Doped polyaniline/multi-walled carbon nanotube composites: Preparation, characterization and properties

This study reports the synthesis of doped polyaniline in its emeraldine salt form (PANI-ES) with carboxylic acid and acylchloride groups contained multi-walled carbon nanotubes (designated as c-MWNTs and a-MWNTs) by in situ polymerization. Both Raman spectra and HRTEM images indicate that carboxylic acid and acylchloride groups formed at both ends and on the sidewalls of the MWNTs. Based on the π–π* electron interaction between aniline monomers and functionalized MWNT and hydrogen bonding interaction between the amino groups of aniline monomers and the carboxylic acid/acylchloride groups of functionalized MWNT, aniline molecules were adsorbed and polymerized on the surface of MWNTs. Structural analysis by FESEM and HRTEM showed that PANI-ES/c-MWNT and PANI-ES/a-MWNT composites are core (c-MWNT or a-MWNT)- shell (doped-PANI-ES) tubular structures with diameters of several tens to hundreds of nanometers, depending on the PANI content. The conductivities of 0.5 wt% functionalized MWNT containing PANI-ES/c-MWNT and PANI-ES/a-MWNT composites are 60–70% higher than that of PANI without MWNT.