Interactions in Active Colloids
arXiv:2110.15249 · doi:10.1088/1361-648X/ac3a86
Abstract
The past two decades have seen a remarkable progress in the development of synthetic colloidal agents which are capable of creating directed motion in an unbiased environment at the microscale. These self-propelling particles are often praised for their enormous potential to self-organize into dynamic nonequilibrium structures such as living clusters, synchronized super-rotor structures or self-propelling molecules featuring a complexity which is rarely found outside of the living world. However, the precise mechanisms underlying the formation and dynamics of many of these structures are still barely understood, which is likely to hinge on the gaps in our understanding of how active colloids interact. In particular, besides showing comparatively short-ranged interactions which are well known from passive colloids (Van der Waals, electrostatic etc.), active colloids show novel hydrodynamic interactions as well as phoretic and substrate-mediated "osmotic" cross-interactions which hinge on the action of the phoretic field gradients which are induced by the colloids on other colloids in the system. The present article discusses the complexity and the intriguing properties of these interactions which in general are long-ranged, non-instantaneous, non-pairwise and non-reciprocal and which may serve as key ingredients for the design of future nonequilibrium colloidal materials. Besides providing a brief overview on the state of the art of our understanding of these interactions a key aim of this review is to emphasize open key questions and corresponding open challenges.
References in corpus (39)
- The hydrodynamics of swimming microorganisms
- Physics of Microswimmers - Single Particle Motion and Collective Behavior
- Fluid dynamics and noise in bacterial cell-cell and cell-surface scattering
- Designing phoretic micro- and nano-swimmers
- Hydrodynamics of self-propulsion near a boundary: predictions and accuracy of far-field approximations
- Phototaxis of synthetic microswimmers in optical landscapes
- Dynamic clustering and chemotactic collapse of self-phoretic active particles
- Phoretic self-propulsion at finite Péclet numbers
- Active phase separation in mixtures of chemically interacting particles
- Artificial Rheotaxis
- Run-and-tumble particles with hydrodynamics: sedimentation, trapping and upstream swimming
- Spontaneous aggregation and global polar ordering in squirmer suspensions
- Self-assembly of Active Colloidal Molecules with Dynamic Function
- Autophoretic locomotion from geometric asymmetry
- Tuning the motility and directionality of self-propelled colloids
- Morphology of clusters of attractive dry and wet self-propelled spherical particle suspensions
- Applicability of Effective Pair Potentials for Active Brownian Particles
- Collective Chemotactic Dynamics in the Presence of Self-Generated Fluid Flows
- Microfluidic Pumping by Micromolar Salt Concentrations
- Universal hydrodynamic mechanisms for crystallization in active colloidal suspensions
- Hydrodynamic interactions in dense active suspensions: from polar order to dynamical clusters
- Collective Dynamics of Dividing Chemotactic Cells
- Multicellular self-organization of P. aeruginosa due to interactions with secreted trails
- Phoretic and hydrodynamic interactions of weakly-confined autophoretic particles
- Chemotactic and hydrodynamic effects on collective dynamics of self-diffusiophoretic Janus motors
- Hydrodynamic Mobility Reversal of Squirmers near Flat and Curved Surfaces
- Collective Sedimentation of Squirmers under Gravity
- Kinetic and hydrodynamic models of chemotactic aggregation
- Collective Dynamics in a Monolayer of Squirmers Confined to a Boundary by Gravity
- A Lattice Boltzmann Model for Squirmers
- Rheotaxis of Active Droplets
- Inverse Solidification Induced by Active Janus Particles
- Modeling chemo-hydrodynamic interactions of phoretic particles: a unified framework
- Hydrochemical interactions of phoretic particles: a regularized multipole framework
- Chemically active colloids near osmotic-responsive walls with surface-chemistry gradients
- Stability of arrays of bottom-heavy spherical squirmers
- Diffusiophoretic design of self-spinning microgears from colloidal microswimmers
- Self-propulsion in 2D Confinement: Phoretic and Hydrodynamic Interactions
- Mixing and unmixing induced by active camphor particles