Electrical properties and EMI shielding behavior of highly thermally stable polyaniline/colloidal graphite composites

A hybrid approach has been adopted by using a combination of colloidal graphite (CG) as a conducting filler, S-lithium sulfoisophthalic (LiSIPA) acid as a dopant, and polyaniline (PANI) as a matrix to prepare LiSIPA doped PANI-CG composites. The thermal stability (similar to 300 degrees C) and electrical conductivity (67.4S/cm at 17.4% CG content) have been improved significantly as compared to PANI doped with conventional inorganic dopants like HCI or H2SO4 (130-150 degrees Q. The maximum shielding effectiveness value was found to be -39.7 dB. X-ray diffraction and infrared spectroscopy showed a systematic shifting of the characteristic peaks and bands with increase in the amount of CG, which indicates significant interaction exists between CG and PANI. The UV-Vis spectra showed the characteristic bands of PANI, with a shift to shorter wavelength with increase in the CG content. The interaction mechanism between doped PANI and CG in the resultant composites has been proposed. Copyright (C) 2009 John Wiley & Sons, Ltd. Supporting information may be found in the online version of this paper.