Synthesis and Properties of Conducting Polyaniline Doped with Compound Organic/Inorganic Acids

Polyaniline (PANI) were synthesized in compound organic/inorganic acids aqueous solution by chemical oxidization polymerization with aniline as monomer and ammonium persulfate as oxidant. The properties of the synthesized polyaniline were studied and characterized by four-probe, thermogravimetric analysis (DSC/TGA), FT-IR and Raman spectrometric analysis. The results show that, when the polymerization temperature is 20℃ and the mol concentration ratio of sulfosalicylic acid (SSA) to sulfuric acid (H2SO4) is 0.25:1, both the conductivity and the solubility (in NMP) of the synthesized doped polyaniline reach their maximum and they are 13.5 S?cm?1 and 85%, respectively. The DSC/TGA show that the synthesized polyaniline doped with compound organic/inorganic acids has better thermal stability than that of polyaniline doped with single acid. It was found that the good conductivity of doped polyaniline may be attributed to the dislocation of charge and the forming conjugation of molecular chain in the polyaniline after it is doped with protonic acid.