With the increasing application of barium titanate (BaTiO₃) in polyvinylidene fluoride (PVDF), the evaluation of its dielectric properties has attracted the attention of many frontier scholars. In this paper, from the theoretical point of view, the effects of the aspect ratio and the concentrations of BaTiO₃ nanowires on macroscopic dielectric properties were studied by the finite element method. Depending on the calculation results, some conclusions had been obtained: First, it was found that the effect of higher aspect ratios of nanowires on the effective permittivity of the composites was not significant when the aspect ratio of the nanowire filler exceeded 20. Second, when the permittivity of the BaTiO₃ nanowires reaches about 3000, as the permittivity of the filler increases, the rate of change of the effective permittivity of the composite material gradually slows down, which indicates that nanowires with higher permittivity have little influence on the effective permittivity of the composites. Finally, by comparing with permittivity data of BT/PVDF composites in the literature, it was found that the simulation results have good consistency with the experimentally measured values. The above-mentioned results have shown that the composite may exhibit good dielectric properties at a low concentration (<30 vol. %) and low permittivity filler. Moreover, the electrostatic field can roughly represent the electric field of a low-concentration composite under a certain electric field strength.

中文翻译：

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BaTiO3纳米线对PVDF复合材料有效介电常数的影响

随着钛酸钡（BaTiO ₃）在聚偏二氟乙烯（PVDF）中的日益广泛的应用，对其介电性能的评估吸引了许多前沿学者的关注。本文从理论的角度，通过有限元方法研究了长径比和BaTiO ₃纳米线的浓度对宏观介电性能的影响。根据计算结果，得出了一些结论：首先，发现当纳米线填料的长径比超过20时，较高的长径比对复合材料的有效介电常数的影响并不显着。 BaTiO ₃的介电常数纳米线达到约3000，随着填料介电常数的增加，复合材料的有效介电常数的变化速率逐渐减慢，这表明具有较高介电常数的纳米线对复合材料的有效介电常数几乎没有影响。最后，通过与文献中BT / PVDF复合材料的介电常数数据进行比较，发现模拟结果与实验测量值具有良好的一致性。上述结果表明，该复合物可以在低浓度（＜30体积％）和低介电常数的填料下表现出良好的介电性能。此外，静电场可以粗略地表示在一定电场强度下低浓度复合材料的电场。