Clustering-induced self-propulsion of isotropic autophoretic particles

Varma, Akhil; Montenegro‐Johnson, Thomas D.; Michelin, Sébastien

doi:10.1039/c8sm00690c

Cited by 67 publications

(93 citation statements)

References 64 publications

(102 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the following, the general framework is first presented for the chemical problem, generalizing the method proposed in [77] for homogeneous particles to the general case of arbitrary surface activity, in order to determine the successive moments of the surface concentration on each particle as a result of their activity. In a second step, the corresponding method is presented for the hydrodynamic problem using the output of the chemical dynamics as a forcing and constructing the resulting particle velocities.…”

Section: The Methods Of Reflections For Phoretic Problemsmentioning

confidence: 99%

See 1 more Smart Citation

Modeling chemo-hydrodynamic interactions of phoretic particles: A unified framework

Varma

Michelin

2019

Phys. Rev. Fluids

Self Cite

View full text Add to dashboard Cite

Phoretic particles exploit local self-generated physico-chemical gradients to achieve self-propulsion at the micron scale. The collective dynamics of a large number of such particles is currently the focus of intense research efforts, both from a physical perspective to understand the precise mechanisms of the interactions and their respective roles, as well as from an experimental point of view to explain the observations of complex dynamics as well as formation of coherent large-scale structures. However, an exact modelling of such multi-particle problems is difficult and most efforts so far rely on the superposition of far-field approximations for each particle's signature, which are only valid asymptotically in the dilute suspension limit. A systematic and unified analytical framework based on the classical Method of Reflections (MoR) is developed here for both Laplace and Stokes' problems to obtain the higher-order interactions and the resulting velocities of multiple phoretic particles, up to any order of accuracy in the radius-to-distance ratio ε of the particles. Beyond simple pairwise chemical or hydrodynamic interactions, this model allows us to account for the generic chemo-hydrodynamic couplings as well as N -particle interactions (N ≥ 3). The ε 5 -accurate interaction velocities are then explicitly obtained and the resulting implementation of this MoR model is discussed and validated quantitatively against exact solutions of a few canonical problems.

show abstract

Section: The Methods Of Reflections For Phoretic Problemsmentioning

confidence: 99%

“…In this highly-symmetric setting, the chemical and hydrodynamic fields as well as the particles' velocities can be obtained analytically for an arbitrary distance using bispherical coordinates [66,77] (Appendix B). The resulting flow and concentration fields are reported on Figure 5.…”

Section: A Axisymmmetric Relative Translation Of Two Janus Particlesmentioning

confidence: 99%

Modeling chemo-hydrodynamic interactions of phoretic particles: A unified framework

Varma

Michelin

2019

Phys. Rev. Fluids

Self Cite

View full text Add to dashboard Cite

show abstract

“…In this system, long-ranged attractive and short-ranged repulsive drift velocities are generated by a balance between attraction due to chemotaxis and repulsion due to phoresis. This can be contrasted with other propelling clusters where the symmetry is broken by the shape of the cluster [37,38,53,58]. For two identical attractive swimmers, the condition to form a stationary dimer is V(0, 0, R 0 )=0, as seen in figure 9(a).…”

Section: Active Dimersmentioning

confidence: 99%

“…As active particles function under a sustained energy input within an ambient medium, their effective pair interactions are in general non-reciprocal and can systematically draw both linear and angular momentum from their surroundings. The roles of hydrodynamic flow [18][19][20][21][22][23][24], diffused solute [25][26][27][28][29], local phase change [30] and optical shadowing [31,32] as mediators of these interactions have been studied, as well as guidance by nearby boundaries [33][34][35]. Unravelling the dependence of phoretic and chemotactic effects on the surface profiles of catalyst concentration and solute-colloid interaction [8,[36][37][38] and symmetry-based classifications of pair interactions [39] have opened up the possibility of engineering active colloids with desired behaviour [40,41].…”

Section: Introductionmentioning

confidence: 99%

Pairing, waltzing and scattering of chemotactic active colloids

2019

View full text Add to dashboard Cite

We study theoretically an active colloid whose polar axis of self-propulsion rotates to point parallel (antiparallel) to an imposed chemical gradient. We show that the coupling of this 'chemotactic' ('antichemotactic') response to phoretic translational motion yields remarkable two-particle dynamics reflecting the non-central and non-reciprocal character of the interaction. A pair of mutually chemotactic colloids trap each other in a final state of fixed separation resulting in a selfpropelled active dimer. A second type of bound state is observed when the polar axes undergo periodic cycles leading to phase-locked circular motion around a common centre. A pair of swimmers with mismatched phoretic mobilities execute a dance in which they twirl around one another while moving jointly in a wide circle. For sufficiently small initial separation, the speed of self-propulsion controls the transition from bound to scattering states. Mutually anti-chemotactic swimmers always scatter apart. For the special case in which one of the two colloids has uniform surface activity we succeed in exactly classifying the fixed points underlying the bound states, and identify the bifurcations leading to transitions from one type of bound state to another. The varied dynamical behaviours are accessible by tuning the swimmer design and are summarised in state diagrams.

show abstract

“…As one of their main characteristics, these systems are intrinsically out of equilibrium allowing them to self-organize into new ordered and even functional structures. In synthetic active systems, such structures include dynamic clusters which dynamically form and break-up in low density Janus colloids [4][5][6][7][8] as well as laser driven colloids which spontaneously start to move ballistically (self-propel) when binding together [9][10][11]. Likewise, biological microswimmers form patterns such as vortices in bacterial turbulence [12][13][14][15], or swirls and microflock patterns in chiral active matter like curved polymers or sperm [16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Taming polar active matter with moving substrates: directed transport and counterpropagating macrobands

et al. 2019

View full text Add to dashboard Cite

Following the goal of using active particles as targeted cargo carriers aimed, for example, to deliver drugs towards cancer cells, the quest for the control of individual active particles with external fields is among the most explored topics in active matter. Here, we provide a scheme allowing to control collective behaviour in active matter, focusing on the fluctuating band patterns naturally occurring e.g. in the Vicsek model. We show that exposing these patterns to a travelling wave potential tames them, yet in a remarkably nontrivial way: the bands, which initially pin to the potential and comove with it, upon subsequent collisions, self-organize into a macroband, featuring a predictable transport against the direction of motion of the travelling potential. Our results provide a route to simultaneously control transport and structure, i.e. micro-versus macrophase separation, in polar active matter.

show abstract

Clustering-induced self-propulsion of isotropic autophoretic particles

Abstract: Isotropic phoretic particles do not swim individually but can achieve self-propulsion collectively by spontaneously forming clusters of anisotropic geometry.

Cited by 67 publications

References 64 publications

Modeling chemo-hydrodynamic interactions of phoretic particles: A unified framework

Modeling chemo-hydrodynamic interactions of phoretic particles: A unified framework

Pairing, waltzing and scattering of chemotactic active colloids

Taming polar active matter with moving substrates: directed transport and counterpropagating macrobands

Contact Info

Product

Resources

About