Clean Technology 2008
D.A. Meka, L.A. George, S. Prasad
Portland State University, US
polymer nanocomposite, Chemiresistive, sensors, NOx
We present here the development of a polymer nanocomposite based gas sensor for detecting trace gas emissions in ambient environment. This project is aimed to build a chemiresistive gas sensor with excellent sensitivity and improved specificity through innovative functionalization and packaging of nanomaterial. The goal of this project is to improve sensitivity of carbon-based nanomaterial sensors from parts-per-million (ppm) levels to parts-per-billion (ppb) under real world levels of air contaminants. Emission of harmful gases into the atmosphere pollutes the environment. These gases may cause ‘acid rain’, ‘smog’ and some might be responsible for green house effect, which will affect the health of the mankind. In order to control the emission of these harmful gases we first need to detect them. The principle of operation of these chemiresistive sensors is based on the measurement of resistance change associated with the adsorption of gaseous agents by the nanomaterial matrix. These gas sensors function on the chemiresistive principle-variations in the resistance of a trace gas sensitive polymer encapsulated active sensing element comprising of carbon nanoparticles is observed due to the selective adsorption of the reactive gases. In contrast to the current techniques in gas sensing, the technique that is under development has a simple photolithography based fabrication scheme that can be executed on a non specialized wet bench, thus it is less expensive, highly reproducible and robust. For the current application, the sensor characteristics will be demonstrated for nitrogen oxides (NOx).