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

Abstract

Galvanostatic 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.

Electrochemically activated polyaniline based ambipolar organic electrochemical transistor

“…The achievement of ambipolar OECTs depends on the development of appropriate semiconducting materials which has the need of presenting both stability in an aqueous environment and reversible redox reaction, oxidation and reduction, for electrochemical doping/dedoping of the semiconducting layer in the appropriate potential window. [35] Among many organic materials used in organic electronics, polyaniline (PANI), a conjugated polymer, has been applied in OFETs [36][37][38] and OECTs [39][40][41] devices. Besides that, it is a first candidate for ambipolar OECT once it is stable in an aqueous environment and also presents reversible redox reaction in the electrochemical window causing electrochemical doping/dedoping, that is, injection of cations and anions from the electrolyte, enabling its ionic conduction.…”

“…Among many organic materials used in organic electronics, polyaniline (PANI), a conjugated polymer, has been applied in OFETs [ 36–38 ] and OECTs [ 39–41 ] devices. Besides that, it is a first candidate for ambipolar OECT once it is stable in an aqueous environment and also presents reversible redox reaction in the electrochemical window causing electrochemical doping/dedoping, that is, injection of cations and anions from the electrolyte, enabling its ionic conduction.…”