  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.
