Single-file transport of binary hard-sphere mixtures through periodic potentials

Abstract

Single-file transport occurs in various scientific fields, including diffusion through nanopores, nanofluidic devices, and cellular processes. We here investigate the impact of polydispersity on particle currents for single-file Brownian motion of hard spheres, when they are driven through periodic potentials by a constant drag force. Through theoretical analysis and extensive Brownian dynamics simulations, we unveil the behavior of particle currents for random binary mixtures. The particle currents show a recurring pattern in dependence of the hard-sphere diameters and mixing ratio. We explain this recurrent behavior by showing that a basic unit cell exists in the space of the two hard-sphere diameters. Once the behavior of an observable inside the unit cell is determined, it can be inferred for any diameter. The overall variation of particle currents with the mixing ratio and hard-sphere diameters is reflected by their variation in the limit where the system is fully covered by hard spheres. In this limit, the currents can be predicted analytically. Our analysis explains the occurrence of pronounced maxima and minima of the currents by changes of an effective potential barrier for the center-of-mass motion.

10 pages, 7 figures

References in corpus (5)

• Power functional theory for many-body dynamics
• Modeling diffusion in colloidal suspensions by dynamical density functional theory using fundamental measure theory of hard spheres
• Solitons in overdamped Brownian dynamics
• Brownian dynamics simulations of hard rods in external fields and with contact interactions
• Brownian Dynamics Simulation of Polydisperse Hard Spheres