1
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Beck C, Grimaldo M, Lopez H, Da Vela S, Sohmen B, Zhang F, Oettel M, Barrat JL, Roosen-Runge F, Schreiber F, Seydel T. Short-Time Transport Properties of Bidisperse Suspensions of Immunoglobulins and Serum Albumins Consistent with a Colloid Physics Picture. J Phys Chem B 2022; 126:7400-7408. [PMID: 36112146 PMCID: PMC9527755 DOI: 10.1021/acs.jpcb.2c02380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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The crowded environment of biological systems such as
the interior
of living cells is occupied by macromolecules with a broad size distribution.
This situation of polydispersity might influence the dependence of
the diffusive dynamics of a given tracer macromolecule in a monodisperse
solution on its hydrodynamic size and on the volume fraction. The
resulting size dependence of diffusive transport crucially influences
the function of a living cell. Here, we investigate a simplified model
system consisting of two constituents in aqueous solution, namely,
of the proteins bovine serum albumin (BSA) and bovine polyclonal gamma-globulin
(Ig), systematically depending on the total volume fraction and ratio
of these constituents. From high-resolution quasi-elastic neutron
spectroscopy, the separate apparent short-time diffusion coefficients
for BSA and Ig in the mixture are extracted, which show substantial
deviations from the diffusion coefficients measured in monodisperse
solutions at the same total volume fraction. These deviations can
be modeled quantitatively using results from the short-time rotational
and translational diffusion in a two-component hard sphere system
with two distinct, effective hydrodynamic radii. Thus, we find that
a simple colloid picture well describes short-time diffusion in binary
mixtures as a function of the mixing ratio and the total volume fraction.
Notably, the self-diffusion of the smaller protein BSA in the mixture
is faster than the diffusion in a pure BSA solution, whereas the self-diffusion
of Ig in the mixture is slower than in the pure Ig solution.
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Affiliation(s)
- Christian Beck
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
- Institut Max von Laue─Paul Langevin (ILL), CS 20156, F-38042 Grenoble Cedex 9, France
| | - Marco Grimaldo
- Institut Max von Laue─Paul Langevin (ILL), CS 20156, F-38042 Grenoble Cedex 9, France
| | - Hender Lopez
- School of Physics and Optometric & Clinical Sciences, Technological University Dublin, D07 XT95 Grangegorman, Ireland
| | - Stefano Da Vela
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Benedikt Sohmen
- Institut für Angewandte Physik, Universität Tübingen, 72076 Tübingen, Germany
| | - Fajun Zhang
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Martin Oettel
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | | | - Felix Roosen-Runge
- Department of Biomedical Science and Biofilms-Research Center for Biointerfaces (BRCB), Malmö University, 20506 Malmö, Sweden
| | - Frank Schreiber
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Tilo Seydel
- Institut Max von Laue─Paul Langevin (ILL), CS 20156, F-38042 Grenoble Cedex 9, France
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2
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Laal-Dehghani N, Christopher GF. Effects of Interfacial Shear on Particle Aggregation at an Oil/Water Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:9621-9630. [PMID: 35895899 DOI: 10.1021/acs.langmuir.2c01159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Using a Stokesian dynamics simulation, the microstructure of particle aggregates at an oil/water interface with an applied Couette flow is studied. The results of the aggregation are consistent with previously published experimental work demonstrating multiple regimes of behavior based on the relative strength of shear and capillary forces. In previous work, densification of aggregates at low shear rates was theorized to occur due to short time scale fragmentation/reaggregation of aggregates with rigid particle bonds. In simulations, densification is observed at low shear rates but occurs due to local reorganization of particles due to capillary torques over long time scales. Moderate shear rates create mobile bonds between particles at shorter time scales, allowing aggregates to fragment without reaggregation into smaller isolated clusters, consistent with prior experimental work. At the highest shear rates, aggregation is inhibited completely.
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Affiliation(s)
- Nader Laal-Dehghani
- Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas 79409, United States
| | - Gordon F Christopher
- Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas 79409, United States
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3
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Vater T, Isele M, Siems U, Nielaba P. Lane and band formation of oppositely driven colloidal particles in two-dimensional ring geometries. Phys Rev E 2022; 106:024606. [PMID: 36109916 DOI: 10.1103/physreve.106.024606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 07/18/2022] [Indexed: 06/15/2023]
Abstract
We study the segregation phenomena for oppositely driven colloidal particles in two-dimensional ring geometries by means of Brownian dynamics simulations without hydrodynamic interactions. The particles interact via a repulsive Yukawa potential and are confined to a two-dimensional circular channel by hard walls, in which half of the particles are driven clockwise and the other half are driven counterclockwise. In addition to lane formation, which is commonly found in oppositely driven systems, we found band formation along the angular direction in channels with a very large radius. This indicates that a formation of lanes is prevented in the limit of channels with an infinitely large inner radius. The dependency of this segregation has been examined for the two control parameters, the interaction strength between the particles and the width of the circular channel.
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Affiliation(s)
- Tobias Vater
- Physics Department, University of Konstanz, 78467 Konstanz, Germany
| | - Marc Isele
- Physics Department, University of Konstanz, 78467 Konstanz, Germany
| | - Ullrich Siems
- Physics Department, University of Konstanz, 78467 Konstanz, Germany
| | - Peter Nielaba
- Physics Department, University of Konstanz, 78467 Konstanz, Germany
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4
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Alcázar-Cano N, Delgado-Buscalioni R. Hydrodynamics induce superdiffusive jumps of passive tracers along critical paths of random networks and colloidal gels. SOFT MATTER 2022; 18:1941-1954. [PMID: 35191454 DOI: 10.1039/d1sm01713f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We present a numerical study on the effect of hydrodynamic interactions (HI) on the diffusion of inert point tracer particles in several fixed random structures. As expected, the diffusion is hampered by the extra hydrodynamic friction introduced by the obstacle network. However, a non-trivial effect due to HI appears in the analysis of the van-Hove displacement probability close to the percolation threshold, where tracers diffuse through critical fractal paths. We show that the tracer dynamics can be split up into short and long jumps, the latter being ruled by either exponential or Gaussian van Hove distribution tails. While at short time HI slow down the tracer diffusion, at long times, hydrodynamic interactions with the obstacles increase the probability of longer jumps, which circumvent the traps of the labyrinth more easily. Notably, the relation between the anomalous diffusion exponent and the fractal dimension of the critical (intricate) paths is greater than one, which implies that the long-time (long-jump) diffusion is mildly superdiffuse. A possible reason for such a hastening of the diffusion along the network corridors is the hydrodynamically induced mobility anisotropy, which favours displacements parallel to the walls, an effect which has already been experimentally observed in collagen gels.
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Affiliation(s)
- Nerea Alcázar-Cano
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid and Condensed Matter Physics Center (IFIMAC), Madrid, Spain.
| | - Rafael Delgado-Buscalioni
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid and Condensed Matter Physics Center (IFIMAC), Madrid, Spain.
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5
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Sprenger AR, Jahanshahi S, Ivlev AV, Löwen H. Time-dependent inertia of self-propelled particles: The Langevin rocket. Phys Rev E 2021; 103:042601. [PMID: 34005997 DOI: 10.1103/physreve.103.042601] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/16/2021] [Indexed: 06/12/2023]
Abstract
Many self-propelled objects are large enough to exhibit inertial effects but still suffer from environmental fluctuations. The corresponding basic equations of motion are governed by active Langevin dynamics, which involve inertia, friction, and stochastic noise for both the translational and orientational degrees of freedom coupled via the self-propulsion along the particle orientation. In this paper, we generalize the active Langevin model to time-dependent parameters and explicitly discuss the effect of time-dependent inertia for achiral and chiral particles. Realizations of this situation are manifold, ranging from minirockets (which are self-propelled by burning their own mass), to dust particles in plasma (which lose mass by evaporating material), to walkers with expiring activity. Here we present analytical solutions for several dynamical correlation functions, such as mean-square displacement and orientational and velocity autocorrelation functions. If the parameters exhibit a slow power law in time, we obtain anomalous superdiffusion with a nontrivial dynamical exponent. Finally, we constitute the "Langevin rocket" model by including orientational fluctuations in the traditional Tsiolkovsky rocket equation. We calculate the mean reach of the Langevin rocket and discuss different mass ejection strategies to maximize it. Our results can be tested in experiments on macroscopic robotic or living particles or in self-propelled mesoscopic objects moving in media of low viscosity, such as complex plasma.
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Affiliation(s)
- Alexander R Sprenger
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, D-40225 Düsseldorf, Germany
| | - Soudeh Jahanshahi
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, D-40225 Düsseldorf, Germany
| | - Alexei V Ivlev
- Max-Planck-Institut für Extraterrestrische Physik, 85748 Garching, Germany
| | - Hartmut Löwen
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, D-40225 Düsseldorf, Germany
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6
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Popescu MN, Uspal WE, Domínguez A, Dietrich S. Effective Interactions between Chemically Active Colloids and Interfaces. Acc Chem Res 2018; 51:2991-2997. [PMID: 30403132 DOI: 10.1021/acs.accounts.8b00237] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Chemically active colloids can achieve force- and torque-free motility ("self-propulsion") via the promotion, on their surface, of catalytic chemical reactions involving the surrounding solution. Such systems are valuable both from a theoretical perspective, serving as paradigms for nonequilibrium processes, as well as from an application viewpoint, according to which active colloids are envisioned to play the role of carriers ("engines") in novel lab-on-a-chip devices. The motion of such colloids is intrinsically connected with a "chemical field", i.e., the distribution near the colloid of the number densities of the various chemical species present in the solution, and with the hydrodynamic flow of the solution around the particle. In most of the envisioned applications, and in virtually all reported experimental studies, the active colloids operate under spatial confinement (e.g., within a microfluidic channel, a drop, a free-standing liquid film, etc.). In such cases, the chemical field and the hydrodynamic flow associated with an active colloid are influenced by any nearby confining surfaces, and these disturbances couple back to the particle. Thus, an effective interaction with the spatial confinement arises. Consequently, the particle is endowed with means to perceive and to respond to its environment. Understanding these effective interactions, finding the key parameters which control them, and designing particles with desired, preconfigured responses to given environments, require interdisciplinary approaches which synergistically integrate methods and knowledge from physics, chemistry, engineering, and materials science. Here we review how, via simple models of chemical activity and self-phoretic motion, progress has recently been made in understanding the basic physical principles behind the complex behaviors exhibited by active particles near interfaces. First, we consider the occurrence of "interface-bounded" steady states of chemically active colloids near simple, nonresponsive interfaces. Examples include particles "sliding" along, or "hovering" above, a hard planar wall while inducing hydrodynamic flow of the solution. These states lay the foundations for concepts like the guidance of particles by the topography of the wall. We continue to discuss responsive interfaces: a suitable chemical patterning of a planar wall allows one to bring the particles into states of motion which are spatially localized (e.g., within chemical stripes or along chemical steps). These occur due to the wall responding to the activity-induced chemical gradients by generating osmotic flows, which encode the surface-chemistry of the wall. Finally, we discuss how, via activity-induced Marangoni stresses, long-ranged effective interactions emerge from the strong hydrodynamic response of fluid interfaces. These examples highlight how in this context a desired behavior can be potentially selected by tuning suitable parameters (e.g., the phoretic mobility of the particle, or the strength of the Marangoni stress at an interface). This can be accomplished via a judicious design of the surface chemistry of the particle and of the boundary, or by the choice of the chemical reaction in solution.
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Affiliation(s)
- Mihail N. Popescu
- Max-Planck-Institut für Intelligente Systeme, Heisenbergstr. 3, D-70569 Stuttgart, Germany
- IV. Institut für Theoretische Physik, Universität Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany
| | - William E. Uspal
- Max-Planck-Institut für Intelligente Systeme, Heisenbergstr. 3, D-70569 Stuttgart, Germany
- IV. Institut für Theoretische Physik, Universität Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany
| | - Alvaro Domínguez
- Física Teórica, Universidad de Sevilla, Apdo. 1065, 41080 Sevilla, Spain
| | - Siegfried Dietrich
- Max-Planck-Institut für Intelligente Systeme, Heisenbergstr. 3, D-70569 Stuttgart, Germany
- IV. Institut für Theoretische Physik, Universität Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany
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7
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Panzuela S, Delgado-Buscalioni R. Solvent Hydrodynamics Enhances the Collective Diffusion of Membrane Lipids. PHYSICAL REVIEW LETTERS 2018; 121:048101. [PMID: 30095966 DOI: 10.1103/physrevlett.121.048101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 05/08/2018] [Indexed: 06/08/2023]
Abstract
The collective motion of membrane lipids over hundreds of nanometers and nanoseconds plays an essential role in the formation of submicron complexes of lipids and proteins in the cell membrane. These dynamics are difficult to access experimentally and are currently poorly understood. One of the conclusions of the celebrated Saffman-Debrück (SD) theory is that lipid disturbances smaller than the Saffman length (microns) are not affected by the hydrodynamics of the embedding solvent. Using molecular dynamics and coarse-grained models with implicit hydrodynamics we show that this is not true. Hydrodynamic interactions between the membrane and the solvent strongly enhance the short-time collective diffusion of lipids at all scales. The momentum transferred between the membrane and the solvent in the normal direction (not considered by the SD theory) propagates tangentially over the membrane inducing long-ranged repulsive forces amongst lipids. As a consequence, the lipid collective diffusion coefficient increases proportionally to the disturbance wavelength. We find quantitative agreement with the predicted anomalous diffusion in quasi-two-dimensional dynamics, observed in colloids confined to a plane but embedded in a three-dimensional solvent.
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Affiliation(s)
- S Panzuela
- Department of Theoretical Condensed Matter Physics, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - R Delgado-Buscalioni
- Department of Theoretical Condensed Matter Physics, Universidad Autónoma de Madrid and Institute for Condensed Matter Physics, IFIMAC. Campus de Cantoblanco, 28049 Madrid, Spain
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8
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Domínguez A. Theory of anomalous collective diffusion in colloidal monolayers on a spherical interface. Phys Rev E 2018; 97:022607. [PMID: 29548122 DOI: 10.1103/physreve.97.022607] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Indexed: 11/07/2022]
Abstract
A planar colloidal monolayer exhibits anomalous collective diffusion due to the hydrodynamic interactions. We investigate how this behavior is affected by the curvature of the monolayer when it resides on the interface of a spherical droplet. It is found that the characteristic times of the dynamics still exhibit the same anomalous scaling as in the planar case. The spatial distribution, however, shows a difference due to the relevance of the radius of the droplet. Since for the droplet this is both a global magnitude, i.e., pertaining to the spatial extent of the spherical surface, and a local one, i.e., the radius of curvature, the question remains open as to which of these two features actually dominates in the case of a generically curved interface.
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Affiliation(s)
- Alvaro Domínguez
- Física Atómica, Molecular y Nuclear, Universidad de Sevilla, Apdo. 1065, 41080 Sevilla, Spain
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9
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Bleibel J, Domínguez A, Oettel M. Onset of anomalous diffusion in colloids confined to quasimonolayers. Phys Rev E 2017; 95:032604. [PMID: 28415209 DOI: 10.1103/physreve.95.032604] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Indexed: 06/07/2023]
Abstract
It has been recently shown that a colloidal monolayer, e.g., formed at a fluid interface or by means of a suitable confining potential, exhibits anomalous collective diffusion. This is a consequence of the hydrodynamic interactions mediated by the three-dimensional (3D) ambient fluid when the particles are confined to reside on a two-dimensional (2D) manifold. We study theoretically and with numerical simulations the crossover from normal to anomalous diffusion as the particles are, in real systems, confined by a 3D external potential and thus have the possibility to fluctuate out of the 2D manifold, thus forming a quasimonolayer.
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Affiliation(s)
- J Bleibel
- Institut für angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
- Max-Planck-Institut für Intelligente Systeme, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - Alvaro Domínguez
- Física Teórica, Universidad de Sevilla, Apdo. 1065, 41080 Sevilla, Spain
| | - M Oettel
- Institut für angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
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10
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Daddi-Moussa-Ider A, Gekle S. Hydrodynamic interaction between particles near elastic interfaces. J Chem Phys 2017; 145:014905. [PMID: 27394123 DOI: 10.1063/1.4955099] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present an analytical calculation of the hydrodynamic interaction between two spherical particles near an elastic interface such as a cell membrane. The theory predicts the frequency dependent self- and pair-mobilities accounting for the finite particle size up to the 5th order in the ratio between particle diameter and wall distance as well as between diameter and interparticle distance. We find that particle motion towards a membrane with pure bending resistance always leads to mutual repulsion similar as in the well-known case of a hard-wall. In the vicinity of a membrane with shearing resistance, however, we observe an attractive interaction in a certain parameter range which is in contrast to the behavior near a hard wall. This attraction might facilitate surface chemical reactions. Furthermore, we show that there exists a frequency range in which the pair-mobility for perpendicular motion exceeds its bulk value, leading to short-lived superdiffusive behavior. Using the analytical particle mobilities we compute collective and relative diffusion coefficients. The appropriateness of the approximations in our analytical results is demonstrated by corresponding boundary integral simulations which are in excellent agreement with the theoretical predictions.
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Affiliation(s)
- Abdallah Daddi-Moussa-Ider
- Biofluid Simulation and Modeling, Fachbereich Physik, Universität Bayreuth, Universitätsstraße 30, Bayreuth 95440, Germany
| | - Stephan Gekle
- Biofluid Simulation and Modeling, Fachbereich Physik, Universität Bayreuth, Universitätsstraße 30, Bayreuth 95440, Germany
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11
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Thorneywork AL, Aarts DGAL, Horbach J, Dullens RPA. Self-diffusion in two-dimensional binary colloidal hard-sphere fluids. Phys Rev E 2017; 95:012614. [PMID: 28208506 DOI: 10.1103/physreve.95.012614] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Indexed: 06/06/2023]
Abstract
We present a systematic experimental study of the dynamic behavior of monodisperse and bidisperse two-dimensional colloidal hard-sphere fluids. We consider the diffusive behavior of the two types of particles for systems with a variety of compositions and total area fractions. In particular, we measure the short- and long-time diffusion coefficients for both species independently. We find that the short-time self-diffusion coefficients show an approximately linear dependence on the area fraction and that the long-time self-diffusion coefficients are well described by an expression dependent upon only the area fraction and contact value of the radial distribution function. Finally, we consider the effect of composition change and find some variation in the long-time self-diffusion coefficients, which we ascribe to the complex packing effects exhibited by binary systems.
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Affiliation(s)
- Alice L Thorneywork
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Dirk G A L Aarts
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Jürgen Horbach
- Institut für Theoretische Physik II, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Roel P A Dullens
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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12
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Panzuela S, Peláez RP, Delgado-Buscalioni R. Collective colloid diffusion under soft two-dimensional confinement. Phys Rev E 2017; 95:012602. [PMID: 28208343 DOI: 10.1103/physreve.95.012602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Indexed: 06/06/2023]
Abstract
This work presents a numerical and theoretical investigation of the collective dynamics of colloids in an unbounded solution but trapped in a harmonic potential. Under strict two-dimensional confinement (infinitely stiff trap) the collective colloidal diffusion is enhanced and diverges at zero wave number (like k^{-1}), due to the hydrodynamic propagation of the confining force across the layer. The analytic solution for the collective diffusion of colloids under a Gaussian trap of width δ still shows enhanced diffusion for large wavelengths kδ<1, while a gradual transition to normal diffusion for kδ>1. At intermediate and short wavelengths, we illustrate to what extent the hydrodynamic enhancement of diffusion is masked by the conservative forces between colloids. At very large wavelengths, the collective diffusion becomes faster than the solvent momentum transport and a transition from Stokesian dynamics to inertial dynamics takes place. Using our inertial coupling method code (resolving fluid inertia), we study this transition by performing simulations at small Schmidt number. Simulations confirm theoretical predictions for the k→0 limit [Phys. Rev. E 90, 062314 (2014)PLEEE81539-375510.1103/PhysRevE.90.062314] showing negative density-density time correlations. However, at finite k simulations show deviations from the theory.
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Affiliation(s)
- S Panzuela
- Departmento de Fisica de la Materia Condensada, Universidad Autonoma de Madrid, Campus de Cantoblanco, Madrid 28949, Spain
| | - Raúl P Peláez
- Universidad Autonoma de Madrid, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain
| | - R Delgado-Buscalioni
- Departmento de Fisica de la Materia Condensada, Universidad Autonoma de Madrid, and Institute for Condensed Matter Physics, IFIMAC, Campus de Cantoblanco, Madrid 28049, Spain
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13
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Domínguez A, Malgaretti P, Popescu MN, Dietrich S. Collective dynamics of chemically active particles trapped at a fluid interface. SOFT MATTER 2016; 12:8398-8406. [PMID: 27714377 DOI: 10.1039/c6sm01468b] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Chemically active colloids generate changes in the chemical composition of their surrounding solution and thereby induce flows in the ambient fluid which affect their dynamical evolution. Here we study the many-body dynamics of a monolayer of spherically symmetric active particles trapped at a fluid-fluid interface. To this end we consider a model for the large-scale spatial distribution of particles which incorporates the direct pair interaction (including also the capillary interaction which is caused specifically by the interfacial trapping) as well as the effect of hydrodynamic interactions (including the Marangoni flow induced by the response of the interface to the chemical activity). The values of the relevant physical parameters for typical experimental realizations of such systems are estimated and various scenarios, which are predicted by our approach for the dynamics of the monolayer, are discussed. In particular, we show that the chemically-induced Marangoni flow can prevent the clustering instability driven by the capillary attraction.
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Affiliation(s)
- Alvaro Domínguez
- Física Teórica, Universidad de Sevilla, Apdo. 1065, 41080 Sevilla, Spain.
| | - P Malgaretti
- Max-Planck-Institut für Intelligente Systeme, Heisenbergstr. 3, 70569 Stuttgart, Germany and IV. Institut für Theoretische Physik, Universität Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany
| | - M N Popescu
- Max-Planck-Institut für Intelligente Systeme, Heisenbergstr. 3, 70569 Stuttgart, Germany and IV. Institut für Theoretische Physik, Universität Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany
| | - S Dietrich
- Max-Planck-Institut für Intelligente Systeme, Heisenbergstr. 3, 70569 Stuttgart, Germany and IV. Institut für Theoretische Physik, Universität Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany
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14
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Bleibel J, Domínguez A, Oettel M. A dynamic DFT approach to generalized diffusion equations in a system with long-ranged and hydrodynamic interactions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:244021. [PMID: 27115236 DOI: 10.1088/0953-8984/28/24/244021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We build on an existing approximation scheme to the Smoluchowski equation in order to derive a dynamic density functional theory (DDFT) including two-body hydrodynamic interactions. A generalized diffusion equation and a wavenumber-dependent diffusion coefficient D(k) are derived by linearization in the density fluctuations. The result is applied to a colloidal monolayer at a fluid interface, having bulk-like hydrodynamic interactions and/or interacting via long-ranged capillary forces. In these cases, D(k) shows characteristic singularities as [Formula: see text]. The consequences of these singularities are studied by means of analytical perturbation theory, numerical solution of DDFT and simulations for an explicit example: the capillary collapse of a finite, disk-like distribution of particles. There is in general a good agreement between DDFT and simulations if the initial density distributions for the theoretical prediction correspond to the actual initial configurations of simulations, rather than to an average over them. Otherwise, discrepancies arise that are discussed in detail.
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Affiliation(s)
- Johannes Bleibel
- Institut für Angewandte Physik, Auf der Morgenstelle 10, Eberhard Karls Universität, 72076 Tübingen, Germany. Max-Planck-Institut für Intelligente Systeme, Heisenbergstr. 3, 70569 Stuttgart, Germany
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15
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Malgaretti P, Popescu MN, Dietrich S. Active colloids at fluid interfaces. SOFT MATTER 2016; 12:4007-4023. [PMID: 27025167 DOI: 10.1039/c6sm00367b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
If an active Janus particle is trapped at the interface between a liquid and a fluid, its self-propelled motion along the interface is affected by a net torque on the particle due to the viscosity contrast between the two adjacent fluid phases. For a simple model of an active, spherical Janus colloid we analyze the conditions under which translation occurs along the interface and we provide estimates of the corresponding persistence length. We show that under certain conditions the persistence length of such a particle is significantly larger than the corresponding one in the bulk liquid, which is in line with the trends observed in recent experimental studies.
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Affiliation(s)
- P Malgaretti
- Max-Planck-Institut fur Intelligente Systeme, Theory of Inhomogeneous Condensed Matter, Heisenbergstrasse 3, Stuttgart, Germany.
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Thorneywork AL, Rozas RE, Dullens RPA, Horbach J. Effect of Hydrodynamic Interactions on Self-Diffusion of Quasi-Two-Dimensional Colloidal Hard Spheres. PHYSICAL REVIEW LETTERS 2015; 115:268301. [PMID: 26765032 DOI: 10.1103/physrevlett.115.268301] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Indexed: 06/05/2023]
Abstract
We compare experimental results from a quasi-two-dimensional colloidal hard sphere fluid to a Monte Carlo simulation of hard disks with small particle displacements. The experimental short-time self-diffusion coefficient D(S) scaled by the diffusion coefficient at infinite dilution, D(0), strongly depends on the area fraction, pointing to significant hydrodynamic interactions at short times in the experiment, which are absent in the simulation. In contrast, the area fraction dependence of the experimental long-time self-diffusion coefficient D(L)/D(0) is in quantitative agreement with D(L)/D(0) obtained from the simulation. This indicates that the reduction in the particle mobility at short times due to hydrodynamic interactions does not lead to a proportional reduction in the long-time self-diffusion coefficient. Furthermore, the quantitative agreement between experiment and simulation at long times indicates that hydrodynamic interactions effectively do not affect the dependence of D(L)/D(0) on the area fraction. In light of this, we discuss the link between structure and long-time self-diffusion in terms of a configurational excess entropy and do not find a simple exponential relation between these quantities for all fluid area fractions.
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Affiliation(s)
- Alice L Thorneywork
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Park Road, Oxford OX1 3QZ, United Kingdom
| | - Roberto E Rozas
- Institut für Theoretische Physik II: Soft Matter, Heinrich Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
- Departamento de Física, Universidad del Bío-Bío, Collao 1202, Casilla 5C, Concepción, Chile
| | - Roel P A Dullens
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Park Road, Oxford OX1 3QZ, United Kingdom
| | - Jürgen Horbach
- Institut für Theoretische Physik II: Soft Matter, Heinrich Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
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17
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Español P, Donev A. Coupling a nano-particle with isothermal fluctuating hydrodynamics: Coarse-graining from microscopic to mesoscopic dynamics. J Chem Phys 2015; 143:234104. [DOI: 10.1063/1.4936775] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Affiliation(s)
- Pep Español
- Dept. Física Fundamental, Universidad Nacional de Educación a Distancia, Aptdo. 60141, E-28080 Madrid, Spain
| | - Aleksandar Donev
- Dept. Física Fundamental, Universidad Nacional de Educación a Distancia, Aptdo. 60141, E-28080 Madrid, Spain
- Courant Institute of Mathematical Sciences, New York University, 251 Mercer Street, New York, New York 10012, USA
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de Graaf J, Peter T, Fischer LP, Holm C. The Raspberry model for hydrodynamic interactions revisited. II. The effect of confinement. J Chem Phys 2015; 143:084108. [PMID: 26328819 DOI: 10.1063/1.4928503] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The so-called "raspberry" model refers to the hybrid lattice-Boltzmann (LB) and Langevin molecular dynamics schemes for simulating the dynamics of suspensions of colloidal particles, originally developed by Lobaskin and Dünweg [New J. Phys. 6, 54 (2004)], wherein discrete surface points are used to achieve fluid-particle coupling. In this paper, we present a follow up to our study of the effectiveness of the raspberry model in reproducing hydrodynamic interactions in the Stokes regime for spheres arranged in a simple-cubic crystal [Fischer et al., J. Chem. Phys. 143, 084107 (2015)]. Here, we consider the accuracy with which the raspberry model is able to reproduce such interactions for particles confined between two parallel plates. To this end, we compare our LB simulation results to established theoretical expressions and finite-element calculations. We show that there is a discrepancy between the translational and rotational mobilities when only surface coupling points are used, as also found in Part I of our joint publication. We demonstrate that adding internal coupling points to the raspberry can be used to correct said discrepancy in confining geometries as well. Finally, we show that the raspberry model accurately reproduces hydrodynamic interactions between a spherical colloid and planar walls up to roughly one LB lattice spacing.
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Affiliation(s)
- Joost de Graaf
- Institute for Computational Physics (ICP), University of Stuttgart, Allmandring 3, 70569 Stuttgart, Germany
| | - Toni Peter
- Institute for Computational Physics (ICP), University of Stuttgart, Allmandring 3, 70569 Stuttgart, Germany
| | - Lukas P Fischer
- Institute for Computational Physics (ICP), University of Stuttgart, Allmandring 3, 70569 Stuttgart, Germany
| | - Christian Holm
- Institute for Computational Physics (ICP), University of Stuttgart, Allmandring 3, 70569 Stuttgart, Germany
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19
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Li Y, Huo Y, Zhang Y. Two dimensional colloidal crystals formed by particle self-assembly due to hydrodynamic interaction. Colloid Polym Sci 2015. [DOI: 10.1007/s00396-015-3636-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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20
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Begam N, Chandran S, Sprung M, Basu JK. Anomalous Viscosity Reduction and Hydrodynamic Interactions of Polymeric Nanocolloids in Polymers. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b00759] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nafisa Begam
- Department
of Physics, Indian Institute of Science, Bangalore, 560 012, India
| | - Sivasurender Chandran
- Institute
of Physics, Albert-Ludwigs-University of Freiburg, 79104 Freiburg, Germany
| | - M. Sprung
- Deutsches Elektronen Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - J. K. Basu
- Department
of Physics, Indian Institute of Science, Bangalore, 560 012, India
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21
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Bleibel J, Domínguez A, Oettel M. 3D hydrodynamic interactions lead to divergences in 2D diffusion. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:194113. [PMID: 25923320 DOI: 10.1088/0953-8984/27/19/194113] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We investigate the influence of 3D hydrodynamic interactions on confined colloidal suspensions, where only the colloids are restricted to one or two dimensions. In the absence of static interactions among the colloids, i.e., an ideal gas of colloidal particles with a finite hydrodynamic radius, we find a divergent collective diffusion coefficient. The origin of the divergence is traced back to the dimensional mismatch of 3D hydrodynamic interactions and the colloidal particles moving only in 1D or 2D. Our results from theory are confirmed by Stokesian dynamics simulations and supported by light scattering observational data for particles at a fluid interface.
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Affiliation(s)
- Johannes Bleibel
- Institut für Angewandte Physik, Auf der Morgenstelle 10, Eberhard Karls Universität, 72076 Tübingen, Germany. Max-Planck-Institut für Intelligente Systeme, Heisenbergstr. 3, 70569 Stuttgart, Germany
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Domínguez A. Signature of time-dependent hydrodynamic interactions on collective diffusion in colloidal monolayers. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 90:062314. [PMID: 25615100 DOI: 10.1103/physreve.90.062314] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Indexed: 06/04/2023]
Abstract
It has been shown recently that the coefficient of collective diffusion in a colloidal monolayer is divergent due to the hydrodynamic interactions mediated by the ambient fluid in bulk. The analysis is extended to allow for time-dependent hydrodynamic interactions. Observational features specific to this time dependency are predicted. The possible experimental detection in the dynamics of the monolayer is discussed.
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Affiliation(s)
- Alvaro Domínguez
- Física Teórica, Universidad de Sevilla, Apdo. 1065, 41080 Sevilla, Spain
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Bleibel J, Domínguez A, Oettel M, Dietrich S. Capillary attraction induced collapse of colloidal monolayers at fluid interfaces. SOFT MATTER 2014; 10:4091-4109. [PMID: 24740385 DOI: 10.1039/c3sm53070a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We investigate the evolution of a system of colloidal particles, trapped at a fluid interface and interacting via capillary attraction, as a function of the range of capillary interactions and temperature. We address the collapse of an initially homogeneous particle distribution and of a radially symmetric (disk-shaped) distribution of finite size, both theoretically by using a perturbative approach inspired by cosmological models and numerically by means of Brownian dynamics (BD) and dynamical density functional theory (DDFT). The results are summarized in a "dynamical phase diagram", describing a smooth crossover from a collective (gravitational-like) collapse to local (spinodal-like) clustering. In this crossover region, the evolution exhibits a peculiar shock wave behavior at the outer rim of the contracting, disk-shaped distribution.
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Affiliation(s)
- J Bleibel
- Institut für Angewandte Physik, Auf der Morgenstelle 10, Eberhard Karls Universität, 72076 Tübingen, Germany.
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