Chiral active matter

Abstract

Chiral active matter comprises particles which can self-propel and self-rotate. Examples range from sperm cells and bacteria near walls to asymmetric colloids and pea-shaped Quincke rollers. In this perspective article we focus on recent developments in chiral active matter. After briefly discussing chiral active motion at a single particle level, we discuss collective phenomena ranging from vortex arrays and patterns made of rotating micro-flocks to states featuring unusual rheological properties.

Collective behavior of passive and active circle swimming particle mixtures

“…24,25 Recent years have also seen many developments in the field of rotating active particles. [26][27][28][29][30][31][32][33] Active rotation is brought about by not allowing the direction of self-propulsion and orientation of the particle to coincide. This is done by introducing a shape asymmetry 29,31 or by using external magnetic and optical fields.…”

The role of disorder in the motion of chiral active particles in the presence of obstacles

“…2 Some active particles, with chiral shapes or with chiral surface properties move in chiral trajectories, typically along circles (2D) or helices (3D). 3 For example, due to hydrodynamic interactions, several micro-swimmers trace circular trajectories when swimming near a substrate. [4][5][6] Significant progress has been made in capturing the behavior of chiral active particles in homogeneous environments.…”

Chiral and nematic phases of flexible active filaments

“…In particular, chiral active matter has recently attracted attention, where the constituents are either asymmetric in shape or perform a circular self-propelled motion. This includes curved cytoskeletal filaments, asymmetric synthetic swimmers or cell types displaying chiral motions on 2D substrates [17][18][19] .…”