Polyaniline Protonation and Deprotonation Process as the Main Mechanism for Ionic Field Effect Sensors

摘要

In this work, Polyaniline (PANI) was used as a sensing film for pH measures due to its characteristic of switching protonation states under acid and alkaline solutions. Equally produced films had their sensitivity (electric response versus pH) measured before and after being under the influence of a constant electric potential (from 3.5 to 6 V, one for each film) for the analysis on how the electric potential influenced the sensitivity. Then, the protonation caused by the application of the first potential was reversed by applying a constant 5 V reverse potential and the sensitivity was then evaluated again. The results show, on average, a constant relation between intensity of protonation and the potential applied and that the process of protonation is reversible by applying a higher opposite potential then the protonation one.