Light-induced Non-uniform Surface Polarization Evolution as Active Matter Motion Mechanism

TL;DR

This paper introduces a light-induced polarization mechanism that drives micro-swimmer motion in water, supported by a mathematical model and velocity estimates aligning with experiments.

Contribution

It proposes a novel active matter motion mechanism based on polarization perturbations caused by light, with a mathematical framework and experimental velocity estimates.

Findings

The mechanism explains directed micro-swimmer motion via polarization and surface deformations.

Mathematical solutions show translation and rotation of polarization distributions.

Estimated velocities match experimentally observed values.

Abstract

A new mechanism for micro-swimmer motion in an aquatic environment, which implies light-induced polarization perturbations as a motivation for its motion, is proposed. The mechanism assumes that natural light leads to an enhancement of the non-uniform polarization distribution at the micro-swimmer's surface and also to an enhancement of its surface deformations. The interaction of such non-uniform polarization with free charges of the environment and the mechanical interaction of surface deformations with media flows lead to the directed micro-swimmer motion. The mathematical justification for this mechanism is based on the free energy functional minimization in terms of polarization. The obtained solutions correspond to the translation motion along the micro-swimmer and the rotation of the non-uniform polarization distribution. The estimation of the velocity of micro-swimmer motion, which is based on the hydrodynamics of the active matter, corresponds to the experimentally observed values.