Study of the action of gases on a polypyrrole film

Abstract D.c. conductivity measurements are performed on PPy films initially doped with Fe(CN) 6 4− , then exposed to diluted O 2 , NH 3 , NO 2 in N 2 or air. By working at 100 °C and after a stabilizing treatment, some NH 3 sensor ability is found for high concentrations, but this requires the measurement of very low currents. The doping kinetics are analysed as both Elovich superficial adsorption and diffusion in the bulk. A poisoning effect of NO 2 is observed, and afterwards the possibility of 'n' doping as by NH 3 is demonstrated.