Stochastic and Deterministic Vector Chromatography of Suspended Particles in 1D-Periodic Potentials

TL;DR

This paper develops a comprehensive model of vector chromatography incorporating both deterministic and stochastic transport in 1D periodic energy landscapes, validated by microfluidic experiments demonstrating particle separation based on size and density.

Contribution

It introduces a unified framework for vector chromatography that accounts for energetic and entropic effects, and explores how landscape shape influences deflection angles.

Findings

Model accurately predicts deflection angles in microfluidic experiments.

Experimental validation shows effective separation of particles by size and density.

Landscape shape significantly affects particle deflection behavior.

Abstract

We present a comprehensive description of vector chromatography that includes deterministic and stochastic transport in 1D-periodic free-energy landscapes, with both energetic and entropic contributions, and highlights the parameters governing the deflection angle, i.e. the Peclet number and the partition ratio. We also investigate the dependence of the deflection angle on the shape of the free-energy landscape by varying the width of the linear transitions in an otherwise dichotomous potential. Finally, we present experimental results obtained in a microfluidic system in which gravity drives the suspended particles and, in combination with a bottom surface patterned with shallow rectangular grooves, creates a periodic landscape of (potential) energy barriers. The experiments validate the model and demonstrate that a simple, passive microdevice can lead to vector separation of colloidal particles based on both size and density.