Controlling Colloidal Flow through a Microfluidic Y-junction

TL;DR

This study demonstrates how tuning particle interactions and confinement in a microfluidic Y-junction can control flow behavior, prevent clogging, and steer particle distribution using experiments and simulations.

Contribution

It introduces a method to control colloidal flow and prevent clogging by adjusting pair interactions and confinement in a Y-junction, supported by combined experimental and simulation analysis.

Findings

Repulsive interactions prevent clogging.

Attractive particles favor the same gate flow.

Flow steering is achieved by tuning interactions.

Abstract

Microscopic particles flowing through narrow channels may accumulate near bifurcation points provoking flow reduction, clogging and ultimately chip breakage. Here we show that the full flow behavior of colloidal particles through a microfluidic Y-junction (i.e. a three way intersection) can be controlled by tuning the pair interactions and the degree of confinement. By combining experiments with numerical simulations, we investigate the dynamic states emerging when magnetizable colloids flow through a symmetric Y-junction such that a single particle can pass through both gates with the same probability. We show that clogging can be avoided by repulsive interactions and branching into the two channels can be steered as well by interactions: attractive particles are flowing through the same gate, while repulsive colloids alternate between the two gates. Even details of the particle assembly such as buckling at the exit gate are tunable by interactions and the channel geometry.