Electrochemical synthesis of poly(2-methyl aniline): electrochemical and spectroscopic characterization

Abstract

Poly(2-methyl aniline) or poly(ortho-toluidine), as ring substituted derivative of aniline, has been synthesized electrochemically in various concentrations of H2SO4 and HCl, and then characterized by cyclic voltammetry, as well as by impedance and Raman spectroscopy. The cyclic voltammograms of poly(o-toluidine) and poly(aniline) show that the electrochemical polymerization of these two polymers proceeds by almost identical mechanisms. The Raman spectroscopical measurements suggest that the redox reactions of poly(aniline) and poly(o-toluidine) are similar in the potential range between -0.2 and 0.7V vs. SCE. The impedance measurements showed that the conductivity of poly(o-toluidine) is an order of magnitude lower than that of the corresponding poly(aniline) form.

A correlation of electrochemical and spectroelectrochemical properties of poly(o-toluidine)

“…However, the absence of this band at lower potentials in the present case and its appearance and gradual increase in intensity with the anodic sweep suggest this to be the feature of the quinoid-like rings in the oxidized form of the polymer [35]. A medium intensity band at 1269 cm −1 has been assigned to the C-N stretching vibrations of semiquinoid and quinoid rings [32].…”

“…A weak band appearing at 1122 cm −1 at E SCE = 0.20 V grows in intensity up to E SCE = 0.60 V and then decreases afterwards. This band corresponds to the C-C stretching vibration in the methyl substituted semiquinone and quinone rings [32]. Another band at 1177 cm −1 can be attributed to the C-H bending vibration mode of aromatic rings.…”

Electropolymerization kinetics of o‐aminophenol and characterization of the obtained polymer films

“…However, as soon as polymerization is nucleated, a brown polymer film is rapidly observed on the electrode surface. The potential difference between the first and the second oxidation peaks I and II is ≈1110 mV, and no middle peaks were observed between them, which confirm the nonexistence of degradation products, higher regularity, homogeneity, and adherence of the deposited film to the electrode surface 51. On reversing the potential scan from +1200 up to −400 mV, the reversing anodic current is very small, indicating the presence of adherent layer of the polymer on the electrode surface.…”

“…On the other hand, the second oxidation peak II, which is assigned to the oxidation of the adsorbed semiquinone radical cation (polaron state) to the quinone imine (bipolaron state),51 occurs at +810 mV vs. SCE, and is represented in Scheme . Therefore, the second anodic peak is attributed to the conversion of radical cations to the fully oxidized form (quinoidal structure).…”

Conducting polymer/bio‐material composite coatings for corrosion protection

“…The cyclic voltagrams (CV) obtained during electrochemical polymerization of 0.1 M aniline (A), 0.1 M o‐toluidine (OT), and 0.05 M aniline + 0.05 M o‐toluidine(A + OT) are shown in Figure a–c, respectively. Literature reports that acidic environment (low pH) favors the polymerization process of aniline/substituted aniline (o‐toluidine) . Aniline is much less easily oxidized at pH < 4 and results in the low yield of the polymer.…”