Analytical modeling of the electrical conductivity of CNT-filled polymer nanocomposites
Analytical modeling of the electrical conductivity of CNT-filled polymer nanocomposites
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DOI：
10.1177/10812865231225483
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发表时间：
2024-02
影响因子：
2.6
通讯作者：
Masoud Ahmadi;Prashant Saxena
中科院分区：
文献类型：
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作者：
Masoud Ahmadi;Prashant Saxena
大多数聚合物绝缘体的导电性可以通过引入一小部分导电纳米填料来大幅提高。从细胞超材料到应变传感器，这些纳米复合材料有着广泛的工程应用。在这项工作中，我们提出了一个数学模型来预测碳纳米管/聚合物纳米复合材料的有效电导率，考虑碳纳米管的电导率、尺寸、体积分数和排列。Eshelby的经典等效包合方法（EIM）被推广用于解释电子跳跃——碳纳米管电子传递的关键机制，并通过实验数据进行了验证。采用填料取向极限角和概率分布函数两种测量方法来控制复合材料中CNTs的排列。模拟结果表明，当角度从均匀随机分布减小到完全排列状态时，横向电导率显著降低，而纵向电导率对角度变化的敏感性较低。此外，CNTs以非均匀概率分布函数分布会导致纵向电导率增加，横向电导率降低，并且随着CNTs体积分数的增加，这种差异变得更加明显。碳纳米管长度的减小降低了有效导电性，因为可用导电途径的数量减少了，而碳纳米管直径的减小则增加了导电性。
Electrical conductivity of most polymeric insulators can be drastically enhanced by introducing a small volume fraction [Formula: see text] of conductive nanofillers. These nanocomposites find wide-ranging engineering applications from cellular metamaterials to strain sensors. In this work, we present a mathematical model to predict the effective electrical conductivity of carbon nanotubes (CNTs)/polymer nanocomposites accounting for the conductivity, dimensions, volume fraction, and alignment of the CNTs. Eshelby’s classical equivalent inclusion method (EIM) is generalized to account for electron-hopping—a key mechanism of electron transport across CNTs, and is validated with experimental data. Two measurements, namely, the limit angle of filler orientation and the probability distribution function, are used to control the alignment of CNTs within the composites. Our simulations show that decreasing the angle from a uniformly random distribution to a fully aligned state significantly reduces the transverse electrical conductivity, while the longitudinal conductivity shows less sensitivity to angle variation. Moreover, it is observed that distributing CNTs with non-uniform probability distribution functions results in an increase in longitudinal conductivity and a decrease in transverse conductivity, with these differences becoming more pronounced as the volume fraction of CNTs is increased. A reduction in CNT length decreases the effective electrical conductivity due to the reduced number of available conductive pathways while reducing CNT diameter increases the conductivity.