Rotation and propulsion in 3d active chiral droplets

Abstract

Chirality is a recurrent theme in the study of biological systems, in which active processes are driven by the internal conversion of chemical energy into work. Bacterial flagella, acto-myosin filaments and microtubule bundles are active systems which are also intrinsically chiral. Despite some exploratory attempt to capture the relations between chirality and motility, no intrinsically chiral system has ever been analyzed so far. To address this gap in knowledge, here we study the effects of internal active forces and torques on a three-dimensional droplet of cholesteric liquid crystal (CLC) embedded in an isotropic liquid. We consider tangential anchoring of the liquid crystal director at the droplet surface. Contrary to what happens in nematics, where moderate extensile activity leads to droplet rotation, cholesteric active droplets exhibit a lot more complex and variegated behaviors. We find that extensile force dipole activity stabilises complex defect configurations whose orbiting dynamics couples to thermodynamic chirality to propel screw-like droplet motion. Instead, dipolar torque activity may either tighten or unwind the cholesteric helix, and if tuned can power rotations with an oscillatory angular velocity of zero mean.

References in corpus (20)

• The Mechanics and Statistics of Active Matter
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• Rheology of Active-Particle Suspensions
• Living Liquid Crystals
• Full phase diagram of active Brownian disks: from melting to motility-induced phase separation
• Lattice Boltzmann Simulations of Liquid Crystal Hydrodynamics
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• Shearing active gels close to the isotropic-nematic transition
• Active turbulence in active nematics
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• Topology of three-dimensional active nematic turbulence confined to droplets
• Hydrodynamic instabilities in active cholesteric liquid crystals
• Spontaneous rotation can stabilise ordered chiral active fluids
• Lamellar ordering, droplet formation and phase inversion in exotic active emulsions
• Morphology and flow patterns in highly asymmetric active emulsions
• Chaotic and periodical dynamics of active chiral droplets

Cited by in corpus (31)

• Topological active matter
• Active Turbulence
• Theory of defect-mediated morphogenesis
• Discrete Boltzmann multi-scale modeling of non-equilibrium multiphase flows
• Lattice Boltzmann Methods and Active Fluids
• Design of nematic liquid crystals to control microscale dynamics
• Dynamics of a chiral swimmer sedimenting on a flat plate
• Morphology of active deformable 3D droplets
• Chiral active matter in external potentials
• Hydrodynamics of chiral squirmers
• Cascade or not cascade? Energy transfer and elastic effects in active nematics
• The crucial role of adhesion in the transmigration of active droplets through interstitial orifices
• Cholesteric shells: two-dimensional blue fog and finite quasicrystals
• Impact of chirality on active Brownian particle: Exact moments in two and three dimensions
• Defect Line Coarsening and Refinement in Active Nematics
• Spontaneous rotation of active droplets in two and three dimensions
• Soft channel formation and symmetry breaking in exotic active emulsions
• Defect Loops in Three-Dimensional Active Nematics as Active Multipoles
• Tuneable defect-curvature coupling and topological transitions in active shells
• Hydrodynamic Enhancement of $p$-atic Defect Dynamics
• Chirality, anisotropic viscosity and elastic anisotropy in three-dimensional active nematic turbulence
• Activity induced isotropic-polar transition in active liquid crystals
• Rheology of active emulsions with negative effective viscosity
• Topological Phases and Curvature-Driven Pattern Formation in Cholesteric Shells
• Spontaneous rotation and propulsion of suspended capsules in active nematics
• Lattice Boltzmann simulations of self-propelling chiral active droplets
• Lattice Boltzmann modeling of cholesteric liquid crystal droplets under an oscillatory electric field
• Simulations of Three-dimensional Nematic Guidance of Microswimmers
• Active screws: Emergent active chiral nematics of spinning self-propelled rods
• Motility and self propulsion of active droplets
• Viscotaxis of chiral microswimmer in viscosity gradients