Role of Protonic and Charge Transfer Doping in Solid-State Polyaniline

Abstract

Addition of triflate salts to the emeraldine base form of polyaniline in the solid state causes a lowering of its work function but not an increase of its conductivity. It is postulated that this effect is due to the formation of localized energy states in the band gap. On the other hand, strong protonic acids such as triflic acid as well as tetrafluoroboric acid lower both the work function and increase the conductivity of PANI-EB according to the known protonic form of the doping mechanism. The difference between these two kinds of doping has been demonstrated by measurement of the work function, conductivity, UV−vis, and IR spectroscopy.

Polymerization of aniline under various concentrations of APS and HCl

“…For case (C), the main features of doped and dedoped samples are associated with ES PANI (with green color for the test solution) and EB PANI (with blue color), respectively. 15,[21][22][23][32][33][34][35] The two bands at 382 and 473 nm observed in the ES PANI samples are attributed to the p-p* transition and to the polaron-p* transition, respectively. 15,[21][22][23]34 The two bands at 325 and 631 nm observed in the EB PANI samples are related to the p-p* transition in benzenoid rings and to the charge-transfer-exciton transition formed in a benzenoid ring with its adjacent quinonoid ring, respectively.…”

“…15,[21][22][23]34 The two bands at 325 and 631 nm observed in the EB PANI samples are related to the p-p* transition in benzenoid rings and to the charge-transfer-exciton transition formed in a benzenoid ring with its adjacent quinonoid ring, respectively. 35 …”

Reduction of and in polyaniline: Catalytic oxidation of methanol at morphologically different composites

“…The charge for the proton expulsion for each electrode was calculated and all electrodes used in this study were within 2% of the same value to ensure comparable numbers of electroactive sites in the polymer membrane. The cyclic voltammetric responses of PANI membrane electrodes in solutions containing 2.0 · 10 À2 M PtCl 2À 4 and PtCl 2À 6 in 1 M HClO 4 are provided in Fig. 1b and c. The PANI/Pt composite electrodes were produced using the same potential window and 10 complete reduction cycles for each electrode were performed.…”

“…The materials are versatile and have been used for applications including coatings, sensing and catalysis. Polyaniline (PANI) is unique among this class of polymers due to the fact that acid doping (pH) [1][2][3][4] and the oxidation state [5,6] of the material strongly influence its conductivity. Optimum conductivity is maintained when the polymer contains equal numbers of oxidized and reduced units with proton doping [7,8].…”

Anthraquinonedisulfonate Doped Polyaniline as an Acceptor‐Donor System for Electrocatalysis of Oxygen Reduction

“…The analysis of the spatial distribution of frontier orbitals with the highest occupied molecular orbital-lowest unoccupied orbital (HOMO-LUMO) [27,31,32] gives an inside view of PANI/AQDS modified electrode when it is used as the electrocatalyst for ORR. The charge transfer should involve the injection of electrons from electrode into PANI with LUMO turning to HOMO, the electron-transfer inside the PANI/AQDS complex, and the injection of electrons from AQDS to dissolved O 2 .…”