کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1442009 | 1509430 | 2011 | 5 صفحه PDF | دانلود رایگان |
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.
Journal: Synthetic Metals - Volume 161, Issues 13–14, July 2011, Pages 1259–1263