Using Electrospinning for the Fabrication of Rapid Response Gas Sensors Based on Conducting Polymer Nanowires

Abstract

Early detection of trace amounts of toxic gases in an open environment is vital for any successful attempt to contain subsequent damage. The sensors used must respond quickly and reliably in such a situation. A typical method to increase sensitivity is to use sensors that have a large exposed area. It is also desirable for the sensor to be small in size and to consume low power. These characteristics can easily be achieved via the use of conducting polymer nanowires. Polyaniline is such a conducting polymer whose conductivity can be tuned to any desirable value in the range 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-8</sup> S/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-10</sup> S/cm. We have prepared nanowires of this polymer in air and within seconds of using the electrospinning technique and used them in the fabrication of gas sensors. Due to the large surface-to-volume ratio and small amount of active material used, these sensors are faster and more reliable than conventional sensors based on thin films. While several methods exist to prepare polymer nanowires, most yield short (typically a few microns long) nanowires with tedious methods of isolating a single one. Electrospinning is a simple technique for making long (typically several centimeters long) nanowires that can easily be isolated and therefore is a promising method for the fabrication of low cost rapid response sensors.