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Materials with negative permittivity have attracted increasing attention with the development of metamaterials. Here, polyimide/multi-walled carbon nanotube (PI/MWCNT) percolating composites have been fabricated, and, interestingly, the Drude-type negative permittivity behavior is achieved as MWCNT content reached percolation threshold, which is attributed to the plasmonic state of delocalized electrons within the interconnected MWCNTs. In addition, conductivity of composites increases abruptly by almost three orders of magnitudes when MWCNT content reached 1 wt%. Meanwhile, the conduction mechanism changed, suggesting the electrical properties are related to percolation of composites. Moreover, reactance is discussed based on equivalent circuit analysis and the composite with negative permittivity shows inductive character. This work explored the regulation mechanism of negative permittivity in kHz regions and the obtained epsilon-negative metacomposites are promising for applications like electromagnetic shielding and wearable cloaks, etc.

Meta‐materials with fascinating dielectric behavior have drawn much attentions for their potential applications recently. Herein, percolating GR/PVDF composites consisting of GR sheets homogeneously dispersed in PVDF matrix are fabricated via hot‐pressing method in 20 Hz‐1 MHz frequency regions, of which simultaneously realizing negative permittivity with low percolation threshold. It’s demonstrated that negative permittivity of GR/PVDF composites are resulted from the low‐frequency plasma oscillation of free electrons, and a universal regulatory mechanism of Drude model is analyzed. At the same time, rapid formative 3D GR conductive networks contributed to the low percolation threshold (7.78wt%) of composites. Moreover, it is shown that electrical percolation occurred in samples as GR content exceeds percolation threshold, indicating a typical metal‐like behavior. In addition, the reactance is discussed according to the equivalent circuit analysis. This work constructed the meta‐composites with low filler content, which is benefit for practical applications in electromagnetic devices.This article is protected by copyright. All rights reserved.