Active Particle Accumulation at Boundaries: A Strategy to Measure Contact Angles

Simmchen, Juliane; Malgaretti, Paolo

doi:10.1002/cnma.201700135

Cited by 9 publications

(9 citation statements)

References 20 publications

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“…Indeed, in Ref. [79], authors determine the local contact angle of the droplet by measuring their distance from the edge of the droplet.…”

Section: Phoretic Colloids Close To Fluid Interfacesmentioning

confidence: 99%

Phoretic colloids close to and trapped at fluid interfaces

Malgaretti¹,

Harting²

2021

Preprint

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The active motion of phoretic colloids leads them to accumulate at boundaries and interfaces. Such an excess accumulation, with respect to their passive counterparts, makes the dynamics of phoretic colloids particularly sensitive to the presence of boundaries and pave new routes to externally control their single particle as well as collective behavior. Here we review some recent theoretical results about the dynamics of phoretic colloids close to and adsorbed at fluid interfaces in particular highlighting similarities and differences with respect to solid-fluid interfaces.

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“…Indeed, in Ref. [79], authors determine the local contact angle of the droplet by measuring their distance from the edge of the droplet.…”

Section: Phoretic Colloids Close To Fluid Interfacesmentioning

confidence: 99%

Phoretic colloids close to and trapped at fluid interfaces

Malgaretti¹,

Harting²

2021

Preprint

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“…The experimental studies of active matter on interfaces has mostly been performed in specially engineered cases, for example we studied the particle behavior close to a wedge formed by a droplet and a solid surface. 13 Dietrich et al studied the swimming of active Janus particles distributed at the liquid−liquid interface by spreading out an isopropanol solution directly at the boundary. 14 They found different wetting behaviors for the two phases, and they correlated the orientations of the particles with the two populations of particle speed they had observed.…”

Section: ■ Introductionmentioning

confidence: 99%

“…However, the creation of stable and observable fluid interfaces is not a trivial task. The experimental studies of active matter on interfaces has mostly been performed in specially engineered cases, for example we studied the particle behavior close to a wedge formed by a droplet and a solid surface . Dietrich et al studied the swimming of active Janus particles distributed at the liquid–liquid interface by spreading out an isopropanol solution directly at the boundary .…”

Section: Introductionmentioning

confidence: 99%

Study of Active Janus Particles in the Presence of an Engineered Oil–Water Interface

et al. 2020

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We present a systematic study of motion of Pt@ SiO 2 Janus particles at a liquid−liquid interface. A special microfluidic trap is used for creating such an interface. The increased surface energy of the large surface results in partial wetting of the substrate, leaving patches of oil on the glass surface. This allows us to directly compare the motion at the two interfaces, i.e., oil−water and solid−water interface within the same setting, guaranteeing identical conditions in terms of additional parameters. The propulsion behavior of Janus particles is found to be quantitatively similar at both surfaces. The interplay of reaction product absorption by oil, slip locking by surfactant, microscale friction, lubrication efficiency, and potential Marangoni effect controls the resemblance of motion characteristics at the two interfaces. Additionally, we also observed guidance effect on the Janus particles by the pinning line of oil patches, similar to solid side walls.

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“…For example, sperm cells have been observed to accumulate at solid walls [6] and bacteria swim in circles when close to substrates [7] or fluid interfaces [8]. Moreover, synthetic swimmers have been shown to be sensitive to both solid boundaries [9][10][11][12][13][14][15][16][17] and liquid interfaces [18][19][20][21][22][23][24]. Concerning synthetic swimmers, the presence of boundaries and interfaces is particularly relevant for self-phoretic colloids.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulations of self-diffusiophoretic colloids at fluid interfaces

et al. 2020

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The dynamics of active colloids is very sensitive to the presence of boundaries and interfaces which therefore can be used to control their motion. Here we analyze the dynamics of active colloids adsorbed at a fluid-fluid interface. By using a mesoscopic numerical approach which relies on an approximated numerical solution of the Navier-Stokes equation, we show that when adsorbed at a fluid interface, an active colloid experiences a net torque even in the absence of a viscosity contrast between the two adjacent fluids. In particular, we study the dependence of this torque on the contact angle of the colloid with the fluid-fluid interface and on its surface properties. We rationalize our results via an approximate approach which accounts for the appearance of a local friction coefficient. By providing insight into the dynamics of active colloids adsorbed at fluid interfaces, our results are relevant for two-dimensional self assembly and emulsion stabilization by means of active colloids. * malgaretti@is.mpg.de

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Active Particle Accumulation at Boundaries: A Strategy to Measure Contact Angles

Cited by 9 publications

References 20 publications

Phoretic colloids close to and trapped at fluid interfaces

Phoretic colloids close to and trapped at fluid interfaces

Study of Active Janus Particles in the Presence of an Engineered Oil–Water Interface

Numerical simulations of self-diffusiophoretic colloids at fluid interfaces

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