Confinement effects on the random sequential adsorption packings of elongated particles in a slit

TL;DR

This study investigates how confinement and particle elongation influence the packing density, order, and connectivity of elongated particles in a slit, revealing complex dependencies driven by geometry and orientation.

Contribution

It provides a detailed simulation analysis of how aspect ratio and slit width affect packing and percolation in two-dimensional elongated particle systems.

Findings

Packing density varies non-trivially with aspect ratio and slit width.

Particle orientation and confinement significantly influence percolation connectivity.

Geometrical factors explain the observed dependencies in packing and connectivity.

Abstract

The behavior of a system of two-dimensional elongated particles (discorectangles) packed into a slit between two parallel walls was analyzed using a simulation approach. The packings were produced using the random sequential adsorption model with continuous positional and orientational degrees of freedom. The aspect ratio (length-to-width ratio, $\varepsilon=l/d$) of the particles was varied within the range $\varepsilon \in [1;32]$ while the distance between the walls was varied within the range $h/d\in [1;80]$. The properties of the deposits when in the jammed state (the coverage, the order parameter, and the long-range (percolation) connectivity between particles) were studied numerically. The values of $\varepsilon$ and $h$ significantly affected the structure of the packings and the percolation connectivity. In particular, the observed nontrivial dependencies of the jamming coverage $\varphi(\varepsilon)$ or $\varphi(h)$ were explained by the interplay of the different geometrical factors related to confinement, particle orientation degrees of freedom and excluded volume effects.