Percolative properties of hard oblate ellipsoids of revolution with a soft shell

Abstract

We present an in-depth analysis of the geometrical percolation behavior in the continuum of random assemblies of hard oblate ellipsoids of revolution. Simulations were carried out by considering a broad range of aspect ratios, from spheres up to aspect-ratio-100 platelike objects, and with various limiting two-particle interaction distances, from 0.05 times the major axis up to 4.0 times the major axis. We confirm the widely reported trend of a consistent lowering of the hard particle critical volume fraction with increase of the aspect ratio. Moreover, by assimilating the limiting interaction distance to a shell of constant thickness surrounding the ellipsoids, we propose a simple relation based on the total excluded volume of these objects which allows us to estimate the critical concentration from a quantity that is quasi-invariant over a large spectrum of limiting interaction distances. Excluded volume and volume quantities are derived explicitly.