Electric fields have been shown to induce orientation of CNTs in a polymer matrix along the direction of the applied field. When using a DC field, the CNTs also migrate between the two electrodes, resulting in a nonuniform CNT concentration across the composite sample and impacting the strengthening effect gained from the CNT alignment. In this study, we applied a DC electric field to a single-walled carbon nanotube (SWCNT)/epoxy solution and investigated the migration kinetics at different temperatures (34.0–56.6 °C) by tracking the real-time changes of SWCNT concentration. The SWCNTs were found to migrate from the negative electrode to the positive electrode at a constant speed. The rate of CNT migration increases with temperature and follows an Arrhenius relationship. The activation energy (83.3–87.7 kJ/mole) was comparable to the activation energy for the viscous flow of the neat epoxy, indicating the viscosity of the polymer melt is the main factor affecting the migration. The migration process and the resulting CNT concentration gradient across the sample are a function of temperature and time enabling control of the spatial distribution of the CNTs and the selective enhancement of electrical, mechanical and thermal properties of CNT/polymer composites.

中文翻译：

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直流电场下环氧树脂中单壁碳纳米管迁移的温度依赖性

电场已被证明可诱导聚合物基质中的碳纳米管沿外加场的方向取向。当使用直流电场时，碳纳米管也会在两个电极之间迁移，导致复合材料样品中碳纳米管浓度不均匀，并影响碳纳米管排列所获得的强化效果。在这项研究中，我们将直流电场应用于单壁碳纳米管 (SWCNT)/环氧树脂溶液，并通过跟踪 SWCNT 浓度的实时变化来研究不同温度 (34.0–56.6 °C) 下的迁移动力学。发现 SWCNT 以恒定速度从负极迁移到正极。CNT 迁移的速率随温度增加并遵循阿伦尼乌斯 (Arrhenius) 关系。活化能 (83.3–87. 7 kJ/mol) 与纯环氧树脂粘性流动的活化能相当，表明聚合物熔体的粘度是影响迁移的主要因素。整个样品的迁移过程和由此产生的 CNT 浓度梯度是温度和时间的函数，能够控制 CNT 的空间分布并选择性增强 CNT/聚合物复合材料的电学、机械和热性能。