Chemical and electrochemical synthesis of conducting graft copolymer of acrylonitrile with aniline

A new conducting copolymer, polyacrylonitrile-graft-polyaniline (PAN-g-PANi), has been prepared by chemical and electrochemical methods from a precursor polymer. Poly[acrylonitrile-co-(acrylimine phenylenediamine)] (PAN-co-PAIPD) was synthesized chemically by reacting PAN with sodium 1,4-phenylenediamine salt. PAN-g-PANi was synthesized chemically using ammonium peroxydisulfate as the oxidant and p-toluenesulfonic acid in dimethylsulfoxide solution and adding aniline to oxidized PAN-co-PAIPD. Electrochemical polymerization was carried out by spin coating PAN-co-PAIPD on the surface of a Pt electrode, then the growth of the graft copolymer (PAN-g-PANi) in the presence of fresh aniline and acidic solution. The structures of the graft copolymer and PAN-co-PAIPD were characterized using UV-visible, Fourier transform infrared, and H-1 and C-13 NMR spectroscopies. The thermal properties of PAN-g-PANi were studied using thermogravimetric analysis and differential scanning calorimetry. Scanning electron microscopy (SEM) images showed that the morphology of PAN-g-PANi copolymer films was homogeneous. Electrical conductivity of the copolymer was studied using the four-probe method, which gave a conductivity of 4.5x10(-3) S cm(-1) with 51.4% PANi. SEM and electrical conductivity measurements supported the formation of the graft copolymer. (C) 2006 Society of Chemical Industry.