A theoretical analysis of the resolution due to diffusion and size-dispersion of particles in deterministic lateral displacement devices

TL;DR

This paper develops a theoretical model for particle separation in deterministic lateral displacement devices, accounting for diffusion and size dispersion, and explains deviations observed in experiments for small particles.

Contribution

It introduces a comprehensive model that includes diffusion and size dispersion effects, providing critical diameters for particle separation in DLD devices.

Findings

Identifies the upper critical diameter where diffusion dominates

Determines the lower critical diameter for convection-driven displacement

Explains experimental deviations for small particles

Abstract

We present a model including diffusion and particle-size dispersion for separation of particles in deterministic lateral displacement devices also known as bumper arrays. We determine the upper critical diameter for diffusion-dominated motion and the lower critical diameter for pure convection-induced displacement. Our model explains the systematic deviation, observed for small particles in several experiments, from the critical diameter for separation given by simple laminar flow considerations.