Alcohol Sensibility of One-Dimensional Polyaniline and Polypyrrole Nanostructures

This paper addresses the preparation of one-dimensional nanostructured polyaniline (PANI) and polypyrrole (PPy). The Fourier transform infrared spectroscopy was used to characterize the chemical structure of the samples. The morphology of the samples was investigated by scanning electron microscopy and transmission electron microscopy. A nanofibrillar morphology was observed for the synthesized PANI and a nanotubular structure was obtained in the case of PPy. The alcohol sensing behaviors of PANI and PPy nanostructures were investigated for methanol, ethanol, propanol, and butanol, and the sensing mechanism of these systems has been discussed in detail. Both PANI and PPy systems were capable of detecting very low alcohols concentration (as low as 3 ppm) and demonstrated a linear behavior with a fast response/recovery performance especially in the case of ethanol vapor. The PPy-based sensor showed a better cyclability in response as compared with PANI when exposed to ethanol atmosphere. The surface characteristics of the PANI and PPy sensitive layers were investigated via atomic force microscopy. Ultraviolet-visible spectroscopy was used to study the effect of alcohol exposure on the electronic transport properties of nanostructured PANI and PPy layers.