Potentiometric miniaturized pH sensors based on polypyrrole films

Potentiometric pH miniaturized sensors based on electrosynthesized polypyrrole films were developped. These pH sensors consist in two interdigitated microarray electrodes which were fabricated using photolithography process. One electrode of the sensor is coated by a polypyrrole film while the other one is coated by a silver film used as reference electrode. The potentiometric responses of these sensors were generally linear to pH changes in the range from 2 to 11. More, some sensors appeared to be stable in time during 30 days. The effect of the thickness of polymer film to potentiometric responses was also studied. It appeared that thinner polypyrrole films gave better potentiometric responses than thicker ones.