Synthesis and characterization of soluble conducting poly(aniline-co-2, 5-dimethoxyaniline)

Abstract

Copolymers of 2,5-dimethoxyaniline (DMA) with aniline (ANI), poly(DMA-co-ANI), were prepared for different molar feed compositions of DMA/ANI ( f DMA/ f ANI) by chemical oxidative polymerization using ammonium persulfate as oxidant. The copolymers were characterized by elemental analysis (EA), cyclic voltammetry (CV), Fourier transfer infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). EA results show that molar composition of DMA units ( F DMA) increased with increasing f DMA up to 0.60. A compositional drift in F DMA was noticed when the feed ratio of DMA was increased beyond 0.60. The redox characteristics of the copolymers with different F DMA were found to show variations than PDMA and PANI. UV–Visible spectroelectrochemical studies, TGA and FTIR spectroscopic analysis were used to identify the differences in the optical, thermal properties and structure between the copolymers and PDMA or PANI. The conductivity of the copolymer was found to decrease with increasing F DMA. The copolymers were soluble in N-methylpyrroldione, dimethylformamide, tetrehydrofuran and acetone. The solubility of the copolymers increased with increasing F DMA. The presence of –OCH 3 groups in the phenyl ring of DMA units induced easy oxidation and better solubility for the copolymers in comparison with PANI.