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The ageing of polypyrrole nanotubes synthesized with methyl orange
European Polymer Journal ( IF 6 ) Pub Date : 2017-11-01 , DOI: 10.1016/j.eurpolymj.2017.08.052
Martin Varga , Dušan Kopecký , Jitka Kopecká , Ivo Křivka , Jan Hanuš , Alexander Zhigunov , Miroslava Trchová , Martin Vrňata , Jan Prokeš

Abstract The process of ageing of polypyrrole is accompanied by gradual changes in its chemical composition, protonation level and charge transport mechanism. Although these changes are often limiting for practical application of polypyrrole, they are still far from being understood. In our contribution, natural ( i.e. ageing at room temperature) and accelerated ageing (at 120 °C) of polypyrrole nanotubes were studied. Natural ageing for about 3 year timespan lead to relative decrease of sample conductivity to about 0.2 of its initial σ 0 value. Accelerated ageing caused a dramatic decrease of 7 orders of magnitude after about 1000 h accompanied by partial deprotonation and backbone oxidation as confirmed by infrared, Raman and XPS spectroscopy and elemental analysis. Occurrence of crystalline domains was attributed to residual methyl orange and was not affected by ageing. The presence of methyl orange was found crucial for improving stability of sample conductivity; it caused about 4 orders of magnitude enhanced conductivity when compared with polypyrrole without methyl orange. In macroscopic scale the conductivity loss was found to be a spatially homogeneous process as revealed by electrical tomography. With increasing ageing time, besides gradual degradation on microstructural level, a qualitative change of charge transport mechanism was found.

中文翻译:

甲基橙合成聚吡咯纳米管的老化

摘要 聚吡咯的老化过程伴随着其化学成分、质子化水平和电荷传输机制的逐渐变化。尽管这些变化往往限制了聚吡咯的实际应用,但它们仍远未得到理解。在我们的贡献中,研究了聚吡咯纳米管的自然老化(即在室温下老化)和加速老化(在 120 °C 下)。约 3 年时间跨度的自然老化导致样品电导率相对降低至其初始 σ 0 值的约 0.2。红外、拉曼和 XPS 光谱和元素分析证实,加速老化导致约 1000 小时后显着下降 7 个数量级,并伴有部分去质子化和骨架氧化。结晶域的出现归因于残留的甲基橙并且不受老化的影响。发现甲基橙的存在对于提高样品电导率的稳定性至关重要;与不含甲基橙的聚吡咯相比,它使电导率提高了大约 4 个数量级。在宏观尺度上,电导率损失被发现是一个空间均匀的过程,正如电断层扫描所揭示的那样。随着老化时间的增加,除了微观结构水平上的逐渐退化外,还发现电荷传输机制发生了质的变化。在宏观尺度上,电导率损失被发现是一个空间均匀的过程,正如电断层扫描所揭示的那样。随着老化时间的增加,除了微观结构水平上的逐渐退化外,还发现电荷传输机制发生了质的变化。在宏观尺度上,电导率损失被发现是一个空间均匀的过程,正如电断层扫描所揭示的那样。随着老化时间的增加,除了微观结构水平上的逐渐退化外,还发现电荷传输机制发生了质的变化。
更新日期:2017-11-01
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