Synthesis and Characterization of Conducting Polymer Polyaniline

Abstract

The polyaniline (insulating and conducting) has been synthesized by chemical polymerization technique. The synthesized samples of polyaniline have been characterized by using Fourier Transform Infrared, Ultraviolet-visible spectroscopy, Thermogravimetric analysis and Cyclic voltammetry techniques. The vibration band at 1169.25 cm-1 observed in undoped polyaniline is due to presence C-N double bond and indicative of protonation. After doping this vibration band has been shifted to 1129.28 cm-1. Two electronic transitions at 325.24 nm (3.9 eV) and 638 nm (2 eV) have been found in Ultraviolet-Visible spectrum, which correspond to diphenyl paraphenylene diamine and diphenyl paraphenylene diimine structure respectively. Large weight loss in Thermogravimetric analysis and results at 400˚C suggests that polymer degrades after 400˚C. The cyclic voltammetric of polyaniline exhibit two redox peaks at 0.18 and 0.75 volts which are characteristics to the polyaniline. Moreover, the increase in intensity of voltammetric current with the increasing number of scanning cycles might be attributed polymer forming on the electrode surface.