Electrochemical Oxidation of Polyaniline in Nonaqueous Electrolytes: "In Situ" Raman Spectroscopic Studies

Abstract

Spectroelectrochemical behavior of polyaniline in nonaqueous electrolytes has been studied by Raman spectroscopy using two excitation lines: blue (457 nm) and infrared (1064 nm). It has been demonstrated that in the electrolytic solution consisting of tetrabutylammonium tetrafluoroborate/diphenyl phosphate/acetonitrile both oxidation processes (oxidation of leucoemeraldine to emeraldine and emeraldine to pemigraniline) can be investigated by Raman spectroscopy. The blue excitation line is very insensitive to the oxidation and protónation changes occurring during the first oxidation process and reveals only the reduced segments of polyaniline chains. However in the second oxidation process significant changes in the Raman spectra occur, consistent with the formation of pemigraniline units accompanied by deprotonation of the polymer. No Raman spectrum can be recorded for the most reduced form of polyaniline using the infrared excitation line. However gradual oxidation of the polymer results in the appearance of the Raman bands characteristic of the oxidized units which are strongly resonantly enhanced. The infrared line is extremely sensitive toward the existence of protonated segments and allows for direct monitoring of the deprotonation processes occurring during the second oxidation process (i.e. the oxidation of emeraldine to pemigraniline).

Delineating Poly(Aniline) Redox Chemistry by Using Tailored Oligo(Aryleneamine)s: Towards Oligo(Aniline)‐Based Organic Semiconductors with Tunable Optoelectronic Properties

“…In order to compare this library of molecularly engineered, aniline-based organic semiconductors with the wellknown electrochemical behaviour of oligo-and poly-A C H T U N G T R E N N U N G (aniline)s, [38] cyclic voltammetry (CV) and differential pulsed voltammetry (DPV) investigations were carried out. [39] To provide insight into the results obtained, we will focus our discussion on the DPV measurements, as this provided a wealth of high quality data, which has not been seen to date for such electroactive species.…”

Electrochemistry of poly(3,4-ethylenedioxythiophene)-polyaniline/Prussian blue electrochromic devices containing an ionic liquid based gel electrolyte film

“…The broad cathodic wave shows no distinct redox peak, as the rate of pyrrolidinium ion elimination in the anodic process is greater than that of the cation intercalation reaction in the cathodic process. 28 Judging by the basis of the shape of the voltammograms in both anodic and cathodic branches, the film appears to be highly capacitive, and this is also ratified from the magnitude of charge inserted during oxidation which is 23 mC cm À2 , and the same quanta of charge is extracted in the reverse cycle (at 100 mV s À1 ), thus indicating good reversibility.…”

Palladium–Poly(3‐aminoquinoline) Hollow‐Sphere Composite: Application in Sonogashira Coupling Reactions

“…The band at 1463 cm À1 corresponds to the C=N stretching mode of the quinoid units. [29] A shoulderlike appearance at 1510 cm À1 results from the NÀH bending deformation band, whereas two other similar features at 1550 and 1572 cm…”

“…The peak at 1621 cm À1 is derived from the CÀC deformation vibration for the benzenoid ring, which is characteristic for semiquinone rings. [29,30] The peaks at 1590 and 1175 cm…”