Synthesis and characterization of carbon nanotube/polypyrrole core-shell nancocomposites via in situ inverse microernulsion

We demonstrate here a feasible approach to the preparation of multi-walled carbon nanotube (MWNT)/polypyrrole (PPy) core-shell nanowires by in situ inverse microemulsion. Transmission electron microscopy and scanning electron microscopy showed that the carbon nanotubes were uniformly coated with a PPy layer with a thickness of several to several tens of nanometers, depending on the MWNT content. Fourier transform infrared spectra suggested that there was strong interaction between the pi-bonded surface of the carbon nanotubes and the conjugated structure of the PPy shell layer. The thermal stability and electrical conductivity of the MWNT/PPy composites were examined with thermogravimetric analysis and a conventional four-probe method. In comparison with pure PPy, the decomposition temperature of the MWNT/PPy (1 wt % MWNT) composites increased from 305 to 335 degrees C, and the electrical conductivity of the MWNT/PPy (1 wt % MWNT) composites increased by 1 order of magnitude. The current-voltage curves of the MWNT/PPy nanocomposites followed Ohm's law, reflecting the metallic character of the MWNT/ PPy nanocomposites. The cyclic voltammetry measurements revealed that PPy/ MWNT composites showed an enhancement in the specific charge capacity with respect to that of pure PPy. (c) 2005 Wiley Periodicals, Inc.