EMI Shielding Effectiveness of Carbon Nanotube BuckyPaper Nanocomposite/Foam Sandwich Structures

Carbon nanotubes are known for their exceptional mechanical, electrical and thermal properties. Nanotubes’ electrical properties will play a vital role in many critical applications, with EMI shielding as one of the more important applications. In this study, the authors examined the effectiveness of SWNT BuckyPaper films’ electromagnetic interference (EMI) shielding. Individual BuckyPaper films used in the research were only 15∼25μm thick with an area density of 0.0705 oz./ft² or 21.5g/m². Highly conductive SWNT BuckyPapers films were incorporated into foam sandwich structures. EMI tests revealed that the foam structures with a surface skin of two layers of randomly oriented BuckyPaper films achieved attenuation as great as 26 dB at 455–500 MHz or an average of 21 dB across the entire frequency range, compared to the pure foam control panel. At frequency ranges of 4GHz-18GHz, the foam sandwich samples with three layers SWNT BuckyPapers showed an EMI attenuation as high as 30dB across the entire frequency range. The results show that SWNT BuckyPaper materials offer a very promising lightweight technical solution for EMI shielding application. BuckyPapers can also easily be incorporated into conventional composite structures, which is critical for potential large scale application of SWNTs for multifunctional composites and structures.