Electrochemical polymerization and spectroscopic investigation of 2-methylindole

Synthesis of poly (2-methylindole) (P2MI) was achieved by direct anodic oxidation of 2-methylindole in LiClO4/acetonitrile solution. The P2MI film was generated potentiodynamically between 0.00 V and +1.80 V (vs. Ag/AgCl, saturated KCl). The oxidation of 2-methylindole in this medium was initiated at +0.65 V. The electroactive P2MI film exhibited a good air stability and electrochromic properties. The P2MI film presented an electrical conductivity close to 10−3-10−4 S cm−1. Electrochemical polymerization mechanism of 2-methylindole was proposed as 3-6 linkage sites of the monomer. P2MI film was characterized by cyclic voltammetry, dry conductivity measurements, scanning electron microscopy (SEM) pictures, electron spin resonance (ESR), Fourier transfer infrared (FT-IR) and electrochemical impedance spectroscopies (EIS).