Contractile and chiral activities co-determine the helicity of swimming droplet trajectories

Abstract

Active fluids are a class of non-equilibrium systems where energy is injected into the system continuously by the constituent particles themselves. Many examples, such as bacterial suspensions and actomyosin networks, are intrinsically chiral at a local scale, so that their activity involves torque dipoles alongside the force dipoles usually considered. Although many aspects of active fluids have been studied, the effects of chirality on them are much less known. Here we study by computer simulation the dynamics of an unstructured droplet of chiral active fluid in three dimensions. Our model only considers the simplest possible combination of chiral and achiral active stresses, yet this leads to an unprecedented range of complex motilities, including oscillatory swimming, helical swimming, and run-and-tumble motion. Strikingly, while the chirality of helical swimming is the same as the microscopic chirality of torque dipoles in one regime, the two are opposite in another. Some of the features of these motility modes resemble those of some single-celled protozoa, suggesting that underlying mechanisms may be shared by some biological systems and synthetic active droplets.

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Cited by in corpus (27)

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• Dynamics of a chiral swimmer sedimenting on a flat plate
• Edge Current and Pairing Order Transition in Chiral Bacterial Vortex
• Morphology of active deformable 3D droplets
• Active cholesterics: odder than odd elasticity
• Spontaneous rotation can stabilise ordered chiral active fluids
• Hydrodynamics of chiral squirmers
• Topological states in chiral active matter: dynamic blue phases and active half-skyrmions
• Chiral active hexatics: Giant number fluctuations, waves and destruction of order
• Paramagnetic filaments in a fast precessing field: Planar versus helical conformations
• Active fluids at circular boundaries: Swim pressure and anomalous droplet ripening
• Transport of the moving barrier driven by chiral active particles
• Chirality-induced helical self-propulsion of cholesteric liquid crystal droplets
• Lattice Boltzmann study of chemically-driven self-propelled droplets
• Fluctuations, renormalizations, and a convective instability in driven wet active matter
• Diffusion of active particles with angular velocity reversal
• Topological Phases and Curvature-Driven Pattern Formation in Cholesteric Shells
• Activity pulses induce spontaneous flow reversals in viscoelastic environments
• Shapes and dynamic regimes of a polar active fluid droplet under confinement
• Motility and self propulsion of active droplets
• Active screws: Emergent active chiral nematics of spinning self-propelled rods
• Screw Symmetry, Chiral Hydrodynamics and Odd Instability in Active Cholesterics
• Viscotaxis of chiral microswimmer in viscosity gradients