Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

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

Designing ultrasound tools with Lego-like proteins August 29th, 2016

A nanoscale wireless communication system via plasmonic antennas: Greater control affords 'in-plane' transmission of waves at or near visible light August 27th, 2016

Forces of nature: Interview with microscopy innovators Gerd Binnig and Christoph Gerber August 26th, 2016

A promising route to the scalable production of highly crystalline graphene films August 26th, 2016

Physics

Graphene under pressure August 26th, 2016

Silicon nanoparticles trained to juggle light: Research findings prove the capabilities of silicon nanoparticles for flexible data processing in optical communication systems August 25th, 2016

New approach to determining how atoms are arranged in materials August 25th, 2016

Unraveling the crystal structure of a -70 Celsius superconductor, a world first: Significant advancement in the realization of room-temperature superconductors August 25th, 2016

Chemistry

A new way to display the 3-D structure of molecules: Metal-organic frameworks provide a new platform for solving the structure of hard-to-study samples August 21st, 2016

Researchers watch catalysts at work August 19th, 2016

Pokhara, the second largest city of Nepal, to host its first ever International Meeting on Material Sciences and Engineering August 15th, 2016

'Liquid fingerprinting' technique instantly identifies unknown liquids: Ability to instantly identify unknown liquids in the field could aid first responders, improve plant safety August 4th, 2016

Discoveries

Designing ultrasound tools with Lego-like proteins August 29th, 2016

A promising route to the scalable production of highly crystalline graphene films August 26th, 2016

Graphene under pressure August 26th, 2016

New electrical energy storage material shows its power: Nanomaterial combines attributes of both batteries and supercapacitors August 25th, 2016

Announcements

Designing ultrasound tools with Lego-like proteins August 29th, 2016

A nanoscale wireless communication system via plasmonic antennas: Greater control affords 'in-plane' transmission of waves at or near visible light August 27th, 2016

Forces of nature: Interview with microscopy innovators Gerd Binnig and Christoph Gerber August 26th, 2016

A promising route to the scalable production of highly crystalline graphene films August 26th, 2016

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







Car Brands
Buy website traffic