the time viaration of the surface pressure. However, these techniques can not obtain the anisotropy of the layers and hence are limited.

Dr. ZANG Duyang et al from the Key Laboratory of Space Applied Physics and Chemistry of Ministry of Education, School of Science, Northwestern Polytechnical University, has developed a novel approach in which two orthogonal Wilhelmy plates have been utilized to measure the surface pressure in the two directions. By comparing the relaxation dynamics under static and oscillation state, the relaxation mechanisms have been elucidated.

Unlike the surfactant of low molecular weight, the adsorption of nanoparticles at the interfaces is irreversible. This leads to the different Π-Γ isotherms. With the increase of surface density, as well as the textual change, the surface pressure present remarkable anisotropic effect. The anisotropy suggests that the layer is under non-equilibrium state. The relaxation towards equilibrium occurs by means of particle rearrangement. When the layer is kept static, the particle rearrangement is driven by the inner stress stored in the layer. Thus, the relaxation is slow. While under barrier oscillation, additional driving force is exerted by the barriers. Consequently, the relaxation is accelerated significantly.

This work is supported by the Northwestern Polytechnical University Foundation for Fundamental Research (NPU-FFR-JC20100242).

See the article: Zang D Y, Zhang Y J. Surface pressure anisotropy and complex relaxation of silica nanoparticle monolayer at the air-water interface. Sci China Phys Mech Astro, 2011, 41(9)

####

For more information, please click here

Contacts:
ZANG Duyang

0086-298-843-1618

Copyright © Science in China Press

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

MRI, on a molecular scale: Researchers develop system that could one day peer into the atomic structure of individual molecules April 20th, 2014

Iranian Researchers Present New Model to Strengthen Superconductivity at Higher Temperatures April 19th, 2014

Iranian Researchers Produce New Anti-Cancer Drug from Turmeric April 19th, 2014

Innovative strategy to facilitate organ repair April 18th, 2014

Physics

Thinnest feasible membrane produced April 17th, 2014

Scientists Capture Ultrafast Snapshots of Light-Driven Superconductivity: X-rays reveal how rapidly vanishing 'charge stripes' may be behind laser-induced high-temperature superconductivity April 16th, 2014

Quantum manipulation: Filling the gap between quantum and classical world April 14th, 2014

Chemistry

Thinnest feasible membrane produced April 17th, 2014

Targeting cancer with a triple threat: MIT chemists design nanoparticles that can deliver three cancer drugs at a time April 15th, 2014

Discoveries

MRI, on a molecular scale: Researchers develop system that could one day peer into the atomic structure of individual molecules April 20th, 2014

Iranian Researchers Present New Model to Strengthen Superconductivity at Higher Temperatures April 19th, 2014

Iranian Researchers Produce New Anti-Cancer Drug from Turmeric April 19th, 2014

'Exotic' material is like a switch when super thin April 18th, 2014

Announcements

MRI, on a molecular scale: Researchers develop system that could one day peer into the atomic structure of individual molecules April 20th, 2014

Iranian Researchers Present New Model to Strengthen Superconductivity at Higher Temperatures April 19th, 2014

Iranian Researchers Produce New Anti-Cancer Drug from Turmeric April 19th, 2014

Innovative strategy to facilitate organ repair April 18th, 2014

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







  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE