Charge transport in benzoic acid-doped polyaniline films

In this work, undoped and doped polyaniline (PANI) films with benzoic acid were fabricated using N-methyl-2-pyrrolidone (NMP) as the solvent. Doped PANI films were prepared from 0 to 25 wt% contents of benzoic acid. Spectroscopic and electrical measurements were made to elucidate the doping effect caused by benzoic acid. Films doped up to 15 wt% showed an increased electrical conductivity attributed to the combined effects of protonation and counter ion interaction with the polymer chains. Films with superior benzoic acid contents (e.g., 20 and 25 wt% of benzoic acid) showed a continued increase in the conductivity. The results also revealed that there is an excess of counter ions in these films responsible for making the inter-chains conductivity more difficult. The evolution of the conductivity with the doping degree was discussed using an equivalent circuit model. [Display omitted] •Facile preparation of conductive benzoic acid doped PANI films is reported.•Benzoic acid doped PANI films present a well-defined electrical response to the electronic intra-chain conduction.•The counter ions adsorption on polarons sites contributes to increasing the film conductivity.•The excess of ‘free’ benzoate counter ions between PANI chains makes the inter-chain charge transport more difficult.