Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Carnegie Mellon University announces ’one-step’ method to make polymer nanowires

31.03.2004


Increases versatility of conducting polymers





A powerful one-step, "chain growth" method should make it easier to design and synthesize a variety of highly conductive polymers for different research and commercial applications, according to a presentation by the method’s developer, Carnegie Mellon University chemist Richard McCullough. McCullough, dean of the Mellon College of Science and professor of chemistry, is reporting his research Tuesday, March 30, at the 227th annual meeting of the American Chemical Society in Anaheim, Calif. (POLY 360, Plaza B).

McCullough has harnessed the chain-growth method to increase the versatility of the conducting polymers, called regioregular polythiophenes. This new method allows scientists to "cap" each conducting polymer with chemical groups that link to other structural polymers (Figure 1). With this research, funded by the National Science Foundation, researchers can form highly conductive nanowire sheets within polymer blocks (Figure 2) or create a plethora of new conducting polymers.


Variations in the chemical "cap" also allow regioregular polythiophene strands to adhere directly to metal, silicon or other industrially important templates used in devices like transistors (Figure 3). They effectively self-assemble into a well-ordered, highly conducting nanoscale layers.

"The chain-growth method eliminates six production steps to create block co-polymer nanowires that conduct electricity a million times better than the all other conducting block copolymers," said McCullough.

Conducting polymers are remarkable materials that possess the electrical properties of metals yet retain the mechanical properties of polymers. In 1992 McCullough was the first to report the synthesis of regioregular polythiophenes, which in 2002 became the basis of a Carnegie Mellon spinout company, Plextronics, Inc.

The current research was conducted, in large part, by postdoctoral research fellows Malika Jeffries-El and Genevieve Sauve.

Block copolymers of regioregular polythiophenes conduct electricity so well due to their uniform composition and neat alignment into nanowires. Impurities and random orientation of polymer strands created by other methods vastly reduces their ability to conduct electricity, according to McCullough.

"A good analogy is a water hose. A bent hose transports water poorly, whereas a straight hose conducts water much more effectively. Likewise, irregularly shaped, disorganized polymers are poor conductors of electricity, whereas straight, stackable regioregular polythiophenes are excellent electrical conductors," said McCullough.

Regioregular polythiophenes have a wide range of potential applications, such as dissipating static electrical charges that build up on coated floors or use in disposable devices called radio frequency identification tags. (See www.plextronics.com for additional applications).

The superior conducting performance of regioregular polythiophenes is captured in their structure. Each polymer unit is composed of a chemical ring (thiophene) with a chemical branch on one side. Units are attached head to tail, so that all of the branches line up in one direction, much like feathers (Figure 4). The head-to-tail structure effectively straightens polythiophenes into rods that can be stacked one atop another.

To make a regioregular polythiophene polymer conductive, the scientists incorporate a pinch of a reactive additive to the polymer. This step removes some electrons from the forming polymer, thereby freeing the remaining electrons to move up and down the final polymer.

By attaching normal plastics to the polythiophene backbone, McCullough’s team can create nanowire stacks with versatile properties, such as softness and solubility in different fluids used in industrial manufacturing. Because their properties can be varied, regioregular conducting polymers have the widest range of commercial applications compared with any other conducting polymer, he said.


The Mellon College of Science at Carnegie Mellon University maintains innovative research and educational programs in biological sciences, chemistry, physics, mathematics and several interdisciplinary areas. For more information, visit http://www.cmu.edu/mcs.

Plextronics takes advantage of the vast commercial opportunities generated by these breakthroughs and has designed a new generation of matrials that enable broad market potential. For more information about Plextronics, Inc., please contact Jennifer Honig at jhonig@plextronics.com or 412-977-7703.

Lauren Ward | EurekAlert!
Further information:
http://www.cmu.edu/

More articles from Materials Sciences:

nachricht Modified 'white graphene' for eco-friendly energy
23.04.2019 | Tomsk Polytechnic University

nachricht New method inverts the self-assembly of liquid crystals
15.04.2019 | University of Luxembourg

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Quantum gas turns supersolid

Researchers led by Francesca Ferlaino from the University of Innsbruck and the Austrian Academy of Sciences report in Physical Review X on the observation of supersolid behavior in dipolar quantum gases of erbium and dysprosium. In the dysprosium gas these properties are unprecedentedly long-lived. This sets the stage for future investigations into the nature of this exotic phase of matter.

Supersolidity is a paradoxical state where the matter is both crystallized and superfluid. Predicted 50 years ago, such a counter-intuitive phase, featuring...

Im Focus: Explosion on Jupiter-sized star 10 times more powerful than ever seen on our sun

A stellar flare 10 times more powerful than anything seen on our sun has burst from an ultracool star almost the same size as Jupiter

  • Coolest and smallest star to produce a superflare found
  • Star is a tenth of the radius of our Sun
  • Researchers led by University of Warwick could only see...

Im Focus: Quantum simulation more stable than expected

A localization phenomenon boosts the accuracy of solving quantum many-body problems with quantum computers which are otherwise challenging for conventional computers. This brings such digital quantum simulation within reach on quantum devices available today.

Quantum computers promise to solve certain computational problems exponentially faster than any classical machine. “A particularly promising application is the...

Im Focus: Largest, fastest array of microscopic 'traffic cops' for optical communications

The technology could revolutionize how information travels through data centers and artificial intelligence networks

Engineers at the University of California, Berkeley have built a new photonic switch that can control the direction of light passing through optical fibers...

Im Focus: A long-distance relationship in femtoseconds

Physicists observe how electron-hole pairs drift apart at ultrafast speed, but still remain strongly bound.

Modern electronics relies on ultrafast charge motion on ever shorter length scales. Physicists from Regensburg and Gothenburg have now succeeded in resolving a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

Fraunhofer FHR at the IEEE Radar Conference 2019 in Boston, USA

09.04.2019 | Event News

 
Latest News

Control 2019: Fraunhofer IPT presents high-speed microscope with intuitive gesture control

24.04.2019 | Trade Fair News

Marine Skin dives deeper for better monitoring

23.04.2019 | Information Technology

Geomagnetic jerks finally reproduced and explained

23.04.2019 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>