Can the self-propulsion of anisotropic microswimmers be described by using forces and torques?

Abstract

The self-propulsion of artificial and biological microswimmers (i.e., active colloidal particles) has often been modelled by using a force and a torque entering into the overdamped equations for the Brownian motion of passive particles. This seemingly contradicts the fact that a swimmer is force-free and torque-free, i.e., that the net force and torque on the particle vanish. Using different models for mechanical and diffusiophoretic self-propulsion, we demonstrate here that the equations of motion of microswimmers can be mapped onto those of passive particles with the shape-dependent grand resistance matrix and formally external effective forces and torques. This is consistent with experimental findings on the circular motion of artificial asymmetric microswimmers driven by self-diffusiophoresis. The concept of effective self-propulsion forces and torques significantly facilitates the understanding of the swimming paths, e.g., for a microswimmer under gravity. However, this concept has its limitations when the self-propulsion mechanism of a swimmer is disturbed either by another particle in its close vicinity or by interactions with obstacles, such as a wall.

arXiv comment19 pages, 2 figures

References in corpus (56)

• The hydrodynamics of swimming microorganisms
• Self-motile colloidal particles: from directed propulsion to random walk
• Dynamical clustering and phase separation in suspensions of self-propelled colloidal particles
• Meso-scale turbulence in living fluids
• Statistical Mechanics of Interacting Run-and-Tumble Bacteria
• Dynamic clustering in active colloidal suspensions with chemical signaling
• Microswimmers in Patterned Environments
• A Simplest Swimmer at Low Reynolds Number: Three Linked Spheres
• Sedimentation of active colloidal suspensions
• When are active Brownian particles and run-and-tumble particles equivalent? Consequences for motility-induced phase separation
• Diffusive transport without detailed balance in motile bacteria: Does microbiology need statistical physics?
• Circular motion of asymmetric self-propelling particles
• Non-equilibrium clustering of self-propelled rods
• Active Brownian Motion Tunable by Light
• Phase behaviour of active Brownian particles: The role of dimensionality
• Ciliary contact interactions dominate surface scattering of swimming eukaryotes
• Brownian motion of a self-propelled particle
• Phase separation and rotor self-assembly in active particle suspensions
• Dynamics of a Brownian circle swimmer
• Gravitaxis of asymmetric self-propelled colloidal particles
• Crystallization in a dense suspension of self-propelled particles
• Hydrodynamic capture of microswimmers into sphere-bound orbits
• Freezing and phase separation of self-propelled disks
• Giant amplification of interfacially driven transport by hydrodynamic slip: diffusio-osmosis and beyond
• Aggregation of self-propelled colloidal rods near confining walls
• Multi-Particle Collision Dynamics -- a Particle-Based Mesoscale Simulation Approach to the Hydrodynamics of Complex Fluids
• Spontaneous Segregation of Self-Propelled Particles with Different Motilities
• How to capture active particles
• Sorting of Chiral Microswimmers
• Generic theory of colloidal transport
• Emergent states in dense systems of active rods: from swarming to turbulence
• Hydrodynamic suppression of phase separation in active suspensions
• Anomalous Thermomechanical Properties of a Self-propelled Colloidal Fluid
• Spontaneous aggregation and global polar ordering in squirmer suspensions
• Brownian motion and the hydrodynamic friction tensor for colloidal particles of complex shape
• Brownian dynamics of a self-propelled particle in shear flow
• The self-propelled Brownian spinning top: dynamics of a biaxial swimmer at low Reynolds numbers
• Stochastic thermodynamics of active Brownian particles
• Capturing self-propelled particles in a moving microwedge
• Locomotion in complex fluids: Integral theorems
• Motility-sorting of self-propelled particles in micro-channels
• Active Brownian particles with velocity-alignment and active fluctuations
• The collective dynamics of self-propelled particles
• Active Matter Ratchets with an External Drift
• A Lattice-Boltzmann model for suspensions of self-propelling colloidal particles
• Using self-driven microswimmers for particle separation
• Three-Sphere Low Reynolds Number Swimmer with a Cargo Container
• Non-equilibrium hydrodynamics of a rotating filament
• Brownian dynamics of a microswimmer
• Swimming path statistics of an active Brownian particle with time-dependent self-propulsion
• Directed Transport of Confined Brownian Particles with Torque
• Reciprocal locomotion of dense swimmers in Stokes flow
• Reply to Comment on "Circular Motion of Asymmetric Self-Propelling Particles"
• Effective run-and-tumble dynamics of bacteria baths
• Equation of motion for density distribution of many circling particles with an overdamped circle center
• Complete analytic solution to Brownian unicycle dynamics

Cited by in corpus (40)

• Active Particles in Complex and Crowded Environments
• Computational models for active matter
• The physics of active polymers and filaments
• Conformational properties of active semiflexible polymers
• Curling Liquid Crystal Microswimmers: a cascade of spontaneous symmetry breaking
• Stochastic thermodynamics for active matter
• How does a flexible chain of active particles swell?
• Memory-induced transition from a persistent random walk to circular motion for achiral microswimmers
• Viscotaxis: microswimmer navigation in viscosity gradients
• Dynamical Density Functional Theory For Microswimmers
• Nonequilibrium dynamics of mixtures of active and passive colloidal particles
• Chemotaxis of artificial microswimmers in active density waves
• Time-dependent inertia of self-propelled particles: the Langevin rocket
• Helical paths, gravitaxis, and separation phenomena for mass-anisotropic self-propelling colloids: experiment versus theory
• Brownian motion of a circle swimmer in a harmonic trap
• State diagram of a three-sphere microswimmer in a channel
• Active dipole clusters: from helical motion to fission
• Dynamical density functional theory for circle swimmers
• Membrane penetration and trapping of an active particle
• Multi-species dynamical density functional theory for microswimmers: derivation, orientational ordering, trapping potentials, and shear cells
• Getting drowned in a swirl: deformable bead-spring model microswimmers in external flow fields
• Shape matters: A Brownian microswimmer in a channel
• Particle-scale statistical theory for hydrodynamically induced polar ordering in microswimmer suspensions
• Thermal Transport Dynamics in Active Heat Transfer Fluids (AHTF)
• Boids in a Loop: Self-Propelled particles within a Flexible Boundary
• Diffusiophoretic design of self-spinning microgears from colloidal microswimmers
• Efficient shapes for microswimming: from three-body swimmers to helical flagella
• Orientation-dependent propulsion of cone-shaped nano- and microparticles by a traveling ultrasound wave
• Mechanisms of carrier transport induced by a microswimmer bath
• Acoustically propelled nano- and microcones: fast forward and backward motion
• Rectification of Twitching bacteria through narrow channels: A numerical simulations study
• Theory of active particle penetration through a planar elastic membrane
• Cargo Towing by Artificial Swimmers
• Mesoscopic simulations of anisotropic chemically-powered nanomotors
• Designing circle Swimmers: Principles and strategies
• Load response of shape-changing microswimmers scales with their energy efficiency
• Effect of anisotropy on the formation of active particle films
• Dependence of the acoustic propulsion of nano- and microcones on their orientation and aspect ratio
• Nonequilibrium dynamical structure of a dilute suspension of active particles in a viscoelastic fluid
• Inertial dynamics of an active Brownian particle