Three kinds of diamine monomers [ethylenediamine, butylenediamine and [Formula: see text]-phenylenediamine (PPD)] are adopted to cross-link carboxylated graphene (GP-COOH) sheets through filtration with a vacuum-assisted self-assembly technique, to fabricate highly conductive and excellent electromagnetic interference (EMI) shielding films. XRD spectroscopy of cross-linked graphene films exhibits higher interlayer [Formula: see text]-spacing than the GP-COOH film. Results of FTIR and XPS spectroscopies indicate that diamine monomers are chemically grafted to the GP-COOH sheets through nucleophilic substitution reactions. Compared with that of the GP-COOH film, electrical conductivity of the PPD-cross-linked graphene film (GP-PPD) is remarkably improved from 69.7[Formula: see text]S/cm to 248.6[Formula: see text]S/cm, attributed to the decrease of junction contact resistance between adjacent graphene sheets, nitrogen doping effect and repair of defects. Higher nitrogen content and C/O ratio are observed in the XPS spectra of the GP-PPD film, leading to higher electrical conductivity than the remaining two amine-modified graphene films. The GP-PPD film also demonstrates excellent EMI shielding performance, with EMI shielding effectiveness (SE) of 26.5 dB at a thickness of 12.5[Formula: see text][Formula: see text]m, which is also better than the others. The outstanding EMI performance of the PPD-cross-linked graphene film is mainly ascribed to the enhanced electrical conductivity and modified electronic structure with nitrogen doping.

中文翻译：

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通过与二胺单体反应制备具有交联结构的柔性 EMI 屏蔽材料的石墨烯薄膜

采用三种二胺单体[乙二胺、丁二胺和[分子式：见正文]-苯二胺（PPD）]，通过真空辅助自组装技术过滤交联羧化石墨烯（GP-COOH）片，制备高导电性和优异的电磁干扰 (EMI) 屏蔽膜。交联石墨烯薄膜的 XRD 光谱显示出比 GP-COOH 薄膜更高的层间 [公式：见正文]-间距。FTIR 和 XPS 光谱的结果表明，二胺单体通过亲核取代反应化学接枝到 GP-COOH 片上。与GP-COOH薄膜相比，PPD交联石墨烯薄膜（GP-PPD）的电导率由69.7[公式：见正文]S/cm显着提高到248.6[公式：见正文]S/厘米，归因于相邻石墨烯片之间的结接触电阻的降低、氮掺杂效应和缺陷的修复。在 GP-PPD 薄膜的 XPS 光谱中观察到更高的氮含量和 C/O 比，导致比其余两种胺改性石墨烯薄膜更高的电导率。GP-PPD薄膜也表现出优异的EMI屏蔽性能，在12.5[公式：见正文][公式：见正文]m的厚度下，EMI屏蔽效果（SE）为26.5 dB，也优于其他薄膜。PPD交联石墨烯薄膜出色的EMI性能主要归功于增强的导电性和氮掺杂修饰的电子结构。在 GP-PPD 薄膜的 XPS 光谱中观察到更高的氮含量和 C/O 比，导致比其余两种胺改性石墨烯薄膜更高的电导率。GP-PPD薄膜也表现出优异的EMI屏蔽性能，在12.5[公式：见正文][公式：见正文]m的厚度下，EMI屏蔽效果（SE）为26.5 dB，也优于其他薄膜。PPD交联石墨烯薄膜出色的EMI性能主要归功于增强的导电性和氮掺杂修饰的电子结构。在 GP-PPD 薄膜的 XPS 光谱中观察到更高的氮含量和 C/O 比，导致比其余两种胺改性石墨烯薄膜更高的电导率。GP-PPD薄膜也表现出优异的EMI屏蔽性能，在12.5[公式：见正文][公式：见正文]m的厚度下，EMI屏蔽效果（SE）为26.5 dB，也优于其他薄膜。PPD交联石墨烯薄膜出色的EMI性能主要归功于增强的导电性和氮掺杂修饰的电子结构。EMI屏蔽效能（SE）为26.5 dB，厚度为12.5[公式：见正文][公式：见正文]m，也优于其他。PPD交联石墨烯薄膜出色的EMI性能主要归功于增强的导电性和氮掺杂修饰的电子结构。EMI屏蔽效能（SE）为26.5 dB，厚度为12.5[公式：见正文][公式：见正文]m，也优于其他。PPD交联石墨烯薄膜出色的EMI性能主要归功于增强的导电性和氮掺杂修饰的电子结构。