Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New gas sensors patterned with conducting polymer

13.04.2005


An improved method for depositing nanoporous, conducting polymer films on miniaturized device features has been demonstrated by researchers at the National Institute of Standards and Technology (NIST).


These colorized scanning electron micrographs show a portion of the NIST microheater device before (left) and after (right) application of the sponge-like polyaniline coating


Images of two NIST microheater devices, each about 100 micrometers wide. On the left is a microheater coated with a conducting polymer, polyaniline, which is naturally green in color. On the right is an identical microheater with no coating.



Described in the April 6 issue of the Journal of the American Chemical Society,* the method may be useful as a general technique for reproducibly fabricating microdevices such as sensors for detecting toxic chemicals.

Unlike most polymers, conducting polymers have the electrical and optical properties of metals or semiconductors. These materials are of increasing interest in microelectronics because they are inexpensive, flexible and easy to synthesize.


Polyaniline is a particularly promising conducting polymer for microelectronics applications, but it is difficult to process because it doesn’t dissolve in most solvents. NIST researchers have circumvented this problem by dispersing nanoscale particles of polyaniline into a mild solvent.

"The beauty of the method," says NIST guest researcher Guofeng Li, "is that the polyaniline chain carries a natural positive charge." Once the particles are formed, electrostatic repulsion prevents them from clumping together. Moreover, the positively charged particles then can be manipulated and patterned on complex device structures by applying an electrical field.

The process produces a sponge-like coating that efficiently captures gaseous molecules. So far NIST researchers have demonstrated that such coatings can detect the difference between methanol and water vapor. Additional tests will be needed before the polymer devices could be used for detecting toxic gases.

NIST holds patents for previous work using microheaters coated with nanostructured tin oxide films. As the microheaters cycle through a series of temperatures, changes in electrical resistance are used to detect toxic gases at part per billion levels. Ultimately, NIST researchers hope to develop inexpensive arrays of microheater sensors coated with both polymer and inorganic oxide films optimized to identify the components of gas mixtures.

Gail Porter | EurekAlert!
Further information:
http://www.nist.gov

More articles from Power and Electrical Engineering:

nachricht Multicrystalline Silicon Solar Cell with 21.9 % Efficiency: Fraunhofer ISE Again Holds World Record
20.02.2017 | Fraunhofer-Institut für Solare Energiesysteme ISE

nachricht Six-legged robots faster than nature-inspired gait
17.02.2017 | Ecole Polytechnique Fédérale de Lausanne

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Switched-on DNA

20.02.2017 | Materials Sciences

Second cause of hidden hearing loss identified

20.02.2017 | Health and Medicine

Prospect for more effective treatment of nerve pain

20.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>