Shape, connectedness percolation and electrical conductivity of clusters in suspensions of hard platelets

Abstract

Using Monte Carlo simulations, we investigate how geometric percolation and electrical conductivity in suspensions of hard conducting platelets are affected by the addition of platelets and their degree of spontaneous alignment. For aspect ratios $10,25$ and $50$, we consistently observe a monotonically decreasing percolation threshold as a function of volume fraction. In the nematic phase, the distribution of particles inside the percolating clusters becomes less spherically symmetric and the aspect ratio of the clusters increases. However, the clusters are also anisotropically shaped in the isotropic phase, although their aspect ratio remains constant as a function of volume fraction. Mapping the percolating clusters of platelets to linear resistor networks, and assigning unit conductance to all connections, we find a constant conductivity both across the isotropic-nematic transition and in the respective stable phases. This behaviour is consistent with the other observed topological properties of the networks. On the contrary, using an anisotropic conductance model, the network conductivity decreases with increasing volume fraction in the isotropic, and further diminishes at the onset of the nematic. Hence, our observations consistently suggest that unlike for rod-like fillers, the network structures that arise from platelet suspensions are neither very sensitive to the particle aspect ratio nor to alignment, thus rendering platelets less versatile fillers for dispersion in conductive composites.

References in corpus (13)

• Solution of the tunneling-percolation problem in the nanocomposite regime
• Percolation in suspensions of hard nanoparticles: From spheres to needles
• Percolative properties of hard oblate ellipsoids of revolution with a soft shell
• Connectivity percolation in suspensions of hard platelets
• Hopping conductivity of a suspension of nanowires in an insulator
• Continuum Percolation of Polydisperse Rods in Quadrupole Fields: Theory and Simulations
• Anisotropy in electrical conductivity and transparency of films of aligned conducting rods
• Connectivity, Not Density, Dictates Percolation in Nematic Liquid Crystals of Slender Nanoparticles
• Impact of tunneling anisotropy on the conductivity of nanorod dispersions
• Depletion interaction effects on the tunneling conductivity of nanorod suspensions
• Tunneling conductivity in anisotropic nanofibre composites: a percolation-based model
• Unusual geometric percolation of hard nanorods in the uniaxial nematic liquid crystalline phase
• Simulation study of the electrical tunneling network conductivity of suspensions of hard spherocylinders

Cited by in corpus (1)

• Re-entrant percolation in active Brownian hard disks