Abstract Recently, polymer-based composites for electromagnetic interference (EMI) shielding materials have received considerable attention since the autonomous vehicle market is increasingly growing. However, the strategies for enhancing EMI shielding effectiveness (EMI SE) are limited to the increase of filler loading. Only few studies have been conducted on controlling fillers owing to the technical challenges. In this study, anisotropic EMI shielding properties of polymer-based composites were demonstrated and investigated. In order to control the orientation of reduced graphene oxide (RGO) in thermoplastic polyurethane (TPU), magnetic responsive RGO (Fe3O4@RGO) was synthesized for filler material. The orientation of Fe3O4@RGO was controlled in in-plane and out-of-plane direction by applying the magnetic field. For comparison with the aligned Fe3O4@RGO/TPU composites, random Fe3O4@RGO/TPU and random RGO/TPU composites were synthesized and characterized. The random Fe3O4@RGO/TPU composites showed 224% increased EMI SE over random RGO/TPU composites. The highest EMI SE, 250% improvement over random RGO/TPU composite, was observed in in-plane aligned Fe3O4@RGO composite among the four different composites. This could be attributed to improved electromagnetic wave (EM) loss by introducing magnetic nanoparticles, as well as enlarged effective reflection area of the aligned Fe3O4@RGO. Our results confirm that the orientation of fillers can play a key role in determining EMI SE in the composites. It can indicate that, if optimized, magnetically-responsive aligned polymer composites could significantly improve EMI SE of the composites by controlling the orientation of fillers, and also be a new solution to create anisotropic composites toward desirable properties.

中文翻译：

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具有磁响应排列的 Fe3O4 装饰的还原氧化石墨烯的聚合物基复合材料的各向异性电磁干扰屏蔽性能

摘要 近年来，随着自动驾驶汽车市场的日益增长，用于电磁干扰 (EMI) 屏蔽材料的聚合物基复合材料受到了广泛关注。然而，提高 EMI 屏蔽效果 (EMI SE) 的策略仅限于增加填料负载。由于技术挑战，关于控制填料的研究很少。在这项研究中，展示和研究了聚合物基复合材料的各向异性 EMI 屏蔽性能。为了控制还原氧化石墨烯 (RGO) 在热塑性聚氨酯 (TPU) 中的取向，合成了磁响应 RGO (Fe3O4@RGO) 作为填充材料。Fe3O4@RGO 的取向通过施加磁场控制在面内和面外方向。为了与对齐的 Fe3O4@RGO/TPU 复合材料进行比较，合成并表征了随机 Fe3O4@RGO/TPU 和随机 RGO/TPU 复合材料。与随机 RGO/TPU 复合材料相比，随机 Fe3O4@RGO/TPU 复合材料的 EMI SE 提高了 224%。在四种不同的复合材料中，在面内对齐的 Fe3O4@RGO 复合材料中观察到最高的 EMI SE，比随机 RGO/TPU 复合材料提高 250%。这可能归因于通过引入磁性纳米粒子来改善电磁波 (EM) 损失，以及排列的 Fe3O4@RGO 的有效反射面积扩大。我们的结果证实，填料的取向可以在确定复合材料中的 EMI SE 方面发挥关键作用。它可以表明，如果优化，