How to capture active particles

TL;DR

This paper introduces an optimized chevron-shaped trap design for capturing self-propelled colloidal rods, demonstrating how trap geometry influences trapping efficiency through simulation-based phase diagrams.

Contribution

It proposes a novel static chevron-shaped trap and analyzes its efficiency in capturing active particles, providing a phase diagram for optimal trapping conditions.

Findings

Optimal trapping achieved with specific chevron angles.

Three trapping states identified: partial, complete, none.

Trap efficiency can be tuned by adjusting the opening angle.

Abstract

For many applications, it is important to catch collections of autonomously navigating microbes and man-made microswimmers in a controlled way. Here we propose an efficient trap to collectively capture self-propelled colloidal rods. By means of computer simulation in two dimensions, we show that a static chevron-shaped wall represents an optimal boundary for a trapping device. Its catching efficiency can be tuned by varying the opening angle of the trap. For increasing angles, there is a sequence of three emergent states corresponding to partial, complete, and no trapping. A trapping `phase diagram' maps out the trap conditions under which the capture of self-propelled particles at a given density is rendered optimal.