仿生构筑超薄MXene/CNC电磁屏蔽复合薄膜

高强电磁屏蔽薄膜材料在柔性器件、汽车电子和航空航天等领域具有广泛应用前景, 受珍珠母微纳米结构及其优异机械性能的启发, 利用简单的溶液共混及真空抽滤方法, 将纤维素纳米晶(CNC)和MXene混合, 经层层组装制备了高性能MXene基复合薄膜。结果表明: 薄膜的机械性能有了显著提高, 拉伸强度从18 MPa提高到57 MPa, 韧性从70 kJ/m ³提高到313 kJ/m ³, 同时保留了复合薄膜的高电导率(10 ⁴ S/m)和优异的电磁屏蔽性能, 厚度8 μm时可达40 dB以上。     

Ultrahigh Conductive Copper/Large Flake Size Graphene Heterostructure Thin‐Film with Remarkable Electromagnetic Interference Shielding Effectiveness

To guarantee the normal operation of next generation portable electronics and wearable devices, together with avoiding electromagnetic wave pollution, it is urgent to find a material possessing flexibility, ultrahigh conductive, and superb electromagnetic interference shielding effectiveness (EMI SE) simultaneously. In this work, inspired by a building bricks toy with the interlock system, we design and fabricate a copper/large flake size graphene (Cu/LG) composite thin film (≈8.8 μm) in the light of high temperature annealing of a large flake size graphene oxide film followed by magnetron sputtering of copper. The obtained Cu/LG thin‐film shows ultrahigh thermal conductivity of over 1932.73 (±63.07) W m^?1 K^?1 and excellent electrical conductivity of 5.88 (±0.29) × 10⁶ S m^?1. Significantly, it also exhibits a remarkably high EMI SE of over 52 dB at the frequency of 1–18 GHz. The largest EMI SE value of 63.29 dB, accorded at 1 GHz, is enough to obstruct and absorb 99.99995% of incident radiation. To the best of knowledge, this is the highest EMI SE performance reported so far in such thin thickness of graphene‐based materials. These outstanding properties make Cu/LG film a promising alternative building block for power electronics, microprocessors, and flexible electronics.     

电磁屏蔽功能涂料研究进展

首先介绍电磁屏蔽材料的屏蔽方式和电磁屏蔽原理,然后,对目前常用的各种电磁屏蔽填料的功能特点和应用情况进行了分析,在此基础上,对电磁屏蔽涂料的制备方法、电磁屏蔽涂料的导电机理以及影响电磁屏蔽性能的因素进行了综合分析,对电磁屏蔽涂料的应用发展方向进行了展望。     

层状PPGr/PP复合材料的结构和电磁屏蔽性能

利用共挤出设备,制备了导电层(石墨填充聚丙烯PPGr)和绝缘层(聚丙烯PP)叠合的层状复合物,同时制备了PPGr普通共混物。比较了层状材料与普通共混材料在结构形态、电学性能、力学性能和电磁屏蔽性能方面的差异。研究发现,普通共混物电阻率为2.04×103Ω.cm时,在低频区(500 MHz~2 GHz)和中间频段区(2 GHz~18 GHz)内的最大屏蔽值都为34dB,而层状材料电阻率为2.79×105Ω.cm时,在上述频率区间的屏蔽效果分别达到49dB和56dB。力学性能测试表明层状材料的断裂伸长率和拉伸强度也优于普通共混材料。文中提出了层状复合物中电磁波的内部多重反射机理来解释这一实验现象。     

聚苯胺复合薄膜的电磁屏蔽及吸波性能

电磁屏蔽和吸波是导电高聚物的重要应用领域之一.本文总结了目前聚苯胺复合薄膜的基本制备方法,如原位聚合法、共混法、层层自组装法,介绍了表征聚苯胺复合薄膜电磁屏蔽效能和吸波性能的方法,阐述了其在上述领域中的应用,指出了聚苯胺复合薄膜未来需要研究与解决的问题.     

银盐方式等离子显示器（PDP）用电磁波屏蔽膜的开发

等离子显示器（PDP）的基本工作原理是基于密封在特制的玻璃管中的氦、氙等惰性气体在高电压下产生等离子体，进行放电并放射紫外线激发管壁上的荧光物质发出蓝、绿、红三原色光线构成图像，而图像的颜色和亮度则由经过调制的脉冲电流控制，后者会同时产生电磁波干扰，影响周边环境，本文介绍富士公司开发的一种用传统银盐感光材料制作的电磁波屏蔽膜，可有效地消除PDP工作时产生的不良电磁波。     

金属纤维填充聚合物复合材料的导电性能和电磁屏蔽性能

以不锈钢纤维作为填料,分别与ＡＢＳ和ＰＰ两种聚合物复合制得了电磁屏蔽用导电性高分子复合材料。通过研究复合材料导电性能和电磁屏蔽性能与纤维含量的关系,发现结晶性的ＰＰ基体比无定形ＡＢＳ基体所需的纤维临界填充量低,同时ＳＳＦ／ＰＰ的屏蔽效果高于ＳＳＦ／ＡＢＳ复合材料;此外,结果还表明这类复合材料对电磁波的屏蔽效果以吸收损耗为主,反射损耗量较小。     

可用于包装的纤维素基电磁屏蔽材料研究进展

目的 为推动可用于包装的纤维素基电磁干扰(Electromagnetic Interference,EMI)屏蔽材料更深入的研究,综述一些具有包装材料潜质和EMI屏蔽功能的纤维素基薄膜、织物和气凝胶的最新研究进展。方法 主要介绍纤维素基薄膜、织物和气凝胶等3类EMI屏蔽材料的制备方法、EMI屏蔽性能、多功能性和在包装上应用的潜力。结果 当下纤维素基EMI屏蔽材料表现出令人满意的EMI屏蔽效能(EMI Shielding Effectiveness, EMI SE)和力学性能,有望作为包装材料。同时一些材料还显示出抗菌、隔热、抗冲击等特性,使得这些材料能在复杂的场景下应用。结论 通过合理的设计,纤维素基EMI屏蔽材料可拥有优异的EMI屏蔽性能、出色的力学性能和良好的耐用性。归因于上述优势和绿色可降解的特性,这类材料有望在未来取代传统的EMI屏蔽包装材料,然而这些材料通常需要精细的制备工艺,材料的量产和实际应用依然是亟待解决的问题。     

Nanoengineering Natural Leather for Dynamic Thermal Management and Electromagnetic Interference Shielding

Unpredictable and extreme weather conditions, along with increasing electromagnetic pollution, have resulted in a significant threat to human health and productivity, causing irreversible damage to society's well-being and economy. However, existing personal temperature management and electromagnetic protection materials lack adaptability to dynamic environmental changes. To address this, a unique asymmetric bilayer leather/a-MWCNTs/CA fabric is developed by vacuum-infiltrating interconnected a-MWCNTs networks into natural leather's microfiber backbone and spraying porous acetic acid (CA) on the reverse side. Such fabric achieves simultaneous passive radiation cooling, heating, and anti-electromagnetic interference functions without external energy input. The fabric's cooling layer has high solar reflectance (92.0%) and high infrared emissivity (90.2%), providing an average subambient radiation cooling effect of 10 °C, while the heating layer has high solar absorption (98.0%), enabling excellent passive radiative heating and effective compensation for warming via Joule heating. Additionally, the fabric's 3D conductive a-MWCNTs network provides electromagnetic interference shielding effectiveness of 35.0 dB mainly through electromagnetic wave absorption. This multimode electromagnetic shielding fabric can switch between cooling and heating modes to adapt to dynamic cooling and heating scenarios, providing a new avenue for sustainable temperature management and electromagnetic protection applications.     

具有泡孔结构的聚合物导电复合电磁屏蔽材料的制备方法评述

如今急剧增加的各种通信系统和高频电子器件导致电磁干扰现象和电磁辐射污染问题日益突出.具有泡孔结构的聚合物导电复合材料不仅具有易加工、耐化学腐蚀和性能可调的优势,其泡孔结构还可以进一步赋予材料轻质的优势,同时增强电磁波在泡孔内部的多重散射/反射衰减以提升材料对电磁波的吸收,已经成为高性能电磁屏蔽材料的研究热点之一.本文综...     

电磁屏蔽复合材料的屏蔽性能预测

建立了填充椭球颗粒电磁屏蔽复合材料等效电磁参数的物理模型,基于变分原理和电磁波传输理论推导出其电磁屏蔽性能的预测公式,计算了不同填充条件下复合材料的屏蔽效能及反射率,分析了填料显微结构特征(浓度、形状、尺寸、分布方式)对复合材料屏蔽性能的影响规律.结果表明,复合材料屏蔽效能和反射率随填料填充浓度、长径比的增加而增大;针形和片形填料优于球形填料且定向分布好于随机分布;材料的反射率在特定的填充浓度及填料尺寸下存在峰值。屏蔽效能的计算结果与实验上填充球形银包羰基铁和镀镍短碳纤维的屏蔽复合材料的测试数据拟合较好。     

Wetting‐Induced Climbing for Transferring Interfacially Assembled Large‐Area Ultrathin Pristine Graphene Film

Owing to inherent 2D structure, marvelous mechanical, electrical, and thermal properties, graphene has great potential as a macroscopic thin film for surface coating, composite, flexible electrode, and sensor. Nevertheless, the production of large‐area graphene‐based thin film from pristine graphene dispersion is severely impeded by its poor solution processability. In this study, a robust wetting‐induced climbing strategy is reported for transferring the interfacially assembled large‐area ultrathin pristine graphene film. This strategy can quickly convert solvent‐exfoliated pristine graphene dispersion into ultrathin graphene film on various substrates with different materials (glass, metal, plastics, and cloth), shapes (film, fiber, and bulk), and hydrophobic/hydrophilic patterns. It is also applicable to nanoparticles, nanofibers, and other exfoliated 2D nanomaterials for fabricating large‐area ultrathin films. Alternate climbing of different ultrathin nanomaterial films allows a layer‐by‐layer transfer, forming a well‐ordered layered composite film with the integration of multiple pristine nanomaterials at nanometer scale. This powerful strategy would greatly promote the development of solvent‐exfoliated pristine nanomaterials from dispersions to macroscopic thin film materials.     

不锈钢纤维填充电磁波屏蔽塑料的进展

综述了国际国内不锈钢纤维填充电磁波屏蔽塑料的进展状况,试制了 锈钢纤维填充ABS的电磁波屏蔽塑料。     

Highly Stretchable Polymer Composite with Strain-Enhanced Electromagnetic Interference Shielding Effectiveness

Polymer composites with electrically conductive fillers have been developed as mechanically flexible, easily processable electromagnetic interference (EMI) shielding materials. Although there are a few elastomeric composites with nanostructured silvers and carbon nanotubes showing moderate stretchability, their EMI shielding effectiveness (SE) deteriorates consistently with stretching. Here, a highly stretchable polymer composite embedded with a three-dimensional (3D) liquid-metal (LM) network exhibiting substantial increases of EMI SE when stretched is reported, which matches the EMI SE of metallic plates over an exceptionally broad frequency range of 2.65–40 GHz. The electrical conductivities achieved in the 3D LM composite are among the state-of-the-art in stretchable conductors under large mechanical deformations. With skin-like elastic compliance and toughness, the material provides a route to meet the demands for emerging soft and human-friendly electronics.     

聚吡咯在电磁屏蔽材料中的研究进展

介绍了电磁屏蔽的基本理论,综述了聚吡咯在电磁屏蔽领域的研究进展,以及其复合材料的屏蔽性能的表征方法,并展望了聚吡咯作为电磁屏蔽材料的发展趋势。     

Synergistic Effect of Aligned Graphene Nanosheets in Graphene Foam for High‐Performance Thermally Conductive Composites

Graphene shows a great potential for high‐performance thermally conductive composite applications because of its extremely high thermal conductivity. However, the graphene‐based polymer composites reported so far only have a limited thermal conductivity, with the highest thermal conductivity enhancement (TCE) per 1 vol% graphene less than 900%. Here, a continuous network of graphene foam (GF), filled with aligned graphene nanosheets (GNs), is shown to be an ideal filler structure for thermally conductive composite materials. Compared to previous reports, a clear thermal percolation is observed at a low graphene loading fraction. The GNs/GF/natural rubber composite shows the highest TCE of 8100% (6.2 vol% graphene loading) ever reported at room temperature, which gives a record‐high TCE per 1 vol% graphene of 1300%. Further analyses reveal a significant synergistic effect between the aligned GNs and 3D interconnected GF, which plays a key role in the formation of a thermal percolation network to remarkably improve the thermal conductivity of the composites. Additionally, the use of this composite for efficient heat dissipation of light‐emitting diode (LED) lamps is demonstrated. These findings provide valuable guidance to design high‐performance graphene‐based thermally conductive materials, and open up the possibility for the use of graphene in high‐power electronic devices.     

石墨烯负载氧化铁在电磁屏蔽中的应用研究

研究了石墨烯负载氧化铁的制备工艺条件和电磁性能,并对石墨烯负载氧化铁复合材料的电磁屏蔽性能进行了测试,结果表明,石墨烯负载氧化铁后,磁性能获得提升,复合粒子材料具有较好的电磁屏蔽性能。