Melt/solution processable conducting polyaniline: doping studies with a novel phosphoric acid ester

Polyaniline (PANI) was doped with a novel dopant, 3-pentadecylphenylphosphoric acid (PDPPA), having a long hydrophobic hydrocarbon side chain, either by mechanical mixing of emeraldine base and PDPPA or by the emulsion polymerization route using xylene or chloroform as the solvent. The resulting PANI–PDPPA complexes obtained were characterised by FTIR, UV–Vis, conductivity measurements, XRD, SEM, DSC, TGA and polarised light microscopy. The formation of the complex induces solubility of PANI in commonly used weakly polar or non-polar organic solvents such as xylene, THF, chloroform, etc. Protonation gives a plasticized PANI–PDPPA complex which can be processed by both thermal and solution techniques. On thermal processing, a free-standing flexible film with conductivities of the order 1.8 S cm−1 was obtained.