Shrinking rate of conducting grains in HCl-protonated polyaniline, polypyrrole, and polypyrrole/polyaniline blends with their thermal aging
| Autor: | S. Sakkopoulos, P. Malkaj, N. Kyriakopoulos, Evangelos Vitoratos, Evangelos Dalas, T. Argyreas |
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| Rok vydání: | 2005 |
| Předmět: |
Conductive polymer
Materials science Polymers and Plastics Analytical chemistry Shell (structure) General Chemistry Polypyrrole Surfaces Coatings and Films law.invention Metal chemistry.chemical_compound chemistry Magazine Electrical resistivity and conductivity law visual_art Polyaniline Polymer chemistry Materials Chemistry visual_art.visual_art_medium Polymer blend |
| Zdroj: | Journal of Applied Polymer Science. 97:117-122 |
| ISSN: | 1097-4628 0021-8995 |
| DOI: | 10.1002/app.21738 |
| Popis: | The dc electrical conductivity (σ) of HCl-protonated polyaniline, polypyrrole, and their blends was measured from 80 to 300 K for thermal aging times between approximately 0 and 600 h. The thermal aging took place at 70°C under room atmosphere. The change of σ with the temperature (T) and the decrease of σ with the thermal aging time (t) are consistent with a granular metal type structure, in which conductive grains are randomly distributed into an insulating matrix. Aging makes the grains shrink in a corrosion-like process. From σ = σ(T) measurements the ratio s/d, where s is the average separation between the grains and d their diameter, as well as the rate d(s/d)/dt of their decrease with t were calculated. These revealed that the conductive grains consist of a shell, in which aging proceeds at a decreasing rate, and a central core, which is consumed at a much slower rate. Our measurements not only permitted the estimation of the shell thickness, which lies between 0 and 5 A, but also gave quantitative information about the quality of the shells and the cores from their aging rates. The shells are consumed with an average rate of d(s/d)/dt = 6.6 × 10−4 (h−1), which is about 5 times greater than the more durable cores. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 117–122, 2005 |
| Databáze: | OpenAIRE |
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