Enhancing Electromagnetic Interference Shielding Effectiveness of Polymer Nanocomposites by Modifying Subsurface Carbon Nanotube Distribution

Abstract

Enhancing electromagnetic interference (EMI) shielding effectiveness (SE) of polymer nanocomposites (PNCs) relies on modification of carbon nanotube (CNT) distributions achieved by controlling fabrication parameters. However, establishing correlations between fabrication parameters, CNT distributions, and SE properties is a challenging task due to the restrictions on the traditionally implemented CNT network detection techniques and qualitative CNT distribution descriptors. Herein an SE enhancing methodology for single‐walled carbon nanotubes/polyimide (SWCNT/PI) nanocomposite films in which AC sinusoidal voltages (5, 10, and 15 V at 10 Hz) are applied during processing to control CNT distribution is presented. The prepared nanocomposite samples are characterized using scattering‐parameter measurements for SE estimation and second‐harmonic electrostatic force microscopy (2ωe‐EFM) for subsurface CNT network detection. The detected CNT networks are described by implementing the uniform‐distancing (CNTD), agglomeration (CNTA), and shielding (CNTS) quantitative CNT descriptors. The results show enhancement on the nanocomposite SE values with the increment on the CNTS descriptor, which increases with lower applied voltages during processing. The SWCNT/PI nanocomposite studied herein exhibits a predominant absorption SE mechanism, which makes it a candidate for potential EMI absorber material applications. The proposed methodology represents an alternative for the quantitative assessment of correlations between PNC properties, CNT distributions, and fabrication parameters.

Printable Aligned Single-Walled Carbon Nanotube Film with Outstanding Thermal Conductivity and Electromagnetic Interference Shielding Performance

“…In contrast, single-walled CNTs (SWCNTs) have been widely studied and exhibit peak electrical conductivity exceeding other carbon nanomaterials due to their electronic structure derived from 1 3 the carbon sp 2 lattice hybridization [19,26,33]. Despite the increased difficulty in dispersing SWCNTs due to their ultrathin nature as compared to MWCNTs, a superior EMI shielding performance is predicted for SWCNTs [34][35][36][37][38]. Presently, either suspension-based deposition such as vacuum filtration or chemical vapor deposition (CVD) methods are employed to prepare freestanding SWCNT films [39,40].…”

A Carbon Composite Film with Three-Dimensional Reticular Structure for Electromagnetic Interference Shielding and Electro-Photo-Thermal Conversion

“…Therefore, adding carbon materials to CPCs to improve their conductivity and enhance the electromagnetic shielding performance has become a research hotspot in recent years. Octavio Alejandro Castañeda-Uribe et al controlled the distribution of the carbon nanotubes by applying a sinusoidal AC voltage to enhance electromagnetic shielding performance (EMI SE 77 dB) for single-walled carbon nanotubes/polyimide (SWCNT/PI) nanocomposite films [ 12 ]. Ziming Shen et al backfilled epoxy into wood-derived carbon scaffolds to acquire high electromagnetic interference shielding effectiveness (EMI SE 27.8 dB) and thermal conductivity (TC) [ 13 ].…”