Polymer based gas sensors

POLYMER BASED GAS SENSORS^*

CELSO P. DEMELO

Departamento de Física, Centro de Ciências Exatas e da Natureza, UFPE, 50740 Recife, PE.

The electrical properties of conducting polymers samples are extremely sensitive to the environment. This property can be cleverly exploited to the development of sensors responding to the presence of even small amounts of gases and vapors. Electronic noses - i.e. devices which are able not only to indicate the presence of introduced aroma but also of identifying them in an unequivocal manner - based on the different level of response of each individual polymeric sample disposed as members of a small sensor array have been recently developed.

We discuss recent work done by our Group in Recife, where a cooperative team of physicists, chemists and computer scientists have devised new manners of preparing very thin films of conducting polymers and implemented ways of automatically collecting the fractional change in the electrical resistance of the samples and processing the input signals for the recognition of specific patterns which could be associated to the presence of simple and complex aromas.

In their successive versions, the instruments developed by our Group have been used not only to identify the presence of vapors of common organic solvents but also to analyze wines of different kinds. The degree of accuracy attained was above 90% even for the task of identifying vintages of a same type of red wine. At present, efforts are directed to the development of electronic noses which could operate as real time instruments, providing in situ analysis for different applications. The importance of such devices, for instance in the quality control in the food and beverage industry, and in the monitoring of environmental quality in the gas and oil plants, can hardly be overstated. (May 19, 2000)

^*

Financial support: CNPq, FINEP, RHAE and PADCT.

Publication Dates

• Publication in this collection
  05 Jan 2001
• Date of issue
  Dec 2000