Year

2002

Degree Name

Doctor of Philosophy

Department

Department of Chemistry

Abstract

The aim of this thesis is to implement a comprehensive study of conducting polymer sensor array for detection of species in both liquid and gas phase. The research area includes design of the sensor array configuration, development of conducting polymer sensors and carrying out some applications.

Sensor configurations have been designed towards different applications using inexpensive substrate materials such as polyvinylchloride with screen printed carbon electrodes (C/PVC), transparencies, glossy papers and photo films. Conducting polymer films were then deposited onto the base electrodes to form sensor arrays. Different fabrication processes involving chemical deposition, electrochemical deposition, inkjet and contact printing were applied for each type of sensor in order to achieve the most effective CP sensor array in terms of analytical performance as well as production procedure.

For amperometric detection of species in solution, an eight C/PVC electrode array was produced using screen-printing method. Conducting polymers were electrochemically deposited onto individual carbon electrode to form the array. Of many polypyrrole based CP sensors studied, eight sensors with the best performance were selected to produce sensor array for detection of species. The obtained results indicated that the eight CP sensors array could be used to detect and discriminate between four electroinactive cations, namely, Na+, K+, Ca2+ and Mg2+, using pulsed amperometry and pattern recognition techniques.

For vapour detection, base electrode was designed containing four carbon tracks screen printed onto PVC substrate (C/PVC). Sensor arrays were formed from individual sensors and tested for discrimination of vapours from common solvents. The effect of substrates onto CP sensor performance was studied by comparison between performances of conducting polymer sensors produced from different substrates. The inexpensive C/PVC based CP sensors exhibit reasonable good performance compared with other types of sensors made of gold and quartz crystal. A concept of hybridmodules, multisubstrate CP sensor array with improved performance was also demonstrated.

Conducting polymer based sensors for humidity were produced using substrate made of polyester film sputter coated with platinum. Sensor fabrication process involves inkjet printing technology and water-soluble conducting polymers. The sensor made of poly(2-methoxyaniline-5-sulfonate) (PMAS), inkjet printed on a polyester substrate, expressed linear response to humidity in the range of 10 to 85 percent.

A mobile chemical sensing robot equipped with polyaniline based sensors was constructed. CP sensors were produced by contacting printing of polyaniline onto C/PVC substrate. The obtained results show that mobile chemical sensing robot can track down ammonia trail on the ground and locate ammonia source in air borne plume.

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