Polyaniline/polyvinyl alcohol blends: Effect of sulfonic acid dopants on microstructural, optical, thermal and electrical properties

This correspondence reports the preparation and performance of different polyaniline–polyvinyl blends (PANI–PVA) doped with sulfonated acids. PANI is prepared by in situ dispersion polymerisation, and a subsequent extensive study determines the effect of protonation upon doping with four different types of acids. We obtain the blends by changing the four different dopants, viz. β-naphtalenesulfonic acid (NSA), camphorsulfonic acid (CSA), dodecyl benzene sulfonic acid (DBSA) and p-toluene sulfonic acid (PTSA), while maintaining constant PANI and PVA concentrations. The polymer thin films are deposited on glass substrates by the dip-cast procedure. Lastly, the films of the obtained blends are characterised by surface, structural morphology (elemental analysis, AFM, SEM, FTIR and XRD), thermal properties (TGA and DSC) and UV–vis spectroscopy. The morphological analysis shows that the nanoparticles form different shapes, which depend on the type of dopant, whereas the FTIR spectra show the chemical interaction between the two polymers. The thermal study reveals three-step degradation of the polymer blends. To confirm the possible use of these blends in the electrical industry, the electrical properties are studied by in-plane I–V characteristics and four probe conductivity measurements.