Diffusive properties of colloidal charged particles in a quasi-one-dimensional confinement

Levi Rodrigues Leite,João Cláudio Nunes Carvalho,Leandro Jader Pitombeira Xavier,Jorge Luiz Bezerra De Araújo,Diego De Lucena Camarão,Vagner Henrique Loiola Bessa

doi:10.33448/rsd-v10i12.20595

Abstract

Diffusive properties of colloidal crystals in a quasi-one-dimensional channel are studied using numerical simulations. In order to study the influence of the attractive interaction between particles, it was introduced as an artificial dimensionless parameter β in the attractive term of the interaction potential. Changing the value of β, we can tune the effect of attraction between particles. We show that charged particles can change their mobility and the diffusion exponent of a one-chain like system. Variation on exponent diffusion can be induced by tuning the attractive part of interaction potential, making possible the existence of diffusive regimes between single-file diffusion (SFD) and normal diffusion, without changing confinement strength. System stoichiometry was changed, imposing particles in different arrangements in small clusters, which varies the diffusive behaviour. If stoichiometry is different from 1:1, it is possible to have particles with equal charges but with different mobilities. Another important observation is that mean-square displacement (MSD) for different charges is different for different values.

Highlights

Diffusion can be defined as the movement of particles under influence of a concentration gradient
Mean-Square Displacement we present our results about particles' diffusive regimes
Even with β = 1.0, attractive interaction induces particles to form trimmer-like structures which behave as a screened single particle

Summary

Introduction

Diffusion can be defined as the movement of particles under influence of a concentration gradient. A particular case of confined geometry happens when particles are restricted to move along a line in a channel so narrow that particles cannot cross each other, so the sequence of particle labels does not change in time This impossibility of particles crossing induces a collective motion of particles in the same direction. In this situation, anomalous diffusion can be observed (Harris, 1965) such that the mean-square displacement, This result is in contrast with normal diffusion, where the mean-square displacement grows proportional to time. Anomalous diffusion can be observed (Harris, 1965) such that the mean-square displacement, This result is in contrast with normal diffusion, where the mean-square displacement grows proportional to time This phenomenon is called Single-file diffusion (SFD), and it has been studied in different contexts in monodisperse systems. In SFD, particles are correlated because particle movement induces other particles to move together

Methods

Results

Conclusion