PANI/PPY blend thin films electrodeposited for use in EGFET sensors

Abstract

ABSTRACTGalvanostatic electrodeposited thin films of polyaniline (PANI)/polypyrrole (PPY) blend were tested as chemical sensors and evaluated according to the relative monomer concentration in polymerization solution aiming to obtain a reliable reference field‐effect transistor able to be used as contrast sensing film. The blend material presented properties that can be controlled by the polymerization process. The films were produced using aniline (0.25 M) and pyrrole (0.25 M) mixed in five different proportions (90/10, 70/30, 50/50, 30/70, 10/90) with HCl (1.0 M) in an aqueous solution. The current density was 1 mA/cm2 for 300 s. The films were analyzed by their chronopotentiometric curves, thickness, reflectance spectroscopy, optical color parameters, and surface morphology. The characteristics and properties analyzed were correlated to the relative monomer concentration in the polymerization solution. The polymerization of PANI is favorable in aqueous acid solution compared to PPY, which resulted in thin films with properties varying from PANI down to PPY. The blend films presented controllable sensitivity when applied as sensing stage in field‐effect transistor devices as function of the relative monomer concentration. The sensitivity varied from 57 ± 1 mV/pH for the PANI sample, down to 25 ± 1 mV/pH for the PPY sample, presenting an exponential behavior. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46625.