• The cationic waterborne polyurethanes microspheres with Diels-Alder bonds were synthesized for the first time.

• The electrostatic attraction not only endows the composite with segregated structure to gain high electromagnetic-interference shielding effectiveness, but also greatly enhances mechanical properties.

• Efficient healing property was realized under heating environment.

Abstract

It is still challenging for conductive polymer composite-based electromagnetic interference (EMI) shielding materials to achieve long-term stability while maintaining high EMI shielding effectiveness (EMI SE), especially undergoing external mechanical stimuli, such as scratches or large deformations. Herein, an electrostatic assembly strategy is adopted to design a healable and segregated carbon nanotube (CNT)/graphene oxide (GO)/polyurethane (PU) composite with excellent and reliable EMI SE, even bearing complex mechanical condition. The negatively charged CNT/GO hybrid is facilely adsorbed on the surface of positively charged PU microsphere to motivate formation of segregated conductive networks in CNT/GO/PU composite, establishing a high EMI SE of 52.7 dB at only 10 wt% CNT/GO loading. The Diels–Alder bonds in PU microsphere endow the CNT/GO/PU composite suffering three cutting/healing cycles with EMI SE retention up to 90%. Additionally, the electrostatic attraction between CNT/GO hybrid and PU microsphere helps to strong interfacial bonding in the composite, resulting in high tensile strength of 43.1 MPa and elongation at break of 626%. The healing efficiency of elongation at break achieves 95% when the composite endured three cutting/healing cycles. This work demonstrates a novel strategy for developing segregated EMI shielding composite with healable features and excellent mechanical performance and shows great potential in the durable and high precision electrical instruments.

中文翻译：

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一种具有隔离导电网络结构的可修复和机械增强复合材料，用于高效电磁干扰屏蔽

• 首次合成了具有Diels-Alder键的阳离子水性聚氨酯微球。

• 静电引力不仅使复合材料具有偏析结构，从而获得较高的电磁干扰屏蔽效果，而且还大大提高了机械性能。

• 在加热环境下实现了高效的愈合性能。

抽象的

对于基于导电聚合物复合材料的电磁干扰 (EMI) 屏蔽材料而言，在保持高 EMI 屏蔽效率 (EMI SE) 的同时实现长期稳定性仍然具有挑战性，尤其是在受到外部机械刺激时，例如划痕或大变形。在此，采用静电组装策略设计了一种可修复和分离的碳纳米管（CNT）/氧化石墨烯（GO）/聚氨酯（PU）复合材料，具有优异可靠的EMI SE，甚至可以承受复杂的机械条件。带负电的 CNT/GO 杂化物很容易吸附在带正电的 PU 微球表面，促进在 CNT/GO/PU 复合材料中形成分离的导电网络，在仅 10 wt% 的 CNT/GO 负载下建立 52.7 dB 的高 EMI SE . PU 微球中的 Diels-Alder 键使 CNT/GO/PU 复合材料经受三个切割/愈合循环，EMI SE 保留率高达 90%。此外，CNT/GO 杂化物和 PU 微球之间的静电引力有助于增强复合材料的界面结合，从而产生 43.1 MPa 的高拉伸强度和 626% 的断裂伸长率。当复合材料经受三个切割/愈合循环时，断裂伸长率的愈合效率达到 95%。这项工作展示了一种开发具有可修复特性和优异机械性能的隔离 EMI 屏蔽复合材料的新策略，并在耐用和高精度电气仪器中显示出巨大的潜力。CNT/GO 杂化物和 PU 微球之间的静电吸引力有助于增强复合材料中的界面结合，从而产生 43.1 MPa 的高拉伸强度和 626% 的断裂伸长率。当复合材料经受三个切割/愈合循环时，断裂伸长率的愈合效率达到 95%。这项工作展示了一种开发具有可修复特性和优异机械性能的隔离 EMI 屏蔽复合材料的新策略，并在耐用和高精度电气仪器中显示出巨大的潜力。CNT/GO 杂化物和 PU 微球之间的静电吸引力有助于增强复合材料中的界面结合，从而产生 43.1 MPa 的高拉伸强度和 626% 的断裂伸长率。当复合材料经受三个切割/愈合循环时，断裂伸长率的愈合效率达到 95%。这项工作展示了一种开发具有可修复特性和优异机械性能的隔离 EMI 屏蔽复合材料的新策略，并在耐用和高精度电气仪器中显示出巨大的潜力。