ABSTRACT
The conducting polymers used for these experiments were poly(pyrro1e)l butane sulfonic acid, sodium salt (BSA) and poly(bithiophene)/tetrabutylammonium tetrafluoroborate (TFBTFA), deposited at the Department of Chemistry, University of Southampton, UK. The gold gates of the FET were cleaned using cyclic voltammetries in 1 rnol dm" sulphuric acid. This was carried out by employing a micro-deposition technique in which a luggin capillary and counter wire were combined into a single structure [5]. This technique was modified by adding an adjoining arm to the luggin capillary from which the level of solution, hence the height of solution above the device, can be adjusted. Thus the pressure exerted by the solution above the device was controlled. This modification was necessaw when the solution used was acetonitrile which has a lower surface tension than water, and tends to flow out of the luggin capillary. The luggin capillary was filled with 1 rnol dm" sulphuric acid and connected to a double-frit SCE reference electrode. A column of electrolytic solution, maintained by its surface tension, from the luggin capillary was then carefully positioned over the centre sensing area of the PolyFET device using the xyz translator of the microstage.
