Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Nanostructures switch faster

Abstract:
The reaction time of Polymer chains of approximately 100 nanometers in length was thought to be too slow, but a researcher at the University of Duisburg-Essen has disproven that.

Nanostructures switch faster

Germany | Posted on June 22nd, 2011

To describe them as microscopically small would be an understatement, yet they could play a big role in future technology: Polymer chains of approximately 100 nanometers in length could operate as tiny switches in advanced applications. In the past, the reaction time of such nanostructures was thought to be too slow, but a research group at the University of Duisburg-Essen (UDE) under the direction of Dr. Nils Hartmann at the Center for Nanointegration (CeNIDE) has disproven this theory, and their results have been published in the international journal "Angewandte Chemie" (Vol. 123, No. 19).

The polymer Poly(N-Isopropylacrylamide) can also be found in a modified form in diapers. This material keeps the baby's bottom dry by wicking away the moisture˜for that reason it is classified as a "hydrogel". Prof. Dr. Mathias Ulbricht, who holds a Chair in Technical Chemistry at CeNIDE, established routines which allow one to firmly attach such polymer chains to a surface. At temperatures below 32°C the layers absorb water and the structure resembles a brush. When the temperature rises above the critical point, the tiny chains collapse and form dense layers. Depending on the structure, the thickness of the layers decreases by at least one half. In this way, the material could be used to regulate valves in small openings and channels, such as those used in membrane technology or microfluidics. It could be used to measure temperature or moisture, control the release of drugs within the human body, or work as a miniaturized switch for many other processes. With the aid of nanopolymers, small structures could also be created that would react much more quickly than their macroscopic counterparts. According to theory, the water needed for the structural changes would have to travel a shorter diffusion path; however, in many applications speed proved to remain a problem. Repeated tests showed reaction times on the order of seconds˜much too slow for high speed applications.

Dr. Nils Hartmann is group leader at the Chair of Physical Chemistry and a member of CeNIDE. He recognized the primary hurdle in previous experiments: In order to measure the rate of the process, a characterization method is required that is faster than the process itself as well as a manipulation tool that will immediately cause the reaction of the polymer. Hartmann explains that, "The overall technique must be well adapted to the switching process, otherwise itself will cause a delayed reaction of the material." At least one of these two issues have not been recognized in previous research.

Hartmann's team developed a new stroboscopic method whereby the researchers heat the substrate/polymer interface with a laser. When the laser is on, the polymer becomes hot instantaneously; when it is off, the heat dissipates immediately. In order to observe the switching process, an optical microscope with a CCD camera was used. During stroboscopic measurements each frame captured a slightly delayed time interval of the heating and cooling phases. Within 16 seconds this method was able to completely measure the temperature-dependent kinetics. The results revealed that the hydrogel reacts within micro- or milliseconds to the laser-induced change of temperature. Hartmann happily remarked, "This alone is a completely new discovery, but we can also demonstrate that the polymer is not damaged, even after thousands of repetitions, so it is suitable for long-term use."

Other experts also regard these discoveries as extremely significant, which is demonstrated by its publication as a "VIP Paper" in the esteemed journal of "Angewandte Chemie."

Angewandte Chemie (2011) Vol. 123: 4606 - 4609
Angewandte Chemie International Edition (2011) Vol. 50: 4513 ˆ 4516

####

For more information, please click here

Contacts:
Birte Vierjahn

Copyright © CeNIDE, University of Duisburg-Essen

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

Haydale Secures Exclusive Development and Supply Agreement with Tantec A/S: New reactors to be built and commissioned by Tantec A/S represent another step forward towards the commercialisation of graphene October 24th, 2014

QuantumWise guides the semiconductor industry towards the atomic scale October 24th, 2014

MEMS & Sensors Technology Showcase: Finalists Announced for MEMS Executive Congress US 2014 October 23rd, 2014

Nanoparticle technology triples the production of biogas October 23rd, 2014

Discoveries

QuantumWise guides the semiconductor industry towards the atomic scale October 24th, 2014

Iranian, Malaysian Scientists Study Nanophotocatalysts for Water Purification October 23rd, 2014

Nanoparticle technology triples the production of biogas October 23rd, 2014

Strengthening thin-film bonds with ultrafast data collection October 23rd, 2014

Materials/Metamaterials

Researchers patent a nanofluid that improves heat conductivity October 22nd, 2014

Materials for the next generation of electronics and photovoltaics: MacArthur Fellow develops new uses for carbon nanotubes October 21st, 2014

Super stable garnet ceramics may be ideal for high-energy lithium batteries October 21st, 2014

Could I squeeze by you? Ames Laboratory scientists model molecular movement within narrow channels of mesoporous nanoparticles October 21st, 2014

Announcements

Haydale Secures Exclusive Development and Supply Agreement with Tantec A/S: New reactors to be built and commissioned by Tantec A/S represent another step forward towards the commercialisation of graphene October 24th, 2014

QuantumWise guides the semiconductor industry towards the atomic scale October 24th, 2014

Advancing thin film research with nanostructured AZO: Innovnano’s unique and cost-effective AZO sputtering targets for the production of transparent conducting oxides October 23rd, 2014

Strengthening thin-film bonds with ultrafast data collection October 23rd, 2014

Photonics/Optics/Lasers

Physicists build reversible laser tractor beam October 20th, 2014

Magnetic mirrors enable new technologies by reflecting light in uncanny ways October 16th, 2014

New VDMA Association "Electronics, Micro and Nano Technologies" founded: Inaugural Meeting in Frankfurt/Main, Germany October 15th, 2014

Nanodevices for clinical diagnostic with potential for the international market: The development is based on optical principles and provides precision and allows saving vital time for the patient October 15th, 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