Article ID Journal Published Year Pages File Type
1442009 Synthetic Metals 2011 5 Pages PDF
Abstract

The modification of the ac conductivity and the complex permittivity of conducting polypyrrole was monitored throughout a two years thermal aging at 343 K. Reduction of the cross-over frequency is correlated with the degradation of dc-conductivity, while the ac conductivity region corresponding to the so-called ‘universal’ dielectric relaxation remains practically insensitive during the first year of ageing, which implies a collective co-operativity among multiple degradation processes that yield a practically time-independent effective disordered environment. A broad dielectric loss peak recorded in fresh specimens splits into two distinct relaxations for intermediate stages of the annealing process. The aging-time evolution of the dc component and the relaxations are qualitatively analysed and time constants are determined.

► The dispersive region of the dc conductivity of conducting polypyrrole is practically invariant to one year thermal ageing. ► Cross-over frequency links to the dc conductivity. ► Dielectric loss peak splits into two components within two years thermal ageing.

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Physical Sciences and Engineering Materials Science Biomaterials
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