Stability of polyaniline synthesized by a doping–dedoping–redoping method

Stability, including thermal stability, conductivity stability in air and after thermal treatment (100–200°C), of the polyaniline (PANI) films synthesized by a doping–dedoping–redoping method was investigated. It was found that thermogravimetric analysis (TGA) curves undergo three steps: loss of water or solvent, dedoping and decomposition, and those depend on the counterions. Compared with PANI films doped with camphor sulfonic acid (CSA) in m-cresol, the thermal stability of the doped PANI films is improved by the new method, and thermal stability in the order of PANI–H3PO4 > PANI–p-TSA > PANI–H2SO4 > PANI–HCl, PANI–HClO4 > PANI–CSA was observed. The conductivity of the doped PANI films at room temperature was reduced after thermal treatment, and it is dependent of the counterions. It was found that the conductivity stability of PANI–p-TSA and PANI–CSA is the best below 200°C. When the doped PANI films were placed in air, their conductivity decrease slowly with time due to deproton, and also depends on the counterions. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 615–621, 1999

[1]  Tsuneo Hagiwara,et al.  Thermal stability of polyaniline , 1988 .

[2]  H. Ishikawa,et al.  Thermal stability of chemically synthesized polyaniline , 1994 .

[3]  Wu-Song Huang,et al.  Polyaniline, a novel conducting polymer. Morphology and chemistry of its oxidation and reduction in aqueous electrolytes , 1986 .

[4]  K. Neoh,et al.  Polyaniline treated with organic acids: doping characteristics and stability , 1995 .

[5]  A. Heeger,et al.  Counter-ion induced processibility of conducting polyaniline and of conducting polyblends of polyaniline in bulk polymers , 1992 .

[6]  S. Palaniappan,et al.  Temperature effect on conducting polyaniline salts: Thermal and spectral studies , 1994 .

[7]  X. Jing,et al.  Thermal behaviors of doped polyaniline , 1995 .

[8]  Arthur J. Epstein,et al.  Secondary doping in polyaniline , 1995 .

[9]  Alan G. MacDiarmid,et al.  ‘Polyaniline’: Protonic acid doping of the emeraldine form to the metallic regime , 1986 .

[10]  A. MacDiarmid,et al.  Polyaniline: Protonic Acid Doping to the Metallic Regime , 1985 .

[11]  Anjan Ray,et al.  Polyaniline: Processability from aqueous solutions and effect of water vapor on conductivity , 1987 .

[12]  J. Travers,et al.  Water effects in polyaniline: NMR and transport properties , 1987 .

[13]  Alan J. Heeger,et al.  Thermal stability of polyaniline networks in conducting polymer blends , 1996 .

[14]  X. Jing,et al.  Thermal behavior of intrinsic polyaniline and its derivatrives , 1994 .

[15]  M. Wan,et al.  Porous polyaniline films with high conductivity , 1998 .

[16]  C. Riekel,et al.  The effect of heating on polyaniline powders studied by real‐time synchrotron radiation diffraction, mass spectrometry and thermal analysis , 1992 .