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

Bosch Sensortec launches ideation community to foster and accelerate innovative IoT applications : Creativity hub for customers, partners, developers and makers February 18th, 2019

Exotic spiraling electrons discovered by physicists: Rutgers-led research could lead to advances in lighting and solar cells February 18th, 2019

Tracking pollen with quantum dots: A pollination biologist from Stellenbosch University in South Africa is using quantum dots to track the fate of individual pollen grains. This is breaking new ground in a field of research that has been hampered by the lack of a universal method February 17th, 2019

Super-light, super-insulating ceramic aerogel keeps the hottest temperatures at bay February 17th, 2019

Picosunís ALD encapsulation prevents electronics degradation February 15th, 2019

Physics

Exotic spiraling electrons discovered by physicists: Rutgers-led research could lead to advances in lighting and solar cells February 18th, 2019

Sound and light trapped by disorder February 8th, 2019

Chemistry

Rice U. lab adds porous envelope to aluminum plasmonics: Scientists marry gas-trapping framework to light-powered nanocatalysts February 10th, 2019

Kanazawa University research: Chirality inversion in a helical molecule at controlled speeds February 6th, 2019

CEA-Leti Builds Prototype of Next-Generation Mid-Infrared Optical Sensors for Portable Devices: Coin-size, On-chip Sensors that Combine High Performance and Low Power Consumption Presented in Paper at SPIE Photonics West 2019 February 5th, 2019

Discoveries

Exotic spiraling electrons discovered by physicists: Rutgers-led research could lead to advances in lighting and solar cells February 18th, 2019

Tracking pollen with quantum dots: A pollination biologist from Stellenbosch University in South Africa is using quantum dots to track the fate of individual pollen grains. This is breaking new ground in a field of research that has been hampered by the lack of a universal method February 17th, 2019

The smallest skeletons in the marine world observed in 3D by synchrotron techniques February 15th, 2019

Researchers create ultra-lightweight ceramic material that withstands extreme temperatures: UCLA-led team develops highly durable aerogel that could ultimately be an upgrade for insulation on spacecraft February 15th, 2019

Announcements

Bosch Sensortec launches ideation community to foster and accelerate innovative IoT applications : Creativity hub for customers, partners, developers and makers February 18th, 2019

Exotic spiraling electrons discovered by physicists: Rutgers-led research could lead to advances in lighting and solar cells February 18th, 2019

Tracking pollen with quantum dots: A pollination biologist from Stellenbosch University in South Africa is using quantum dots to track the fate of individual pollen grains. This is breaking new ground in a field of research that has been hampered by the lack of a universal method February 17th, 2019

Super-light, super-insulating ceramic aerogel keeps the hottest temperatures at bay February 17th, 2019

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



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project