Abstract

Conducting polymer composites with suitable combination of two components in nanoscale are expected to facilitate wider applications of composites. In this study, polypyrrole (PPy)/multiwalled carbon nanotube (MWCNT) nanocomposites prepared by in situ chemical oxidative polymerization were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and UV–Vis spectroscopy. The electrical and dielectric properties were investigated using complex impedance technique. Complex dielectric permittivity, complex electric modulus and complex impedance variations were studied in the frequency range of 10 Hz–1 MHz. The dielectric attributes and conductivity data of different nanocomposites analyzed as a function of frequency revealed that the incorporation of MWCNT phase into polypyrrole matrix affects the electrical and dielectric properties of the composites. Humidity sensor measurements show that PPy/MWCNT can be effectively optimized as candidate for humidity detection. The nanocomposites were also studied for broadband EMI shielding applications by characterizing the materials in the 12‒18 GHz (Ku band) to understand the shielding properties. The absorption dominant shielding effectiveness (SE) observed in the range of ‒13 to ‒15 dB was stable with visible variation with varying concentration of MWCNT in PPy. The experimental results of dielectric characterization, humidity sensing and EMI shielding response reveal that PPy/MWCNT composite can be suitable multifunctional material for various applications.

中文翻译：

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多功能聚吡咯/多壁碳纳米管复合材料：介电、湿度传感和宽带EMI屏蔽特性

摘要

两种组分在纳米尺度上的适当组合的导电聚合物复合材料有望促进复合材料的更广泛应用。在这项研究中，通过 X 射线衍射 (XRD)、傅里叶变换红外光谱 (FTIR)、扫描电子显微镜 (SEM) 和紫外线对原位化学氧化聚合制备的聚吡咯 (PPy)/多壁碳纳米管 (MWCNT) 纳米复合材料进行了表征。 – 可见光谱。使用复阻抗技术研究了电和介电特性。在 10 Hz–1 MHz 的频率范围内研究了复介电常数、复电模量和复阻抗变化。作为频率函数分析的不同纳米复合材料的介电属性和电导率数据表明，将 MWCNT 相掺入聚吡咯基体会影响复合材料的电学和介电性能。湿度传感器测量表明，PPy/MWCNT 可以有效地优化为湿度检测的候选材料。还通过表征 12-18 GHz（Ku 波段）中的材料以了解屏蔽性能，研究了纳米复合材料的宽带 EMI 屏蔽应用。在 ‒13 到 ‒15 dB 的范围内观察到的吸收主导屏蔽效率 (SE) 是稳定的，随着 PPy 中 MWCNT 浓度的不同，可见变化。介电特性的实验结果，