Tunable structure and dynamics of active liquid crystals

Abstract

Active materials are capable of converting free energy into directional motion, giving rise to striking dynamical phenomena. Developing a general understanding of their structure in relation to the underlying non-equilibrium physics would provide a route towards control of their dynamic behavior and pave the way for potential applications. The active system considered here consists of a quasi-two-dimensional sheet of short ($\approx$ 1 $\mu$m) actin filaments driven by myosin-II motors. By adopting a concerted theoretical and experimental strategy, new insights are gained into the non-equilibrium properties of active nematics over a wide range of internal activity levels. In particular, it is shown that topological defect interactions can be led to transition from attractive to repulsive as a function of initial defect separation and relative orientation. Furthermore, by examining the +1/2 defect morphology as a function of activity, it is found that the apparent elastic properties of the system (the ratio of bend-to-splay elastic moduli) are altered considerably by increased activity, leading to an effectively lower bend elasticity. At high levels of activity, the topological defects that decorate the material exhibit a liquid-like structure, and adopt preferred orientations depending on their topological charge. Taken together, these results suggest that it should be possible to tune internal stresses in active nematic systems with the goal of designing out-of-equilibrium structures with engineered dynamic responses.

References in corpus (22)

• Spontaneous motion in hierarchically assembled active matter
• Hydrodynamic fluctuations and instabilities in ordered suspensions of self-propelled particles
• Long-lived Giant Number Fluctuations in a Swarming Granular Nematic
• Topology and Dynamics of Active Nematic Vesicles
• Rheology of Active-Particle Suspensions
• Topological defect launches 3D mound in the active nematic sheet of neural progenitors
• Living Liquid Crystals
• Defect annihilation and proliferation in active nematics
• Orientational order of motile defects in active nematics
• Steady-state hydrodynamic instabilities of active liquid crystals: Hybrid lattice Boltzmann simulations
• Flocking at a distance in active granular matter
• Command of active matter by topological defects and patterns
• Lattice Boltzmann Simulations of Liquid Crystal Hydrodynamics
• Patterning active materials with addressable soft interfaces
• Hydrodynamics of topological defects in nematic liquid crystals
• Modeling planar degenerate wetting and anchoring in nematic liquid crystals
• Correlation lengths in hydrodynamic models of active nematics
• Interplay of Structure, Elasticity and Dynamics in Actin-Based Nematic Materials
• Orientation of topological defects in 2D nematic liquid crystals
• Orientational properties of nematic disclinations
• Probing the shear viscosity of an active nematic
• Transition to zero resistance in a two dimensional electron gas driven with microwaves

Cited by in corpus (63)

• Topological active matter
• Active Turbulence
• Topological structure and dynamics of three dimensional active nematics
• Topological defects promote layer formation in Myxococcus xanthus colonies
• Data-driven quantitative modeling of bacterial active nematics
• Structuring Stress for Active Materials Control
• Machine learning active-nematic hydrodynamics
• Statistical Properties of Autonomous Flows in 2D Active Nematics
• Polar jets of swimming bacteria condensed by a patterned liquid crystal
• Entropy Production Rate is Maximized in Non-Contractile Actomyosin
• Submersed Micropatterned Structures Control Active Nematic Flow, Topology and Concentration
• Hydrodynamics of Active Defects: from order to chaos to defect ordering
• Filopodia rotate and coil by actively generating twist in their actin shaft
• Design of nematic liquid crystals to control microscale dynamics
• Microfluidic control over topological states in channel-confined nematic flows
• Tunable corrugated patterns in an active gel sheet
• Geometry and mechanics of disclination lines in 3D nematic liquid crystals
• Analytical approach to chiral active systems: suppressed phase separation of interacting Brownian circle swimmers
• Active nematic defects and epithelial morphogenesis
• Data-driven discovery of active nematic hydrodynamics
• Active nematics with anisotropic friction: the decisive role of the flow aligning parameter
• Role of friction in multidefect ordering
• Sculpting stable structures in pure liquids
• Multiscale Microtubule Dynamics in Active Nematics
• Topological states in chiral active matter: dynamic blue phases and active half-skyrmions
• The role of fluid flow in the dynamics of active nematic defects
• Molecular-scale substrate anisotropy and crowding drive long-range nematic order of cell monolayers
• Rectified Rotational Dynamics of Mobile Inclusions in Two-Dimensional Active Nematics
• Singularity identification for the characterization of topology, geometry, and motion of nematic disclination lines
• Defect Spirograph: Dynamical Behavior of Defects in Spatially Patterned Active Nematics
• Shear-induced gelation of self-yielding active networks
• Orientational correlations in active and passive nematic defects
• Controlling topological defects and contractile flow in confined nematic cell population
• Fluctuations can induce local nematic order and extensile stress in monolayers of motile cells
• Programming tunable active dynamics in a self-propelled robot
• Active liquid crystals powered by force-sensing DNA-motor clusters
• Binding self-propelled topological defects in active turbulence
• Asymmetric fluctuations and self-folding of active interfaces
• Flow around topological defects in active nematic films
• Motor crosslinking augments elasticity in active nematics
• Defect absorption and emission for $p$-atic liquid crystals on cones
• Catapulting of topological defects through elasticity bands in active nematics
• Many-defect solutions in planar nematics: interactions, spiral textures and boundary conditions
• Frank-Read Mechanism in Nematic Liquid Crystals
• Nonlinear spontaneous flow instability in active nematics
• Traction and Stress Control Formation and Motion of +1/2 Topological Defects in Epithelial Cell Monolayers
• Activity pulses induce spontaneous flow reversals in viscoelastic environments
• Self-organization and shape change by active polarization in nematic droplets
• Cells around the corner
• Front speed and pattern selection of a propagating chemical front in an active fluid
• Nucleation and shape dynamics of model nematic tactoids around adhesive colloids
• Spontaneous assembly of condensate networks during the demixing of structured fluids
• Distinct impacts of polar and nematic self-propulsion on active unjamming
• Quadrupolar active stress induces exotic phases of defect motion in active nematics
• Spontaneous rotation and propulsion of suspended capsules in active nematics
• Elasticity tunes mechanical stress localization around active topological defects
• Nematic liquid crystal flow driven by time-varying active surface anchoring
• Anti-hyperuniform Critical States of Active Topological Defects
• Self-sustained oscillations of active viscoelastic matter
• Turbulence to order transitions in activity patterned active nematics
• Transverse Self-Propulsion Enhances the Aggregation of Active Dumbbells
• Filamentous Active Matter: Band Formation, Bending, Buckling, and Defects
• Dynamical arrest in active nematic turbulence