Synthesis and electrical properties of carbon nanotube polyaniline composites

A multiwalled carbon nanotube/polyaniline composite with cablelike morphology has been synthesized by an in situ chemical oxidative polymerization directed with cationic surfactant cetyltrimethylammonium bromide. It is interestingly found that with increasing carbon nanotube loading from 0 to 24.8 wt%, the conductivity increases by two orders of magnitude and the Mott's characteristic temperature T-0 which depends on the hopping barrier decreases by three orders of magnitude. Furthermore, the low-temperature magnetoresistance has also changed the sign from positive to negative. The results reveal a strong coupling between the carbon nanotube and the tightly coated polymer chains, which enhances the average localization length and the electronic properties of the composites. (C) 2004 American Institute of Physics.