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Electron spin resonance studies in the doped polyaniline PANI-AMPSA: Evidence for local ordering from linewidth features

Sitaram, V and Sharma, Ajay and Bhat, SV and Mizoguchi, K and Menon, Reghu (2005) Electron spin resonance studies in the doped polyaniline PANI-AMPSA: Evidence for local ordering from linewidth features. In: Physical Review B, 72 (3).

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Abstract

X-band electron spin resonance (ESR) of polyaniline (PANI) doped with 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPSA), at conductivity values of 90, 4, and 0.2 S/cm, has been investigated from 300 to 5 K.Free-standing films (30-40 mu m thick) of PANI were prepared by solution casting method. The spectra consist of two signals, one is broad (similar to 60 G) and the other is narrow (similar to 10 G), at nearly the same resonance field. The temperature variation of ESR susceptibility indicates a stronger Pauli component in the broad linesignal, as compared to the narrow signal, at all values of conductivity. Both linewidths are independent of the presence of O-2.The temperature variation of line widths is explained in terms of the quasi-two-dimensional (Q2D) model. These results suggest that in some regions the doped PANI chains have self-assembled Q2D structure, and the presence of a significant Pauli susceptibility indicates that the charge carriers are highly delocalized in these Q2D regions.

Item Type: Journal Article
Additional Information: Copyright for this article belongs to American Physical Society.
Keywords: conducting polymers;metallic states;transport;dynamics;epr;oxygen;esr
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 25 Aug 2005
Last Modified: 19 Sep 2010 04:19
URI: http://eprints.iisc.ernet.in/id/eprint/3563

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