Chemical in situ polymerization of polypyrrole on bacterial cellulose nanofibers

Conducting porous nanofibrous composite membranes of bacterial cellulose (BC) and polypyrrole (PPy) were prepared through in situ oxidative chemical polymerization of pyrrole (Py) on the surface of synthetized BC nanofibers by using FeCl3 as oxidant agent. The influence of polymerization conditions on electrical conductivity, morphological and thermal stability of the BC/PPy composites was investigated. The amount of PPy deposited on the BC nanofibers increased with increasing the monomer concentration and reaction time while the electrical resistivity of the composites decreased due to the formation of a continuous layer that coated the nanofiber surface. Fourier transform infrared (attenuated total reflectance mode) spectroscopy (FTIR-ATR) of the composites revealed strong interaction between PPy and BC, as characterized by a blue-shift of C-N band of PPy towards pure PPy with increasing Py concentration. BC/PPy composites showed higher thermal stability than BC membrane due to the protective effect of the conducting polymer coating. Scanning electron microscopy (SEM) analysis of the composites revealed that PPy consisted of particles of mean size of 35 nm that form a continuous coating that fully encapsulates the BC nanofibers. The material properties obtained by the method described in this work for the BC/PPy composites open interesting possibilities for novel applications of electrically conducting bio-based composites, particularly those that may exploit the biocompatible nature of the BC/PPy membranous composite.