Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Temperature-sensitive Nanobrushes

Abstract:
Electrically conducting polymer with temperature-dependent optical properties and water solubility

Temperature-sensitive Nanobrushes

July 13, 2005

The terms plastic and electrical current usually bring to mind such things as insulators or computer cases. It goes without saying that plastics are insulators, right? The discovery of conducting polymers actually resulted in a Nobel Prize in Chemistry for A.J. Heeger, A.G. MacDiarmid and H. Shirakawa in 2000 - "plastic electronics" are on the move. An American team has now developed a conducting polythiophene that demonstrates amazingly high water solubility and responds to the surrounding temperature as well.

Why the interest in electrically conducting polymers that are water-soluble? Water solubility allows for more environmentally friendly production processes. In addition, it is a requirement for many biological and diagnostic applications. Certain conducting polymers also respond to changes in their environment by a color change. This is just the thing for sensors that detect specific analyte molecules or indicate other parameters.

Polythiophenes, the most economically important class of conducting polymers, consist of long chains of five-membered rings containing four carbon atoms and one sulfur atom. Researchers led by Robin L. McCarley at Louisiana State University attached chains of a polyacrylamide derivative to a polythiophene backbone like bristles on the handle of a bottle brush. The "bristles" make the molecular "brushes" the most water-soluble neutral polythiophenes found to date.

But these bristles can do more: they respond sensitively to temperature changes. At temperatures under 30 °C, the brushes are in an irregular, stretched-out form and are loaded with water molecules. If the temperature is raised above 32 °C, these structures collapse into compact spheres, pushing the water molecules out. As a result, the entire brush responds to the conformational change of its bristles. From a stretched-out, only slightly balled-up form, it pulls itself into a compact spherical structure. This change decreases the water solubility of the brushes. More significantly, at the same time, the color changes; whereas a solution of the brushes at low temperature is orange-red in appearance, higher temperatures cause the color to change to yellow. This change in color indicates shifts in the electrical properties of the backbone.

Such water-soluble polymeric brushes, which react to external stimulation by changing their opto-electronic properties, could be used for biosensors in bioelectronics, as nanoswitches, light-emitting diodes, or fluorescence thermometers.

Author: Robin L. McCarley, Louisiana State University, Baton Rouge (USA),

####

Contact:
Editorial office
angewandte@wiley-vch.de

David Greenberg (US)
dgreenbe@wiley.com

Julia Lampam (UK)
jlampam@wiley.co.uk

Copyright © Angewandte Chemie

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

Possible Futures

New low-cost technique converts bulk alloys to oxide nanowires January 24th, 2017

Harris & Harris Group Announces the Filing of Preliminary Proxy Materials Detailing Its Proposed Conversion From a BDC to a Registered Closed-End Fund January 24th, 2017

The speed limit for intra-chip communications in microprocessors of the future January 23rd, 2017

New, old science combine to make faster medical test: Nanoparticles and Faraday rotation allow faster diagnoses January 23rd, 2017

Sensors

New research helps to meet the challenges of nanotechnology: Research helps to make the most of nanoscale catalytic effects for nanotechnology January 20th, 2017

Ultra-precise chip-scale sensor detects unprecedentedly small changes at the nanoscale January 20th, 2017

Chemists Cook up New Nanomaterial and Imaging Method: Nanomaterials can store all kinds of things, including energy, drugs and other cargo January 19th, 2017

Nanoscale Modifications can be used to Engineer Electrical Contacts for Nanodevices January 13th, 2017

Announcements

Bruker Announces Acquisition of Nanoindenting Leader Hysitron: Acquisition strengthens Bruker’s leading position in nanoanalysis and nanomechanical materials characterization January 24th, 2017

New low-cost technique converts bulk alloys to oxide nanowires January 24th, 2017

News from Quorum: Experienced electron microscopist, David McCarthy, talks about working with Quorum and his use of their coaters and cryo-SEM preparation instrumentation January 24th, 2017

Tough aqua material for water purification: Decontamination of water with a robust and sustainable membrane assembled from 2 synergistically working components January 24th, 2017

Environment

Investigating the impact of natural and manmade nanomaterials on living things: Center for Environmental Implications of Nanotechnology develops tools to assess current and future risk January 9th, 2017

PCATDES Starts Field Testing of Photocatalytic Reactors in South East Asia December 28th, 2016

Advance in intense pulsed light sintering opens door to improved electronics manufacturing December 23rd, 2016

Carbon dots dash toward 'green' recycling role: Rice scientists, colleagues use doped graphene quantum dots to reduce carbon dioxide to fuel December 18th, 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