Common Packing Patterns for Jammed Particles of Different Power Size Distributions

TL;DR

This study investigates the packing patterns of highly polydisperse particles with power-law size distributions in 2D, revealing common contact number distributions and a higher jamming point, leading to a new classification scheme.

Contribution

It introduces a scale-invariant model for polydisperse particles and identifies universal packing properties across different size exponents.

Findings

Common contact number distribution for a<3

Higher jamming point in 2<a<3 than monodisperse systems

Scale-invariance leads to a new classification scheme

Abstract

We introduce a model for particles that are extremely polydisperse in size compared to monodisperse and bidisperse systems. In two dimensions (2D), size polydispersity inhibits crystallization and increases packing fraction at jamming points. However, no packing pattern common to diverse polydisperse particles has been reported. We focused on polydisperse particles with a power size distribution $r^{-a}$ as a ubiquitous system that can be expected to be scale-invariant. We experimentally and numerically constructed 2D random packing for various polydisperse particles with different size exponents, $a$. Analysis of the packing pattern revealed a common contact number distribution for $a<3$ and a higher jamming point in $2<a<3$ than monodisperse systems. These findings demonstrate that the ambiguity of the characteristic length provides the common properties that leads to a novel classification scheme for polydisperse particles.