In this study, we investigated the preparation and characterization of flexible conductive fiber membranes (BC/PPy) using different metal salt oxidants on bacterial cellulose (BC) and pyrrole (Py) in the in situ polymerization and co-blended methods, respectively. The effects of these oxidants, namely, ferric chloride hexahydrate (FeCl3·6H2O) and silver nitrate (AgNO3), on the structural characterization, conductivity, resistance value and thermal stability of the resulting materials were assessed by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). A comparative study revealed that the BC/PPy conductive fiber membrane prepared using FeCl3·6H2O as the oxidant had a resistance value of 12 Ω, while the BC/PPy conductive fiber membrane prepared using AgNO3 as the oxidant had an electrical resistance value of 130 Ω. The conductivity of the same molar ratio of BC/PPy prepared using FeCl3·6H2O as an oxidant was 10 times higher than that of the BC/PPy prepared using AgNO3 as an oxidant. Meanwhile, the resistance values of the conductive fiber membranes prepared from BC and PPy by the co-blended method were much higher than the BC/PPy prepared by in situ polymerization. SEM and XPS analyses revealed that when FeCl3·6H2O was used as the oxidant, the Fe-doped polypyrrole conductive particles could form uniform and dense conductive layers on the BC nanofiber surfaces. These two metal salt oxidants demonstrated differences in the binding sites between PPy and BC.
Keywords: bacterial cellulose; conductive membrane; in situ polymerization; metal salt oxidants; polypyrrole.