Chemical modification of nano-structured polyaniline by N-grafting of hexadecylbromide

Abstract

This study aims to explore an effective route for the preparation of conductive N-substituted polyaniline by incorporation of hexadecyl side chains into the fully reduced form of nano-structured polyaniline leucoemeraldine base. For this purpose, at first nano-structured emeraldine salt polyaniline was synthesized by interfacial chemical oxidative polymerization. The dark green product salt was neutralized by an ammonia solution in order to give us an emeraldine base (EB). Thereafter, the reduced form of nano-structured polyaniline was prepared by treating the obtained EB with phenylhydrazine in methanol. The excess amount of butyllithium was applied to abstract protons from the amine nitrogens of nano-structured LEB polyaniline chains. Thereafter, deprotonated polyaniline was reacted with hexadecylbromide to prepare poly(N-hexadecylaniline) through N-grafting reaction. The obtained poly(N-hexadecylaniline) was characterized using Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry, and thermal gravimetry analysis (TGA). The average diameters of unsubstituted and substituted polyaniline particles were determined by particle size analyzer. The optical properties of the poly(N-hexadecylaniline) in the undoped and doped state were obtained using UV–vis spectroscopy and the electrical conductivity of the sample was measured using sample in which the conductive materials were sandwiched between two Ni electrodes at room temperature. Also, electroactivity of the synthesized polymer was investigated under cyclic voltammetric conditions on the surface of the working glassy carbon electrode. The solubility of the obtained polymer was examined in common organic solvents.