Conductive composites of polyaniline–polyacid complex and graphene nanostacks

[Display omitted] •Nanocomposites of graphene and polyaniline–polyacid complexes are elaborated.•Graphene oxidation degree influences electronic properties of the nanocomposites.•Role of various interactions in graphene–polyaniline–polyacid system is revealed.•Origin of the distribution and size of graphene stacks in nanocomposite is shown.•Electrical conductivity of nanocomposite is tuned within three orders of magnitude. Nanocomposites based on graphene and polyaniline–polyacid complexes with tunable electrical conductivity are elaborated. An influence of graphene oxidation degree on conductivity of the nanocomposites is investigated. The change of optical and electrical properties after graphene introduction into polyaniline–polyacid complexes is explained by the formation of graphene nanostacks of different size and their different distribution in the film bulk. The role of (i) internal interactions between graphene sheets revealed by high-resolution TEM and AFM and (ii) external interactions between graphene and polyaniline or polyacid of different hydrophobicity elucidated by UV–vis, FTIR-spectroscopies and pH-measurements is discussed. In case of uniform distributed graphene sheets having a low oxidation degree, the electrical conductivity of the nanocomposites based on polyaniline complexed with more hydrophilic polyacid increases up to 20 times in respect to initial polyaniline complex.