Application of chemically synthesized conducting polymer-polypyrrole as a carbon dioxide gas sensor

Deposition of Pristine and Functionalized MWCNTs in Alumina Matrix by Sol-Gel Technique and Investigation of their Ammonia Sensing Properties

“…These results support the fact that ammonia interaction with p-MWCNTs is dominated by physisorption which can easily be overcome at room temperature by nitrogen flow [9]. While ammonia interaction with f-CNTs where oxygen containing functional groups are present on CNTs surface chemisorptions is dominated and due to the strong chemical bonding chemisorbed molecules are hardly removed from CNTs upon air exposure [8][9], resulting in slow recovery of functionalized CNTs based ammonia sensors [16][17]. Hence it is clear that some external energy is needed to break the strong chemical bonds between ammonia molecule and oxygen containing groups of f-MWCNTs to achieve complete recovery.…”

Examining the use of TiO2 to enhance the NH3 sensitivity of polypyrrole films

“…In our experiments, the polymerization of pyrrole in aqueous solution, which contained a certain amount of TiO 2 particles, was directly taken on the Mylar substrate. The peel force of the typical composite film to substrate was 0.85 (60.02) N. Figure 2 gives the XRD patterns of the powder after long exposition to NH 3 weakened, and the reason is not clear now. Figure 3 shows the sensitivity of the pristine PPy and PPy/TiO 2 composite film after exposure to 100 ppm NH 3 for 300 s to investigate the sensitivity and stability of the films.…”

“…The gas sensors based on conducting polymer have received considerable interest because of their superior properties such as excellent conductivity, high gas-sensing ability, and good environment stability. [3][4][5] On the other hand, the oxide-based polymer composites have been reported to obtain the optimal properties in recent years, which exhibit high sensitivity to numerous kinds of gases including NH 3 , vapors of organic solvents and other toxic gases, and their electrical responses were believed to involve the modification of the conductive path due to the swelling of polymer film and/or the charge transfer resulting from the interaction of adsorbed gas molecules with semiconducting oxide and conducting polymers. 6,7 Among the various organic conductive polymers, polypyrrole (PPy) has been studied frequently as a gas sensor owing to its excellent properties of stability and flexibility.…”

A Study & Real Time Monitoring of Metal Oxide Semiconductor (MOS) Gas Sensor

“…On exposure to the reducing gas the resistance of the n-type sensors decreases [6] and by measuring the change in the electrical resistance, the sensitivity was calculated as [7]:-Sensitivity (S) = (R base -R gas) /R base Where, R gas is the resistance of the sensor under gas exposure and R base the resistance of the sensor under air. Same procedure was repeated for calculating the various parameters like sensitivity, selectivity, response time and recovery time etc.…”