Self-assembled films based on polyaniline/multiwalled carbon nanotubes composites and sulphonated polystyrene deposited onto ITO substrates

• Production of a new self-assembled (SA) film based on a polyaniline (PAni) and functionalized multiwalled carbon nanotubes (MWCNT) composites with alternated layers of sulphonated polystyrene (PSS)
• Two additional films based on alternated layers of PAni, MWCNT and PSS were produced, characterized and compared to PAni-MWCNT/PSS film.
• Synergic effects of the PAni-MWCNT/PSS film were observed without any changes of final morphology.

In this work, a self-assembled (SA) film based on a composite of polyaniline (PAni) and functionalized carbon nanotubes (MWCNT) with alternated layers of sulphonated polystyrene (PSS) was produced and characterized. Two other SA films (PAni/PSS/MWCNT/PSS and PAni/PSS) were produced to compare the results. The composite PAni-MWCNT was characterized by scanning electron microscopy (SEM) and Fourier transformed infrared (FTIR) analysis. The results showed that the synthesis procedure was effective in covering the MWCNTs surface by PAni particles. The SA films were characterized by scanning electron microscopy (SEM), UV–vis spectrophotometry (UV–vis) and cyclic voltammetry (CV) techniques. SEM images showed that morphologies of PANi/PSS and PAni-MWCNT/PSS were similar. The UV–vis and CV results indicated increase of absorbance values as well as the current signals for each bilayer deposited. However, SA film with PAni composite (PAni-MWCNT/PSS) presented a significant increase in its current peaks. The authors suggested that the increase in the current peaks was attributed to a synergic effect of the PAni-MWCNT composite with the subsequent decrease of the charge transfer resistance and, consequently, increase of the film conductivity. These results can be used by promoting these films as possible sensors or biosensors.