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Frequency Dependent Dielectric Permittivity Studies in Emeraldine Base and Weakly Doped Polyaniline and its Deriviatives

Published online by Cambridge University Press:  21 March 2011

Nicholas J. Pintoa ,
Ghanshyam P. Sinha  and
Fouad M. Aliev
Nicholas J. Pintoa
Affiliation:
Dept. of Phys. and Elect., Univ. of Puerto Rico, Humacao, PR 00791, USA
Ghanshyam P. Sinha
Affiliation:
Dept. of Physics, Univ. of Puerto Rico, Rio Piedras, PR 00931, USA
Fouad M. Aliev
Affiliation:
Dept. of Physics, Univ. of Puerto Rico, Rio Piedras, PR 00931, USA
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Abstract

We report on a study of the complex dielectric permittivity in polyaniline (PAN), poly-o-toluidine (POT) and poly-o-ethylaniline (OPEA) in the undoped and weakly doped state in the frequency range 1 mHz upto 1 MHz. The doping concentration defined as y=[C1-]/[N] was chosen so that 0 ≤ y ≤ 0.07. OPEA with y=0.50 was also investigated. The objective of this work was to investigate the contribution of the mobile charge defects (polarons and bipolarons) on the conductivity and dielectric relaxation at such low doping levels. The three samples were chosen so as to compare the effects of introducing larger interchain disorder while maintaining a similar conduction mechanism. In all samples studied we observe the presence of a dielectric relaxation mechanism and the relaxation times depend on the doping level and disorder. The presence of a larger number of polarons as the doping level is increased leads to multiple paths for the system to relax leading to progressively non Debye like relaxation process. The results are interpreted in terms of creation and annihilation of polarons and bipolarons and their subsequent diffusion.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 598: Symposium BB – Electrical, Optical, & Magenetic Properties...V , 1999 , BB3.26
Copyright
Copyright © Materials Research Society 1999

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