Vapour-phase polymerization of pyrrole on cellulose-based substrates

Conducting textiles were prepared embedding polypyrrole in natural and man made cellulose-based fibres, such as cotton, viscose, cupro and lyocell, by means of in situ polymerisation. Chemical vapour phase deposition of polypyrrole is a suitable process to produce electro-conductive composites in two steps: a) fabric impregnation with an aqueous solution of oxidant and dopant and subsequent drying; b) exposition to pyrrole vapour and polymerisation. Comparative morphological and structural analysis was carried out on the conducting viscose prepared with both vapour-phase and liquid-phase processes and some significant differences in the structural, calorimetric and electrical properties were pointed out, due to the different methods of preparation. The fabrics show a high uniform polypyrrole coating on the fibre surface, with its partial penetration inside the amorphous zones of fibre bulk. WAXD analysis shows that the conducting fabrics preserve the crystalline structure of the cellulose matrix, while SAXS results evidence the presence of a nanoparticle dispersion of polypyrrole in the cellulose matrix. polypyrrole-cellulose conducting composites have a particularly wash and light-fast consistence as shown by the tests performed.