The use of conducting polymer sensors for environmental monitoring

This thesis details the development of conducting polymer (CP) sensors, and associated devices for monitoring chemical species of environmental significance. A key aspect of this work was the fabrication and testing of novel CP gas sensors, based on inexpensive polymer substrates with screen-printed carbon electrodes. These devices were used in electronic nose systems for the identification and discrimination of organic vapours, and on a small autonomous robot to detect, track and locate the source of ammonia vapour plumes. The possibility of modifying chemically deposited Polypyrrole (PPy) thin films post-polymerisation using solution based anion exchange methods was evaluated, in an attempt to alter chemical selectivity whilst retaining the sensitivity of such devices. Approaches to reducing the humidity response of PPy gas sensors, a significant interferant when sensing many sample matrices, were also examined with the view to developing vapour detection systems for organic volatiles in water. A comprehensive study of the electrochemistry and spectral properties of a water soluble conducting polymer, Polymethoxyaniline sulfonate (PMAS), and the effect of molecular weight on these properties was undertaken. This work was carried out in order to better understand the mechanism of interaction between PMAS and the microorganism Listeria Monocytogenes, which is under development at IPRI as a detection system for this species.