Epsilon-negative behavior and its capacitance enhancement effect on trilayer-structured polyimide–silica/multiwalled carbon nanotubes/polyimide–polyimide composites

Abstract

Epsilon-negative materials show fascinating prospects in electronic components, such as coil-free inductors, stacked capacitors, and resonators, while extremely high negative permittivity at radio frequency blocks their further applications in electronic...

Enhancement of dielectric properties of acrylic resin elastomer‐based composites with SiO2 loaded carbon nanotubes

“…Fitting the conductivity data according to Equations () and () reveals that the f c of CNT/ARE and SiO 2 @CNT/ARE composite films are 2.60 and 3.41 vol%, respectively. Since SiO 2 acts as an insulator and reduces the electrical conductivity when loaded on the CNT, in addition, the SiO 2 on the CNT surface prevents direct contact with each other and delays the establishment of the conductive network inside the composite, 24,25 as can be seen according to Figure 4C, the conductivity of 2.41 vol% CNT/ARE is 2.62 × 10 −8 S/m, whereas the conductivity of 3.22 vol% SiO 2 @CNT/ARE after the SiO 2 loading is 1.22 × 10 −8 S/m. Furthermore, the SEM images of the fracture surface of the composite film illustrate that SiO 2 @CNT is more compatible with the ARE, and SiO 2 @CNT can be dispersed more homogeneously in the ARE, retarding the establishment of the conductive paths and improving the value of f c . where, σ , , and denote the DC conductivity, the volume fraction, and the percolation threshold of the composite, respectively 26 …”

Negative Capacitance in Nanocomposite Based on High-Density Polyethylene (HDPE) with Multiwalled Carbon Nanotubes (CNTs)

“…NC research generally concerns two types of devices and materials. The first type is based on semi-conductor devices and materials with precise periodic geometries [3][4][5][6][7][8][9][10][11][12]. Their main drawback is precisely that NC originates from their artificial periodic configuration and their size depends on the wavelength of the applied electromagnetic field, making it very difficult to change the shape or miniaturization and limiting their scalable manufacturing [1][2][3][4][5][6][7][8][9][10][11][12].…”

“…The first type is based on semi-conductor devices and materials with precise periodic geometries [3][4][5][6][7][8][9][10][11][12]. Their main drawback is precisely that NC originates from their artificial periodic configuration and their size depends on the wavelength of the applied electromagnetic field, making it very difficult to change the shape or miniaturization and limiting their scalable manufacturing [1][2][3][4][5][6][7][8][9][10][11][12]. The advent of nanotechnologies has opened up a whole new field of possibilities for a second type of material-i.e., nanocomposites-making it easier and more robust to fabricate randomly ordered multi-phase materials by dispersing and confining electroconductive nanoparticles in a matrix that is not necessarily electroconductive.…”

Realization of broadband index-near-zero modes in nonreciprocal magneto-optical heterostructures

“…Metamaterials (MMs) with fantastic electromagnetic characteristics have been an attractive topic in the past decades. Many different MMs such as negative-index MMs [10,11], hyperbolic metamaterials [12,13] and epsilon-negative MMs [14] were proposed by several research groups. Besides, the index-near-zero (INZ) MMs, including the epsilon-near-zero (ENZ) MMs with vanishing permittivity [15][16][17][18], the µ-near-zero MMs with vanishing permeability [19], double-near-zero (DNZ) MMs with both permittivity and permeability approach zero [20][21][22], and the INZ MMs proposed in the PhCs [23,24], are one of the research focus.…”