In Situ UV-Visible Spectroelectrochemistry and Cyclic Voltammetry of Conducting N-Methylpyrrole: Indole Copolymers on Gold Electrode

Abstract

Electrochemical copolymerization of N-methylpyrrole (NMPy) and indole (In) in various monomer ratios were carried out by potentiodynamically methods in acetonitrile electrolyte containing LiClO 4 on gold electrode. The obtained homopolymers and copolymers were characterized with cyclic voltammetry (CV), in situ UV-Visible, FT-IR spectroscopy, scanning electron microscopy (SEM) and in situ resistivity measurements. The cyclic voltammetry study shows that the onset potential for the monomers and co monomers curves is located at the different values for N-methylpyrrole, indole and N-methylpyrrole-indole. There is a nucleation process followed by growth of nuclei to continuous films. The oxidation and reduction peaks for copolymer, P(NMPy-In), which synthesized from the 1:1 mole-mole ratio concentration of the relevant monomers, located between those for poly Nmethylpyrrole (PNMPy) and polyindole (PIn) films. The observed values were showed a decreased [NMPy]/[In] ratio concentration in the copolymers shifts the peak potential to more positive. The in situ UV-Visible, FT-IR spectroscopy and SEM analysis of homopolymers and copolymers were also studied. The result shows the intermediate spectroscopic properties between homopolymers and copolymers. The in situ resistivity measurements showed that the copolymers have a lower conductivity than the corresponding parent homopolymers.

Kinetic and In Situ Spectroelectrochemical Studies of Conducting Polypyrrole and Its Substituted Growth on Gold and ITO Glass Electrodes

“…Detail of SEM image of PIn was reported previously. 28 PIn shows a "dry mud cracks texture" with smooth surface shape. The pictures taken for P(Py-In) becomes more cross-linked as it grows with small circular particles aggregated.…”

Enhanced electrical conductivity of polyindole prepared by electrochemical polymerization of indole in ionic liquids

“…Initial CVs of indole monomer in a LiClO 4 /ACN and ionic liquid solvents ([BMIm] [BF 4 − ], [BMIm] [PF 6 − ] and [EMIm] [NTf 2 − ]) shows a steep current increase around 0.66, 0.76, 0.91, and 0.83 V in the positive going scans and in the negative going scans trace crossing occurs at 0.58, 0.71, 0.91, and 0.83 V, respectively. PIn films grows on the electrode surface during the electropolymerization process and oxidation peaks are observed around 0.60, 0.87, and 0.90 V in LiClO 4 /CAN, [BMIm] [BF 4 − ] and [BMIm] [PF 6 − ] during further oxidative polymerization, respectively.…”

“…Reaction equipment and chemicals are described in an earlier paper . Films of PIn were prepared from 0.1 M solutions of indole in two ionic liquids, a solution of 0.1 M [BMIm] [BF 4 − ] and [BMIm] [PF 6 − ] (Merck) or a solution of 0.1 M LiClO 4 /ACN.…”

“…PIn is traditionally performed in an electrolyte‐molecular solvent system . The size and nature of the dopant counter‐ions from the electrolyte‐molecular solvent system, and the nature of the solvent itself, can have a marked influence on the properties of the resultant polymer film . PIn films was mainly performed in ACN and CH 2 Cl 2, using ClO 4 − or BF 4 − as the supporting electrolyte.…”

“…It means that, they are recyclable and more environmentally benign than most conventional organic solvents. Recently, we found that high‐quality polymer films of PIn with good electrical properties can be electro‐synthesized in LiClO 4 − /ACN on gold electrode . In this communication, we use of three ionic liquid such as [BMIm] [BF 4 − ], [BMIm] [PF 6 − ], and [EMIm] [NTf 2 − ] for the electrochemical polymerization of indole and compare this to the use of conventional solvent‐electrolyte systems (LiClO 4 /ACN).…”