Transport properties of nonhomogeneous segregated composites

Nigro, Biagio; Ambrosetti, Gianluca; Grimaldi, Claudio; Maeder, Thomas; Ryser, Peter

doi:10.1103/physrevb.83.064203

Cited by 19 publications

(27 citation statements)

References 50 publications

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“…To calculate δ c , we coat each conducting sphere with a concentric penetrable shell of thickness δ 0 /2, for each configuration of the system at a given volume fraction φ and time t; we consider two spheres as connected if their penetrable shells overlap (i.e., if δ ij ≤ δ 0 ). Using a clustering algorithm [32], we compute the minimum value δ of δ 0 such that a cluster of connected particles connects two opposite faces of the simulation box. We repeat this procedure along all three axes of the Gelation considerably lowers the values of δ for which P (δ) increases from 0 to 1, as shown in Fig.…”

Section: Critical Path Approximationmentioning

confidence: 99%

Enhanced tunneling conductivity induced by gelation of attractive colloids

et al. 2013

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We show that the formation of a gel by conducting colloidal particles leads to a dramatic enhancement in bulk conductivity, due to interparticle electron tunneling, combining predictions from molecular-dynamics simulations with structural measurements in an experimental colloid system. Our results show how colloidal gelation can be used as a general route to huge enhancements of conductivity, and suggest a feasible way for developing cheap materials with novel properties and low metal content.

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Section: Critical Path Approximationmentioning

confidence: 99%

Enhanced tunneling conductivity induced by gelation of attractive colloids

et al. 2013

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“…As mentioned above, theories and simulations on systems of polydispersed rods predict that the tunnelling conductivity depends on the length distribution of the rods only through L w . This is readily seen by adopting the critical distance approximation for σ 8,12,[30][31][32]…”

Section: Resultsmentioning

confidence: 99%

Role of the particle size polydispersity in the electrical conductivity of carbon nanotube-epoxy composites

Molaei

Grimaldi

Forró

et al. 2017

Sci Rep

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Carbon nanotubes (CTNs) with large aspect-ratios are extensively used to establish electrical connectedness in polymer melts at very low CNT loadings. However, the CNT size polydispersity and the quality of the dispersion are still not fully understood factors that can substantially alter the desired characteristics of CNT nanocomposites. Here we demonstrate that the electrical conductivity of polydisperse CNT-epoxy composites with purposely-tailored distributions of the nanotube length L is a quasiuniversal function of the first moment of L. This finding challenges the current understanding that the conductivity depends upon higher moments of the CNT length. We explain the observed quasiuniversality by a combined effect between the particle size polydispersity and clustering. This mechanism can be exploited to achieve controlled tuning of the electrical transport in general CNT nanocomposites.

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“…We note that for large values of D 1 /ξ, which is the regime of practical interest for our purposes [17] (see also Sec. I), W (r) is well approximated by θ(r * −r), where θ(x) is 1 for x ≥ 0 and 0 otherwise.…”

Section: B Ema Analytical Formulamentioning

confidence: 97%

Tunneling and percolation transport regimes in segregated composites

2012

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We consider the problem of electron transport in segregated conductor-insulator composites in which the conducting particles are connected to all others via tunneling conductances thus forming a global tunneling connected resistor network. Segregation is induced by the presence of large insulating particles which forbid the much smaller conducting fillers to occupy uniformly the three dimensional volume of the composite. By considering both colloidal-like and granular-like dispersions of the conducting phase, modeled respectively by dispersions in the continuum and in the lattice, we evaluate by Monte Carlo simulations the effect of segregation on the composite conductivity σ, and show that an effective medium theory applied to the tunneling network reproduces accurately the Monte Carlo results. The theory clarifies that the main effect of segregation in the continuum is that of reducing the mean inter-particle distances, leading to a strong enhancement of the conductivity. In the lattice segregation case the conductivity enhancement is instead given by the lowering of the percolation thresholds for first and beyond-first nearest neighbors. Our results generalize to segregated composites the tunneling-based description of both the percolation and hopping regimes introduced previously for homogeneous disordered systems.

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Transport properties of nonhomogeneous segregated composites

Cited by 19 publications

References 50 publications

Enhanced tunneling conductivity induced by gelation of attractive colloids

Enhanced tunneling conductivity induced by gelation of attractive colloids

Role of the particle size polydispersity in the electrical conductivity of carbon nanotube-epoxy composites

Tunneling and percolation transport regimes in segregated composites

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