Polypyrrole coated carbon nanotubes: Synthesis, characterization, and enhanced electrical properties

We describe a simple approach to the synthesis of MWNT/polypyrrole nanotubes by the in situ chemical polymerization of pyrrole on the carbon nanotubes using ferric chloride as an oxidant. The effects of pyrrole concentration on the coating and properties of the resulting complex nanotubes were studied by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction, and thermal gravimetric analysis. The coated PPy layers could be controlled easily by adjusting a feed ratio of pyrrole to MWNTs. FT-IR results suggested an existence of interaction between the –COOH groups of chemically modified MWNTs and NH groups of the PPy. SEM and TEM studies indicated that each individual MWNT could be coated with PPy. The resultant nanotubes enhanced electrical conductivity compared to PPy and MWNT which was strongly influenced by the feed ratio of pyrrole to MWNTs.