3D simulation of composite filled by straight CNTs.
Schematic view of the organization of the composite (left) and the associated electrical network (right).
Electrical percolation threshold as function of aspect ratio. The curves are theoretical bounds of the critical volume fraction calculated with the excluded volume theory. In the inset, the references concerning the results from other experimental or simulation studies are indicated.
Electrical conductivity of the randomly oriented CNT-filled composites as a function of volume fraction for two different aspect ratios. A line “to guide the eye” between the simulation points (red and green markers) is introduced to highlight the power law of the percolation theory. The inset shows the log-log plot of the electrical conductivity of the composite as a function of (p-pc ) with a linear fit.
Effect of CNTs content on electrical parameters of composite.
Dependence of the number of percolation paths with the volume fraction of CNTs.
Resistance due to tunneling effect as function of the thickness of insulating resin at different values of height of barrier.
The dominant effect of the thickness resin on the conductivity of composites.
Effect of height of barrier variations on the electron tunneling for different length of distance.
Electrical composite conductivity as a function of the height of barrier for epoxy in a nanocomposite with different volume fractions of CNTs.
Variation of electrical conductivity as a function of CNT intrinsic conductivity in a nanocomposite with different volume fractions of CNTs.
Variation of the real and imaginary part of the complex permittivity as function of filler loading.
Frequency dependence of the impedance modulus (in db) and phase angle (in deg) for the composite model with different filler concentrations and with two different values of energy barrier.
Frequency dependent conductivity for composites with different CNT loadings and two different energy of barrier.
Logarithmic plot of conductivity against p−1/3. The dashed line is a linear fit of the dc conductivity obtained in this simulation study.
Master curve σ/ σDC as a function of apf. The dashed line is a fit of the ac data obtained with a linear interpolation from the frequency ω0 at which the ac conductivity overcomes σDC by a factor , i.e., σ(ω0 ) = σDC.
Constituent elements of the electrical network.
Tunneling resistance (Ω) as function of thickness of insulating resin (d) between CNTs and different values of the height of barrier (λ).
Summary of the simulation values.
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