Density Reduction and Diffusion in Driven 2d-Colloidal Systems Through Microchannels

TL;DR

This study investigates how particles driven through narrow channels self-organize into layers, reduce their density, and exhibit fluctuating flow behaviors, combining experimental and simulation approaches to understand these dynamics.

Contribution

It introduces a combined experimental and simulation analysis of particle behavior in microchannels, revealing self-organized layering, density reduction, and flow fluctuations.

Findings

Particles form layers and density gradients in channels.

Layer reduction occurs when energetically favorable, with fluctuating zones.

Flow velocities and diffusion reflect self-organized order.

Abstract

The behavior of particles driven through a narrow constriction is investigated in experiment and simulation. The system of particles adapts to the confining potentials and the interaction energies by a self-consistent arrangement of the particles. It results in the formation of layers throughout the channel and of a density gradient along the channel. The particles accommodate to the density gradient by reducing the number of layers one by one when it is energetically favorable. The position of the layer reduction zone fluctuates with time while the particles continuously pass this zone. The flow behavior of the particles is studied in detail. The velocities of the particles and their diffusion behavior reflect the influence of the self-organized order of the system.