Abstract In situ, real-time polarized Raman spectroscopy was used to measure electrostatically induced carbon nanotube alignment in a polymer matrix. Discrete and reversible asymptotes of carbon nanotube G-band intensity were observed as a function of the applied electric field strength. It is proposed that as the electric field is increased, certain populations of carbon nanotubes attain sufficient alignment energy to overcome the randomizing thermal energy of the system. This is attributed to the electrostatic torque being a function of nanotube length, a relation that has been shown for dielectric rods and is extended here to carbon nanotubes. Nanotube batches of varying length distributions (hundreds of nanometers to micron-length) were created with different amounts of sonication energy. These distributions were quantified with atomic force microscopy measurements, and a model was developed relating these length distributions to the change in nanotube alignment at various electric field strengths. Nanotube polarizabilities determined from the model ( α = 10 − 30 − 10 − 32 F ⋅ m 2 ) were consistent with previously reported values. The effects of processing parameters such as sonication on the degree of achievable alignment as well as its implications are also discussed.

中文翻译：

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静电诱导碳纳米管排列的长度依赖性

摘要 原位实时偏振拉曼光谱用于测量聚合物基质中静电诱导的碳纳米管排列。作为外加电场强度的函数，观察到碳纳米管 G 带强度的离散和可逆渐近线。提出随着电场增加，某些碳纳米管群获得足够的排列能以克服系统的随机化热能。这归因于静电扭矩是纳米管长度的函数，这种关系已在介电棒中显示，并在此处扩展到碳纳米管。不同长度分布（数百纳米到微米长度）的纳米管批次是用不同量的超声能量产生的。这些分布通过原子力显微镜测量进行量化，并开发了一个模型，将这些长度分布与不同电场强度下纳米管排列的变化联系起来。由模型确定的纳米管极化率 (α = 10 − 30 − 10 − 32 F ⋅ m 2 ) 与先前报告的值一致。还讨论了处理参数（如超声处理）对可实现对齐程度的影响及其影响。