Department of Chemistry, National Institute of Technology , Durgapur, WB India 713209.
Department of Materials Engineering, Indian Institute of Science , Bangalore, India 560012.
ACS Appl Mater Interfaces. 2017 Jan 25;9(3):3030-3039. doi: 10.1021/acsami.6b14853. Epub 2017 Jan 13.
To minimize electromagnetic (EM) pollution, two key parameters, namely, intrinsic wave impedance matching and intense absorption of incoming EM radiation, must satisfy the utmost requirements. To target these requirements, soft conducting composites consisting of binary blends of polycarbonate (PC) and poly(vinylidene fluoride) (PVDF) were designed with doped multiwalled carbon nanotubes (MWCNTs) and a three-dimensional cross-linked graphene oxide (GO) framework doped with ferrite nanoparticles. The doping of α-MnO onto the MWCNTs ensured intrinsic wave impedance matching in addition to providing conducting pathways, and the ferrite-doped cross-linked GO facilitated the enhanced attenuation of the incoming EM radiation. This unique combination of magnetodielectric coupling led to a very high electromagnetic shielding efficiency (SE) of -37 dB at 18 GHz, dominated by absorption-driven shielding. The promising results from the composites further motivated us to rationally stack individual composites into a multilayer architecture following an absorption-multiple reflection-absorption pathway. This resulted in an impressive SE of -57 dB for a thin shield of 0.9-mm thickness. Such a high SE indicates >99.999% attenuation of the incoming EM radiation, which, together with the improvement in structural properties, validates the potential of these materials in terms of applications in cost-effective and tunable solutions.
为了最小化电磁 (EM) 污染，两个关键参数，即固有波阻抗匹配和入射 EM 辐射的强烈吸收，必须满足最高要求。为了满足这些要求，设计了由聚碳酸酯 (PC) 和聚偏二氟乙烯 (PVDF) 的二元共混物组成的软导电复合材料，其中掺杂了多壁碳纳米管 (MWCNTs) 和掺杂了铁氧体纳米粒子的三维交联氧化石墨烯 (GO) 框架。MWCNTs 上掺杂的 α-MnO 不仅提供了导电途径，还确保了固有波阻抗匹配，而铁氧体掺杂的交联 GO 则促进了入射 EM 辐射的增强衰减。这种独特的磁电耦合组合导致在 18GHz 时具有非常高的电磁屏蔽效率 (SE)，为-37dB，主要由吸收驱动的屏蔽作用。复合材料的有希望的结果进一步促使我们按照吸收-多次反射-吸收的途径将单个复合材料合理地堆叠成多层结构。这导致 0.9 毫米厚的薄屏蔽层的 SE 达到-57dB。如此高的 SE 表示入射 EM 辐射衰减>99.999%，这与结构性能的提高一起，验证了这些材料在具有成本效益和可调节解决方案的应用中的潜力。
