Aqueous Dispersions of DBSA-Doped Polyaniline: One-Pot Preparation, Characterization, and Properties Study

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+center dot center dot center dot SO3- 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. (C) 2009 Wiley. Periodicals, Inc. J Appl Polym Sci 113: 3980-3984, 2009