Electrochemical functionalization of single walled carbon nanotubes with polyaniline in ionic liquids

Single walled carbon nanotubes (SWNTs) are covalently functionalized during the electropolymerization of aniline in ionic liquids. In our experiment, 1-butyl-3-methyl-imidazolium hexafluorophosphate (BMIPF6) containing 1 M trifluoroacetic acid (CF3COOH) was selected as the ionic liquid media to separate SWNTs and to perform the electropolymerization of aniline within. The morphology of the resulting composite material of SWNT and polyaniline (PANI) was studied by scanning electron microscopy (SEM). Covalent bonding was evidenced by the increase of intensity ratio of the D band vs. G band in the Raman spectrum, whilst SWNTs may also be incorporated as big dopant anions to the PANI backbone. This paper provides a novel method by which large amount of SWNTs (15 mg/ml) can be modified by aniline electrochemically. p-type conducting polymer and n-type SWNTs can be thus copolymerized and applied to organic photovoltaics.