Giant adsorption of microswimmers: duality of shape asymmetry and wall curvature

TL;DR

This study investigates how the shape asymmetry of microswimmers influences their ability to adhere to walls, revealing a duality with wall curvature and implications for designing microswimmers with controlled adhesion.

Contribution

It introduces a duality relation between shape asymmetry and wall curvature affecting microswimmer adsorption, supported by a simple dumbbell model and analysis.

Findings

Long wall retention times for shape-polar microswimmers due to propulsion force orientation.

A duality relation between shape asymmetry and wall curvature is established and verified.

Active system pressure is highly sensitive to particle-wall interaction details.

Abstract

The effect of shape asymmetry of microswimmers on their adsorption capacity at confining channel walls is studied by a simple dumbbell model. For a shape polarity of a forward-swimming cone, like the stroke-averaged shape of a sperm, extremely long wall retention times are found, caused by a non-vanishing component of the propulsion force pointing steadily into the wall, which grows exponentially with the self-propulsion velocity and the shape asymmetry. A direct duality relation between shape asymmetry and wall curvature is proposed and verified. Our results are relevant for the design microswimmer with controlled wall-adhesion properties. In addition, we confirm that pressure in active systems is strongly sensitive to the details of the particle-wall interactions.