Tunable Negative Permittivity in Flexible Graphene/PDMS Metacomposites

Abstract

The flexible metacomposites with tunable negative permittivity have great potential in wearable cloaks, stretchable sensors, and thin-film capacitors, etc. In this paper, the flexible graphene/polydimethyl­siloxane (GR/PDMS) metacomposites with tunable negative permittivity were prepared by an in situ polymerization method. The ac conductivity behavior, dielectric property, and impedance performance of the resulting composites with different graphene mass ratios (0–4 wt %) were studied. With the increase of graphene, the conductive mechanism of the resulting composites changed from hopping conduction to electron conduction, along with the change of microstructure. When graphene content in the composites came up to 3 wt %, the negative permittivity conforming to Drude model was observed. Further investigation revealed that there is a corresponding relationship between the permittivity and the reactance. It is demonstrated that the inductive character is responsible for the negative permittivity, while the capacitive character results in the positive permittivity.

Graphene reinforced carbon fibers

“…The addition of CNTs also lowered the carbonization temperature, which can significantly reduce the energy consumption during CF manufacturing (28). Graphene, a single-layered two-dimensional (2D) carbon allotrope, demonstrates superior properties to CNTs, such as larger surface area, superior electron mobility, higher tensile strength, and Young's modulus, which make it ideal for various applications, such as energy storage, metamaterials, and reinforced composite materials (29)(30)(31)(32). Recently, graphene oxide (GO) liquid crystal, a derivate of graphene, was evaluated for the fabrication of CFs using various approaches, such as wet spinning, dry spinning, dry-jet wet spinning, electrophoretic self-assembly, and film shrinkage and twisting methods (33).…”

Colorimetric determination of amaranth followed enrichment and separation using buoyant adsorbents

“…It is of great significance for the detection of contaminants whose concentration is below the detection limits of common analytical instruments. Furthermore, this kind of composite may realize the negative permittivity behavior by doping (Sun et al 2019), and be functionalized for other applications, including metal-free energy storage systems (Zhang et al 2019b) and photodegradation (Song et al 2020).…”

Overview of Ionogels in Flexible Electronics

“…[1][2][3] There is an urgent need for flexible materials [4][5][6][7][8][9][10][11] that could be stretched, conductive and transparent. [12][13][14] Nowadays hydrogels [15,16] served as an ideal material with flexibility, [17,18] transparency [19,20] and ionic conductivity [21] following by dissolution of the corresponding ionic salts. [22,23] Various researches have been developed to use hydrogels as flexible sensors, [24][25][26] supercapacitors, [27] lithium batteries, [28] drug release, [29] actuators, [30] etc.…”