Modeling the Electromagnetic Scattering Characteristics of Carbon Nanotube Composites Characterized by 3D Tomographic Transmission Electron Microscopy

Published

May 7, 2020

Author(s)

Ahmed M. Hassan, Md Khadimul Islam, Spencer On, Bharath Natarajan, Itai Stein, Noa Lachman, Estelle Cohen, Brian L. Wardle, Renu Sharma, James Alexander Liddle, Edward Garboczi

Abstract

In nearly all prior modeling studies of the electromagnetic properties of carbon nanotube (CNT) composites, the three-dimensional (3D) shape and spatial distribution of the CNTs in the composite were unknown. Therefore, simplifying assumptions had to be made regarding the CNT morphology and spatial organization. The effect of such assumptions on the electromagnetic response of CNT composites has not been quantified. Here, we quantify the effect of such assumptions using experimentally-characterized 3D CNT maps. Recently, electron tomography and image analysis has advanced to the point of being able to generate such maps of multi-walled carbon nanotube (MWCNT) distributions with sub-nanometer resolution. The electromagnetic responses of the mapped 3D structures of aligned-CNT polymer nanocomposites were calculated using both full-wave electromagnetic solvers and dilute limit effective medium approximations for multiple sets of CNT intrinsic conductivities. The results show that the electromagnetic response calculated using these two methods differs significantly. The full-wave solution shows additional resonances in the electromagnetic response that emerge at frequencies lower than half of the resonance frequencies calculated using the dilute limit effective medium approximation. This difference is due to the strong electromagnetic coupling between the MWCNTs in the sample that are in close proximity, within five CNT radii, of each other. The full-wave analysis presented in this work quantifies the limitations of the effective medium approximation and, therefore, will lead to a more accurate understanding of the electromagnetic response of CNT composites.

Citation

IEEE Open Journal of Antennas and Propagation

Volume

1

Pub Type

Journals

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DOI Link

Keywords

carbon nanotube, shape, electron tomography, electromagnetics, resonances, dilute limit

Citation

Hassan, A. , Islam, M. , On, S. , Natarajan, B. , Stein, I. , Lachman, N. , Cohen, E. , Wardle, B. , Sharma, R. , Liddle, J. and Garboczi, E. (2020), Modeling the Electromagnetic Scattering Characteristics of Carbon Nanotube Composites Characterized by 3D Tomographic Transmission Electron Microscopy, IEEE Open Journal of Antennas and Propagation, [online], https://doi.org/10.1109/OJAP.2020.2987879 (Accessed July 27, 2024)