Testing the Chemical Sensors Based on Poly pyrrole

5 Testing the Chemical Sensors Based on Poly(pyrrole) 

Both gas sensors based on nontemplated and nanostructured PPy films were found to respond to a variety of solvent vapors, including methanol, ethanol, isopropanol, acetone, and also to humidity with a resistance increase. Initial tests were performed in ambient air leading to the observation of the following phenomenon, the sensors responded to water vapor with an immediate resistance increase, while exposure to organic solvents led to an initial small decrease in resistance before showing the 

The response speed, associated with the adsorption of vapor molecules on free sites in the PPy films, was typically found to be faster than the recovery speed, consisting of the desorption and evaporation of the analyte molecules from the occupied sensing sites, see Fig. 7.10a. This became especially evident in nontemplated films. On average the response time of nontemplated and DG-structured films on exposure to solvent vapors was similar, but on purging with nitrogen the structured films outperformed the nontemplated deposits, see Fig. 7.10a. Curiously, the response times varied very little with different vapor concentrations. 

Nontemplated 1 Nontemplated 2 Double-gyroid 1 Double-gyroid 2 

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