Functional nanomaterial embedded lightweight polymer composites have drawn considerable attention in wide ranges of industrial applications. In addition to telecommunication and aerospace utilities, microwave absorbing materials must possess fascinating properties that ensure excellent performance- from mechanical features to functionalities. Although conducting polymer composites containing magnetic nanofillers have been utilized widely, however, choosing the fillers from the library of nanoparticles and their effective dispersion inside the matrix may limit their usage in terms of performance, stability and durability. For breaking such bottleneck, herein we explored facile bottom-up synthetic procedure to fabricate different shapes (like spherical, cubic, cluster, flower) and size controlled Fe3O4 nanoparticles, and showed the effect of shape anisotropy and size that meet the criteria on above said properties in a model PC/PVDF blend with MWCNTs as a conducting nanofillers. The superior performance in terms of microwave attenuation and mechanical properties was reported for spherically shaped Fe3O4 nanomaterials. The excellent dispersibility of small-sized nanospheres was instrumental in improved consolidated loss tangent values, attenuation constant, and impedance matching and skin depth synergistically resulting in -38 dB at 18 GHz.

中文翻译：

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含铁氧体的软导电复合材料中的电磁屏蔽：尺寸和形状各向异性的关键作用

功能性纳米材料嵌入的轻质聚合物复合材料在广泛的工业应用中引起了相当大的关注。除电信和航空航天事业外，微波吸收材料还必须具有引人入胜的特性，以确保出色的性能-从机械特征到功能性。尽管包含磁性纳米填料的导电聚合物复合材料已被广泛使用，但是，从纳米颗粒库中选择填料及其在基体内的有效分散可能会限制其在性能，稳定性和耐用性方面的用途。为了克服这种瓶颈，我们在这里探索了一种自下而上的合成方法，以制造不同形状（如球形，立方体，簇状，花朵状）和尺寸受控的Fe3O4纳米颗粒，并显示了在具有MWCNTs作为导电纳米填料的PC / PVDF模型共混物中，形状各向异性和尺寸的影响符合上述特性的标准。据报道球形Fe3O4纳米材料在微波衰减和机械性能方面均具有优异的性能。小尺寸纳米球的出色分散性有助于改善合并损耗正切值，衰减常数，阻抗匹配和趋肤深度，从而在18 GHz时产生-38 dB的协同效应。