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Conducting polymers; conductivity; polarons; polyaniline composites, 𝛾-Fe₂O₃.

Conducting polyaniline/𝛾-Fe₂O₃ (PANI/FE) composites have been synthesized using an in situ deposition technique by placing fine-graded 𝛾-Fe₂O₃ in a polymerization mixture of aniline. The composites are characterized by using scanning electron microscopy (SEM), X-ray diffraction (XRD) and infrared (IR) spectroscopy. The electrical properties such as d.c. and a.c. conductivities are studied by sandwitching the pellets of these composites between the silver electrodes. It is observed that the conductivity increases up to a composition of 20 wt.% of 𝛾-Fe₂O₃ in polyaniline and decreases thereafter. The initial increase in conductivity is attributed to the extended chain length of polyaniline, where polarons possess sufficient energy to hop between favourable sites. Beyond 20 wt.% of 𝛾-Fe₂O₃ in polyaniline, the blocking of charge carrier hop occurs, reducing conductivity values. The magnetic properties such as hysteresis characteristics and normalized a.c. susceptibility are also measured, which show a strong dependence on content of 𝛾-Fe₂O₃ in polyaniline. Because of superparamagnetic behaviour of these composites, they may find extensive technological applications, especially for absorbing and shielding applications in microwave frequencies.

Syed Khasim¹ S C Raghavendra² M Revanasiddappa³ K C Sajjan⁴ Mohana Lakshmi¹ Muhammad Faisal¹

1. Department of Physics, PES School of Engineering, Bangalore 560 100
2. Department of E&CE, PES School of Engineering, Bangalore 560 100
3. Department of Chemistry, PES School of Engineering, Bangalore 560 100
4. Department of Physics, Veerasaiva College, Bellary 583 101, India

Published

December 2011

Manuscript received

4 August 2009

Manuscript revised

10 November 2010