Active Brownian motion in a narrow channel

TL;DR

This paper reviews recent progress in controlling the movement of artificial microswimmers, especially Janus particles, in narrow corrugated channels, highlighting how chirality influences their transport and diffusivity.

Contribution

It provides a comprehensive review of how propulsion chirality affects microswimmer transport in various channel geometries and introduces new findings on the role of self-propulsion torque.

Findings

Chirality significantly impacts microswimmer current and transport properties.

Asymmetric channel geometries lead to different transport behaviors.

Self-propulsion torque is a key control parameter for microswimmer diffusivity.

Abstract

We review recent advances in rectification control of artificial microswimmers, also known as Janus particles, diffusing along narrow, periodically corrugated channels. The swimmer self-propulsion mechanism is modeled so as to incorporate a nonzero torque (propulsion chirality). We first summarize the effects of chirality on the autonomous current of microswimmers freely diffusing in channels of different geometries. In particular, left-right and upside-down asymmetric channels are shown to exhibit different transport properties. We then report new results on the dependence of the diffusivity of chiral microswimmers on the channel geometry and their own self-propulsion mechanism. The self-propulsion torque turns out to play a key role as a transport control parameter.