Spontaneous chiralization of polar active colloids

TL;DR

This paper reveals a universal self-phoretic mechanism causing polar active colloids to spontaneously develop chiral motion through a symmetry-breaking instability, resulting in active rotation and circular trajectories.

Contribution

It introduces a novel, generic mechanism explaining how polar active colloids can spontaneously become chiral via a symmetry-breaking instability.

Findings

Active particles exhibit spontaneous chiralization with circular trajectories.

The transition is driven by solute advection and surface interactions.

The instability occurs through a supercritical pitchfork bifurcation.

Abstract

Polar active particles constitute a wide class of synthetic colloids that are able to propel along a preferential direction, given by their polar axis. Here, we demonstrate a generic self-phoretic mechanism that leads to their spontaneous chiralization through a symmetry breaking instability. We find that the transition of an active particle from a polar to a chiral symmetry is characterized by the emergence of active rotation and of circular trajectories. We show that the instability is driven by the advection of a solute that interacts differently with the two portions of the particle surface and it occurs through a supercritical pitchfork bifurcation.