Characterization and electrochemical properties of poly(aniline-co-o-methoxyaniline)/multi-walled carbon nanotubes composites synthesized by solid-state method

The composites of copolymers of aniline (An) and o -methoxyaniline (OMA) with multi-walled carbon nanotubes, named as copolymers/MWNT, (poly(An-co-OMA)/MWNT) were prepared by solid-state synthesis method at room temperature. The homopolymers/MWNT composites were synthesized for comparison. The structure and morphology of these composites were characterized by FT-IR spectroscopy, UV-Vis absorption spectroscopy, X-ray diffraction (XRD) and TEM. The electrochemical performances of the composites were investigated by galvanostatic charge-discharge, cyclic voltammetry (CV) and cycle life measurements. The results from FT-IR and UV-Vis spectra showed that different molar ratio of [An]/[OMA] in reaction system has great influence on the oxidation degree, conjugation length and doping level of the copolymers in these composites. The presence of MWNT in the composites was confirmed from the characteristic peaks of MWNT in XRD patterns and the enwrapped MWNT in TEM images. The TEM images further indicates that the MWNT uniformly distributed and enwrapped with polymer in the case of composite from molar ratio of [An]/[OMA]=1:1. The results also showed that the morphology, crystallinity and solubility of composites were highly affected by the incorporation of OMA unit copolymer chain. The results from electrochemical performances suggested that the molar ratio of [An]/[OMA]=3:1 in reaction system can make the obtained composites displayed a higher specific capacitance, good rate ability and cycling stability.