Redox behavior of crosslinked polyaniline films

Abstract

Os processos redox da polianilina dopada secundariamente e dopada primariamente pré-aquecidas (150 o C, 6-12 horas) foram investigados pela espectroscopia Raman ressonante in-situ. Os espectros Raman do polímero dopado secundariamente mostram uma maior dependência com o aumento do potencial do que o polímero dopado primariamente pré-aquecido. Estes diferentes comportamentos foram atribuídos à presença de diferentes graus de ligações cruzadas nos polímeros. A presença de diferentes quantidades de ligações cruzadas foi confirmada por análise termogravimétrica, espectroscopia UV-vis e voltametria cíclica.The redox processes of secondarily doped and the pre-heated primarily doped polyaniline (150 o C, 6-12 h) were investigated by in-situ resonance Raman spectroscopy. Raman spectra of secondarily doped polymer is more dependent on potential than those observed in the pre-heated primarily doped polymer. These different behaviors were attributed to the presence of different degree of crosslinking in the polymers. The presence of different amounts of crosslinking was confirmed by thermogravimetric analysis, UV-vis spectroscopy and cyclic voltammetry.

Improving cyclic stability of polyaniline by thermal crosslinking as electrode material for supercapacitors

“…8 that the CPANI electrodes exhibited the improved electrochemical stability due to a higher conjugated degree than the untreated PANI, which reduced the anion exchange, and hindered the swelling and shrinking of the molecular chains by the electrolyte. 32 The PANI-160 electrode showed the maximum capacitance retention of 88.81%. With further increase of the heat-treating temperature and time, the capacitance retention of the CPANI electrodes decreased because of the oxidation reaction of polyaniline occurred during the heat-treating.…”

Sulfonated polyaniline: influence of sulfonation routes on its thermal and structural characteristics

“…Two strong, sharp and intense peaks around 615 and 576 cm -1 came out in the sulfonated polyanilines. Using Raman resonance spectroscopy, Temperini et al 20 detected these bands in redox process of polyaniline secondarily doped with camphorsulfonic but their attribution was not estabilished sharply. Herein, these bands could be ascribed to the formation of the emeraldine salt along the backbone of the PAni chains and could be associated to additional vibrational modes of the nitrogen-hydrogen and oxygen-hydrogen bonds of the sulfonic and amine groups.…”

Optimizing Lignosulfonic Acid-Grafted Polyaniline as a Hole-Transport Layer for Inverted CH3NH3PbI3Perovskite Solar Cells

“…A small shift of the primary quinoid rings' C−H occurred at 1168 cm −1 in treated LS-PANI-CSA, compared to 1178 cm −1 in untreated LS-PANI-CSA; this shift is attributed to the same mode in the benzoid segments. 53 Furthermore, the band at 1465 cm −1 , assigned to the CC stretching vibration of the quinoid ring, was strong in the DMSO-treated film spectra but not as evident in the untreated film, which likely still had m-cresol on the surface. These changes can be attributed to the polymer having a more quinoid-like character 51,54 and, as was stated in the section on UV−vis, the removal of the dopant (e.g., CSA) and residual m-cresol solvent by treatment.…”

“…Results indicated that the treated LS-PANI-CSA film (Figure e) peaks shifted, and peak intensities were reduced for the C–N + quinoid ring (∼1337 cm –1 ) and delocalized polaron vibrations (∼1383 and ∼1642 cm –1 ) in the extended polymeric conformation. A small shift of the primary quinoid rings’ C–H occurred at 1168 cm –1 in treated LS-PANI-CSA, compared to 1178 cm –1 in untreated LS-PANI-CSA; this shift is attributed to the same mode in the benzoid segments . Furthermore, the band at 1465 cm –1 , assigned to the CC stretching vibration of the quinoid ring, was strong in the DMSO-treated film spectra but not as evident in the untreated film, which likely still had m -cresol on the surface.…”