Eur. Phys. J. Appl. Phys.
Volume 46, Number 2, May 2009
|Number of page(s)||10|
|Section||Physics of Organic Materials and Devices|
|Published online||03 April 2009|
Dielectric and rheological properties of polyaniline organic dispersions
Laboratoire de Nanomatériaux et des Systèmes pour l'Énergie,
Centre de Recherches et de Technologies de l'Énergie, Technopole de Borj
Cedria, BP 95, 2050 Hammam Lif, Tunisia
2 Laboratoire de l'Intégration du Matériau au Système, UMR CNRS 5218, ENSCPB, 16 av. Pey Berland, 33607 Pessac, France
Corresponding author: firstname.lastname@example.org
Revised: 23 December 2008
Accepted: 12 February 2009
Published online: 3 April 2009
This paper reports the examination of the evolution of polyaniline-organic solvent interactions in the temperature range of 294–353 K. For this purpose, rheological and dielectric investigations have been undertaken for dispersions of plast-doped polyaniline in two different solvents (dichloroacetic acid and formic acid/dichloroacetic acid mixture). Dielectric permittivity has been investigated using the open ended coaxial line method in the frequency range of [100 MHz, 10 GHz]. Dielectric loss spectra of both dispersions showed a relaxation peak which was well fitted by Havriliak-Negami function. The relaxation was attributed to a Maxwell Wagner Sillars relaxation within polyaniline clusters. The difference found between relaxation parameters of the pure solvent and polyaniline dispersions was attributed to the solvent/polyaniline interactions. The relaxation time relative to the PANI/DCAA dispersion followed an Arrhenius law. While a Vogel-Fulcher-Tammann law was found for the relaxation time of PANI/DCAA-FA dispersion. Above a certain temperature, 318 K for PANI/DCAA and 313 K for PANI/DCAA-FA, the rheological parameters of the dispersions changed, thus indicating a morphological change of polyaniline in the dispersion. In the same range of temperature, α and β relaxation parameters undergo significant changes. Those changes in dielectric and rheological parameters seem to be related to a structural change occurring in the polyaniline organic dispersion systems while increasing temperature. An interesting correlation between permittivity and viscosity was obtained.
PACS: 77.22.Gm – Dielectric loss and relaxation / 77.84.Jd – Polymers; organic compounds / 83.60.Fg – Shear rate dependent viscosity
© EDP Sciences, 2009
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