Chemiresistor Sensors Based on Conducting Polymers for Hypergolic Propellants and Acidic Vapors of Rocket Exhaust Plumes - A Review

This review covers the main applications of conducting polymers in chemiresistor sensors for sensing hazardous hypergolic liquid propellant vapors and toxic exhaust plume acidic vapors of solid rocket motors at explosive (percent), toxic and threshold limit value concentration levels. The First part is focused on vapors of NO2 and mixed oxides of nitrogen (MON-3). The Second part is focused on vapors of hydrazines such as hydrazine, monomethylhydrazine (MMH) and unsymmetrical dimethylhydrazine (UDMH). Chemiresistor sensors for toxic HCl vapors of exhaust plume of rockets and missiles are reviewed in the third part. Salient features of the sensors such as conducting mechanisms during sensing, thickness of sensing layer, factors that influence conductivity, response time, recovery time, detectable range, and minimum detectable limit are discussed in this review. Advantages and disadvantages of conducting polymer coated fabrics as novel chemiresistor sensors over inorganic substrates are also discussed.