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Keywords:

  • aqueous dispersions;
  • thermal stability;
  • polyaniline;
  • dodecylbenzene sulfonic acid;
  • polymerization

Abstract

Aniline was polymerized in the presence of dodecylbenzene sulfonic acid (DBSA) as a functionalized protonic acid, in an aqueous medium to directly synthesize polyaniline (PANI)-DBSA particles. DBSA acted as a dopant and a surfactant with stabilizing PANI-DBSA dispersions by formation of strong hydrogen bonds. The NH+…SOmath image interactions between the PANI chains and the DBSA appeared at 1026 cm−1 in Fourier transform infrared (FTIR) spectrum. Elemental analysis was used to determine the degree of sulfonation (S/N ratio) of PANI chains and resulted that the sulfur-to-nitrogen ratio is 0.35. Thermogravimetric analysis (TGA) technique was used to analyze thermal properties of the particles and resulted that the synthesized PANI-DBSA particles have high thermal stability. The moisture, DBSA and PANI contents of the PANI-DBSA were estimated from TGA curve, and then the number of aniline repeating units doped with one DBSA molecule was approximately calculated. X-ray diffraction (XRD) analysis confirmed that a chemical crosslinking reaction occurs between the PANI chains during thermal treatment of PANI-DBSA. The morphology of PANI-DBSA powder was investigated by scanning electron microscopy technique and showed that the PANI particles develops from round particles to a smooth surface. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009