In-situ deposition of polyaniline and polypyrrole electroconductive layers on textile surfaces by the reactive ink-jet printing technique

Abstract

A facile and original method of deposition of polyaniline (PANI) and polypyrrole (PPy) by reactive ink-jet printing on different textile fabrics is proposed. Polyaniline- and polypyrrole-coated conducting fabrics were obtained by chemical oxidation of aniline hydrochloride or pyrrole by ammonium peroxydisulfate on polyacrylonitrile (PAN), cotton, poly(ethylene terephthalate) (PET), cotton/PET, wool, and cotton/wool fabrics. The conducting fabrics were characterized chemically by means of Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and energy-dispersive spectroscopy (EDS). The morphology of the coatings was observed by optical microscopy and scanning electron microscopy (SEM). The conducting properties (surface resistance) of the fabrics were measured by means of the four-probe method. The optimal conditions of the PANI and PPy deposition on textiles by reactive ink-jet printing were established. The obtained results prove that the proposed method is very simple, practically could be carried out on the basis of water-containing inks, giving a very good adhesion of the in-situ formed conductive polymer to the substrate and ensuring a very low surface resistance. The variation of the surface resistance vs. concentration of aniline hydrochloride or pyrrole for different textile fabrics was obtained. The mechanism of the PANI and PPy deposition and adhesion on textiles based on the electrokinetic phenomena is proposed and proved by the changes in relative resistance of PANI/PAN and PPy/PAN composites during the multi-cyclic flexing, washing and dry-cleaning processes, and re-doping with HCl. An application of PANI and PPy conductive textiles in electromagnetic interference (EMI) shielding is proposed. The results showed that PANI/PAN and PPy/PAN composites achieved very good and moderate EMI shielding effectiveness, respectively.