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Li Z, Ye H, Lin J, Ouyang Z. Analysis of the number of topological defects in active nematic fluids under applied shear flow. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2024; 47:43. [PMID: 38900310 DOI: 10.1140/epje/s10189-024-00437-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 05/31/2024] [Indexed: 06/21/2024]
Abstract
The number of topological defects in the shear flow of active nematic fluids is numerically investigated in this study. The evolution of the flow state of extensile active nematic fluids is explored by increasing the activity of active nematic fluids. Evidently, medium-activity active nematic fluids exhibit a highly ordered vortex lattice fluid state. However, high-activity active nematic fluids exhibit a meso-scale turbulent flow accompanied by topological defects. The number of topological defects (Ndef) increases with increasing shear Reynolds number (Res). Fluid viscosity strongly influences Ndef, while the influence of fluid density is relatively weak. Ndef decreases with increasing activity length scale (lζ) value. A small Res value strongly influences Ndef, whereas a large lζ value only weakly influences Ndef. As the activity increases, Ndef in contractile active nematic fluids becomes larger than that of extensile active nematic fluids.
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Affiliation(s)
- Zhenna Li
- State Key Laboratory of Fluid Power Transmission and Control, Zhejiang University, Hangzhou, 310027, China
| | - Hao Ye
- State Key Laboratory of Fluid Power Transmission and Control, Zhejiang University, Hangzhou, 310027, China
| | - Jianzhong Lin
- State Key Laboratory of Fluid Power Transmission and Control, Zhejiang University, Hangzhou, 310027, China.
- Zhejiang Provincial Engineering Research Center for the Safety of Pressure Vessel and Pipeline, Ningbo University, Ningbo, 315201, China.
| | - Zhenyu Ouyang
- Zhejiang Provincial Engineering Research Center for the Safety of Pressure Vessel and Pipeline, Ningbo University, Ningbo, 315201, China
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2
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Thampi SP, Stratford K, Henrich O. Simulating dynamics of ellipsoidal particles using lattice Boltzmann method. Phys Rev E 2024; 109:065302. [PMID: 39020973 DOI: 10.1103/physreve.109.065302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 05/21/2024] [Indexed: 07/20/2024]
Abstract
Anisotropic particles are often encountered in different fields of soft matter and complex fluids. In this work, we present an implementation of the coupled hydrodynamics of solid ellipsoidal particles and the surrounding fluid using the lattice Boltzmann method. A standard link-based mechanism is used to implement the solid-fluid boundary conditions. We develop an implicit method to update the position and orientation of the ellipsoid. This exploits the relations between the quaternion which describes the ellipsoid's orientation and the ellipsoid's angular velocity to obtain a stable and robust dynamic update. The proposed algorithm is validated by looking at four scenarios: (i) the steady translational velocity of a spheroid subject to an external force in different orientations, (ii) the drift of an inclined spheroid subject to an imposed force, (iii) three-dimensional rotational motions in a simple shear flow (Jeffrey's orbits), and (iv) developed fluid flows and self-propulsion exhibited by a spheroidal microswimmer. In all cases the comparison of numerical results shows good agreement with known analytical solutions, irrespective of the choice of the fluid properties, geometrical parameters, and lattice Boltzmann model, thus demonstrating the robustness of the proposed algorithm.
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3
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Caporusso CB, Cugliandolo LF, Digregorio P, Gonnella G, Suma A. Phase separation kinetics and cluster dynamics in two-dimensional active dumbbell systems. SOFT MATTER 2024; 20:4208-4225. [PMID: 38741521 DOI: 10.1039/d4sm00200h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Molecular dynamics simulations were employed to investigate the phase separation process of a two-dimensional active Brownian dumbbell model. We evaluated the time dependence of the typical size of the dense component using the scaling properties of the structure factor, along with the averaged number of clusters and their radii of gyration. The growth observed is faster than in active disk models, and this effect is further enhanced under stronger activity. Next, we focused on studying the hexatic order of the clusters. The length associated with the orientational order increases algebraically with time and faster than for spherical active Brownian particles. Under weak active forces, most clusters exhibit a uniform internal orientational order. However, under strong forces, large clusters consist of domains with different orientational orders. We demonstrated that the latter configurations are not stable, and given sufficient time to evolve, they eventually achieve homogeneous configurations as well. No gas bubbles are formed within the clusters, even when there are patches of different hexatic order. Finally, attention was directed towards the geometry and motion of the clusters themselves. By employing a tracking algorithm, we showed that clusters smaller than the typical size at the observation time exhibit regular shapes, while larger ones display fractal characteristics. In between collisions or break-ups, the clusters behave as solid bodies. Their centers of mass undergo circular motion, with radii increasing with the cluster size. The angular velocity of the center of mass equals that of the constituents with respect to their center of mass. These observations were rationalised with a simple mechanical model.
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Affiliation(s)
- C B Caporusso
- Dipartimento Interateneo di Fisica, Università degli Studi di Bari, via Amendola 173, Bari, I-70126, Italy
- INFN, Sezione di Bari, via Amendola 173, Bari, I-70126, Italy
| | - L F Cugliandolo
- CNRS, Laboratoire de Physique Théorique et Hautes Energies, LPTHE, Sorbonne Université, F-75005 Paris, France
- Institut Universitaire de France, 1 rue Descartes, 75231 Paris Cedex 05, France
| | - P Digregorio
- Departement de Fisica de la Materia Condensada, Facultat de Fisica, Universitat de Barcelona, Martí i Franquès 1, E08028 Barcelona, Spain.
- UBICS University of Barcelona Institute of Complex Systems, Martí i Franquès 1, E08028 Barcelona, Spain
| | - G Gonnella
- Dipartimento Interateneo di Fisica, Università degli Studi di Bari, via Amendola 173, Bari, I-70126, Italy
- INFN, Sezione di Bari, via Amendola 173, Bari, I-70126, Italy
| | - A Suma
- Dipartimento Interateneo di Fisica, Università degli Studi di Bari, via Amendola 173, Bari, I-70126, Italy
- INFN, Sezione di Bari, via Amendola 173, Bari, I-70126, Italy
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4
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Redford SA, Colen J, Shivers JL, Zemsky S, Molaei M, Floyd C, Ruijgrok PV, Vitelli V, Bryant Z, Dinner AR, Gardel ML. Motor crosslinking augments elasticity in active nematics. SOFT MATTER 2024; 20:2480-2490. [PMID: 38385209 PMCID: PMC10933839 DOI: 10.1039/d3sm01176c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 01/12/2024] [Indexed: 02/23/2024]
Abstract
In active materials, uncoordinated internal stresses lead to emergent long-range flows. An understanding of how the behavior of active materials depends on mesoscopic (hydrodynamic) parameters is developing, but there remains a gap in knowledge concerning how hydrodynamic parameters depend on the properties of microscopic elements. In this work, we combine experiments and multiscale modeling to relate the structure and dynamics of active nematics composed of biopolymer filaments and molecular motors to their microscopic properties, in particular motor processivity, speed, and valency. We show that crosslinking of filaments by both motors and passive crosslinkers not only augments the contributions to nematic elasticity from excluded volume effects but dominates them. By altering motor kinetics we show that a competition between motor speed and crosslinking results in a nonmonotonic dependence of nematic flow on motor speed. By modulating passive filament crosslinking we show that energy transfer into nematic flow is in large part dictated by crosslinking. Thus motor proteins both generate activity and contribute to nematic elasticity. Our results provide new insights for rationally engineering active materials.
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Affiliation(s)
- Steven A Redford
- The Graduate Program in Biophysical Sciences, University of Chicago, Chicago, IL 60637, USA
- Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637, USA.
| | - Jonathan Colen
- Department of Physics, University of Chicago, Chicago, IL 60637, USA
- James Franck Institute, University of Chicago, Chicago, IL 60637, USA
| | - Jordan L Shivers
- James Franck Institute, University of Chicago, Chicago, IL 60637, USA
- Department of Chemistry, University of Chicago, Chicago, IL 60637, USA
| | - Sasha Zemsky
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
- Program in Biophysics, Stanford University, Stanford, CA 94305, USA
| | - Mehdi Molaei
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL 60637, USA
| | - Carlos Floyd
- James Franck Institute, University of Chicago, Chicago, IL 60637, USA
- Department of Chemistry, University of Chicago, Chicago, IL 60637, USA
| | - Paul V Ruijgrok
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Vincenzo Vitelli
- Department of Physics, University of Chicago, Chicago, IL 60637, USA
- James Franck Institute, University of Chicago, Chicago, IL 60637, USA
| | - Zev Bryant
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Aaron R Dinner
- Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637, USA.
- James Franck Institute, University of Chicago, Chicago, IL 60637, USA
- Department of Chemistry, University of Chicago, Chicago, IL 60637, USA
| | - Margaret L Gardel
- Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637, USA.
- Department of Physics, University of Chicago, Chicago, IL 60637, USA
- James Franck Institute, University of Chicago, Chicago, IL 60637, USA
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL 60637, USA
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5
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Pal A, Jaju SJ, Kumaran V. Defect interactions in a two-dimensional sheared lamellar mesophase. SOFT MATTER 2024; 20:1499-1522. [PMID: 38265310 DOI: 10.1039/d3sm01516e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
The interaction between two edge dislocations in a sheared lyotropic lamellar liquid-crystalline medium is examined. The model is a mesoscale hydrodynamic model based on a free-energy functional that is minimised for a sinusoidal concentration modulation coupled with concentration and momentum equations. The defect dynamics are analysed as a function of the system size and the Ericksen number, the ratio of the shear stress and the characteristic free-energy density for deformation. Three different regimes are observed as the Ericksen number is increased when the edge dislocations are sheared towards each other, such that there is compression of layers between the defects: (a) defect motion that reduces the cross-stream separation till there is a steady spacing with plug flow between the defects, (b) defect attraction and cancellation resulting in a well-aligned state, and (c) defect creation due to a compressional instability between the defects resulting in an increase in the disorder. When the edge dislocations are sheared away from each other, such that there is extension of the layers between the defects, two distinct regimes are observed as the Ericksen number is increased: (a) bending of layers and a plug flow between the defects at their initial separation, and (b) buckling of the layers leading to creation of more defects and a dynamical steady state between defect creation and cancellation. These regimes are found to be robust for different values of the system size, from 32 to 128 layers, and for different values of the dimensionless groups that characterise the ratio of mass/momentum convection and diffusion.
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Affiliation(s)
- A Pal
- Department of Chemical Engineering, Indian Institute of Science, Bangalore 560 012, India.
| | - S J Jaju
- Sankhyasutra Labs Ltd., 13th Floor, M2 Block, Manyata Embassy Business Park, Nagavara, Bengaluru, Karnataka 560045, India
| | - V Kumaran
- Department of Chemical Engineering, Indian Institute of Science, Bangalore 560 012, India.
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6
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Caporusso CB, Negro G, Suma A, Digregorio P, Carenza LN, Gonnella G, Cugliandolo LF. Phase behaviour and dynamics of three-dimensional active dumbbell systems. SOFT MATTER 2024; 20:923-939. [PMID: 38189452 DOI: 10.1039/d3sm01030a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
We present a comprehensive numerical study of the phase behavior and dynamics of a three-dimensional active dumbbell system with attractive interactions. We demonstrate that attraction is essential for the system to exhibit nontrivial phases. We construct a detailed phase diagram by exploring the effects of the system's activity, density, and attraction strength. We identify several distinct phases, including a disordered, a gel, and a completely phase-separated phase. Additionally, we discover a novel dynamical phase, that we name percolating network, which is characterized by the presence of a spanning network of connected dumbbells. In the phase-separated phase we characterize numerically and describe analytically the helical motion of the dense cluster.
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Affiliation(s)
- C B Caporusso
- Dipartimento Interateneo di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari, I-70126, Italy.
| | - G Negro
- Dipartimento Interateneo di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari, I-70126, Italy.
| | - A Suma
- Dipartimento Interateneo di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari, I-70126, Italy.
| | - P Digregorio
- Departement de Fisica de la Materia Condensada, Facultat de Fisica, Universitat de Barcelona, Martí i Franquès 1, E08028 Barcelona, Spain
- UBICS University of Barcelona Institute of Complex Systems, Martí i Franquès 1, E08028 Barcelona, Spain
| | - L N Carenza
- Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, The Netherlands
- Department of Physics, Koç University, Rumelifeneri Yolu, 34450 Saryer, Istanbul, Turkey
| | - G Gonnella
- Dipartimento Interateneo di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari, I-70126, Italy.
| | - L F Cugliandolo
- CNRS, Laboratoire de Physique Théorique et Hautes Energies, LPTHE, Sorbonne Université, F-75005 Paris, France
- Institut Universitaire de France, 1 rue Descartes, 75231 Paris Cedex 05, France
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7
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Armengol-Collado JM, Carenza LN, Giomi L. Hydrodynamics and multiscale order in confluent epithelia. eLife 2024; 13:e86400. [PMID: 38189410 PMCID: PMC10963026 DOI: 10.7554/elife.86400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 01/05/2024] [Indexed: 01/09/2024] Open
Abstract
We formulate a hydrodynamic theory of confluent epithelia: i.e. monolayers of epithelial cells adhering to each other without gaps. Taking advantage of recent progresses toward establishing a general hydrodynamic theory of p-atic liquid crystals, we demonstrate that collectively migrating epithelia feature both nematic (i.e. p = 2) and hexatic (i.e. p = 6) orders, with the former being dominant at large and the latter at small length scales. Such a remarkable multiscale liquid crystal order leaves a distinct signature in the system's structure factor, which exhibits two different power-law scaling regimes, reflecting both the hexagonal geometry of small cells clusters and the uniaxial structure of the global cellular flow. We support these analytical predictions with two different cell-resolved models of epithelia - i.e. the self-propelled Voronoi model and the multiphase field model - and highlight how momentum dissipation and noise influence the range of fluctuations at small length scales, thereby affecting the degree of cooperativity between cells. Our construction provides a theoretical framework to conceptualize the recent observation of multiscale order in layers of Madin-Darby canine kidney cells and pave the way for further theoretical developments.
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Affiliation(s)
| | | | - Luca Giomi
- Instituut-Lorentz, Leiden UniversityLeidenNetherlands
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8
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Negro G, Gonnella G, Lamura A, Busuioc S, Sofonea V. Growth regimes in three-dimensional phase separation of liquid-vapor systems. Phys Rev E 2024; 109:015305. [PMID: 38366419 DOI: 10.1103/physreve.109.015305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 12/28/2023] [Indexed: 02/18/2024]
Abstract
The liquid-vapor phase separation is investigated via lattice Boltzmann simulations in three dimensions. After expressing length and time scales in reduced physical units, we combined data from several large simulations (on 512^{3} nodes) with different values of viscosity, surface tension, and temperature, to obtain a single curve of rescaled length l[over ̂] as a function of rescaled time t[over ̂]. We find evidence of the existence of kinetic and inertial regimes with growth exponents α_{d}=1/2 and α_{i}=2/3 over several time decades, with a crossover from α_{d} to α_{i} at t[over ̂]≃1. This allows us to rule out the existence of a viscous regime with α_{v}=1 in three-dimensional liquid-vapor isothermal phase separation, differently from what happens in binary fluid mixtures. An in-depth analysis of the kinetics of the phase separation process, as well as a characterization of the morphology and the flow properties, are further presented in order to provide clues into the dynamics of the phase-separation process.
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Affiliation(s)
- G Negro
- Dipartimento di Fisica, Universitá degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, I-70126 Bari, Italy
| | - G Gonnella
- Dipartimento di Fisica, Universitá degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, I-70126 Bari, Italy
| | - A Lamura
- Istituto Applicazioni Calcolo, CNR, Via Amendola 122/D, I-70126 Bari, Italy
| | - S Busuioc
- Institute for Advanced Environmental Research, West University of Timişoara, Bd. Vasile Pârvan 4, 300223 Timişoara, Romania
| | - V Sofonea
- Center for Fundamental and Advanced Technical Research, Romanian Academy, Bd. Mihai Viteazul 24, 300223 Timişoara, Romania
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9
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Xu H, Nejad MR, Yeomans JM, Wu Y. Geometrical control of interface patterning underlies active matter invasion. Proc Natl Acad Sci U S A 2023; 120:e2219708120. [PMID: 37459530 PMCID: PMC10372614 DOI: 10.1073/pnas.2219708120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 06/16/2023] [Indexed: 07/20/2023] Open
Abstract
Interaction between active materials and the boundaries of geometrical confinement is key to many emergent phenomena in active systems. For living active matter consisting of animal cells or motile bacteria, the confinement boundary is often a deformable interface, and it has been unclear how activity-induced interface dynamics might lead to morphogenesis and pattern formation. Here, we studied the evolution of bacterial active matter confined by a deformable boundary. We found that an ordered morphological pattern emerged at the interface characterized by periodically spaced interfacial protrusions; behind the interfacial protrusions, bacterial swimmers self-organized into multicellular clusters displaying +1/2 nematic defects. Subsequently, a hierarchical sequence of transitions from interfacial protrusions to creeping branches allowed the bacterial active drop to rapidly invade surrounding space with a striking self-similar branch pattern. We found that this interface patterning is geometrically controlled by the local curvature of the interface, a phenomenon we denote as collective curvature sensing. Using a continuum active model, we revealed that the collective curvature sensing arises from enhanced active stresses near high-curvature regions, with the active length scale setting the characteristic distance between the interfacial protrusions. Our findings reveal a protrusion-to-branch transition as a unique mode of active matter invasion and suggest a strategy to engineer pattern formation of active materials.
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Affiliation(s)
- Haoran Xu
- Department of Physics, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, People’s Republic of China
- Shenzhen Research Institute, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, People’s Republic of China
| | - Mehrana R. Nejad
- Department of Physics, The Rudolf Peierls Centre for Theoretical Physics, University of Oxford, OxfordOX1 3PU, United Kingdom
| | - Julia M. Yeomans
- Department of Physics, The Rudolf Peierls Centre for Theoretical Physics, University of Oxford, OxfordOX1 3PU, United Kingdom
| | - Yilin Wu
- Department of Physics, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, People’s Republic of China
- Shenzhen Research Institute, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, People’s Republic of China
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10
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Pal A, Jaju SJ, Kumaran V. The relationship between structure and rheology in a three-dimensional sheared lamellar mesophase. SOFT MATTER 2023. [PMID: 37401735 DOI: 10.1039/d3sm00455d] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/05/2023]
Abstract
The evolution of a lamellar mesophase from an initially disordered state under shear is examined using simulations of a mesoscale model based on a concentration field ψ that distinguishes the hydrophilic and hydrophobic components. The Landau-Ginzburg free-energy functional is augmented by a term that is minimised for sinusoidal modulations in the concentration field with wavelength λ = (2π/k), and the dynamical equations are the model H equations. The structure and rheology are determined by the relative magnitudes of the diffusion time for coarsening, (λ2/D) and the inverse of the strain rate -1, and the Ericksen number, which is the ratio of the shear stress and the layer stiffness. When the diffusion time is small compared with the inverse of the strain rate, there is a local formation of misaligned layers, which are deformed by the imposed flow. There is near-perfect ordering with isolated defects at low values of the Ericksen number, but the defects result in a significant increase in viscosity due to the high layer stiffness. At high values of the Ericksen number, the concentration field is deformed by the mean shear before layers form via diffusion. Cylindrical structures aligned along the flow direction form after about 8-10 strain units, and these evolve into layers with disorder through diffusion perpendicular to the flow. The layers are not perfectly ordered, even after hundreds of strain units, due to the creation and destruction of defects via shear. The excess viscosity is low because the layer stiffness is small compared with the applied shear at a high Ericksen number. This study provides guidance on how the material parameters and imposed flow can be tailored to achieve the desired rheological behaviour.
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Affiliation(s)
- A Pal
- Department of Chemical Engineering, Indian Institute of Science, Bangalore 560 012, India.
| | - S J Jaju
- Sankhyasutra Labs Ltd., 13th Floor, M2 Block, Manyata Embassy Business Park, Nagavara, Bengaluru, Karnataka 560045, India
| | - V Kumaran
- Department of Chemical Engineering, Indian Institute of Science, Bangalore 560 012, India.
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11
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Negro G, Carenza LN, Gonnella G, Mackay F, Morozov A, Marenduzzo D. Yield-stress transition in suspensions of deformable droplets. SCIENCE ADVANCES 2023; 9:eadf8106. [PMID: 37256946 PMCID: PMC10413676 DOI: 10.1126/sciadv.adf8106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 04/27/2023] [Indexed: 06/02/2023]
Abstract
Yield-stress materials, which require a sufficiently large forcing to flow, are currently ill-understood theoretically. To gain insight into their yielding transition, we study numerically the rheology of a suspension of deformable droplets in 2D. We show that the suspension displays yield-stress behavior, with droplets remaining motionless below a critical body-force. In this phase, droplets jam to form an amorphous structure, whereas they order in the flowing phase. Yielding is linked to a percolation transition in the contacts of droplet-droplet overlaps and requires strict conservation of the droplet area to exist. Close to the transition, we find strong oscillations in the droplet motion that resemble those found experimentally in confined colloidal glasses. We show that even when droplets are static, the underlying solvent moves by permeation so that the viscosity of the composite system is never truly infinite, and its value ceases to be a bulk material property of the system.
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Affiliation(s)
- Giuseppe Negro
- Dipartimento di Fisica, Universitá degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari I-70126, Italy
- School of Physics and Astronomy (SUPA), University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, UK
| | - Livio Nicola Carenza
- Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, Netherlands
| | - Giuseppe Gonnella
- Dipartimento di Fisica, Universitá degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari I-70126, Italy
| | - Fraser Mackay
- School of Physics and Astronomy (SUPA), University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, UK
| | - Alexander Morozov
- School of Physics and Astronomy (SUPA), University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, UK
| | - Davide Marenduzzo
- School of Physics and Astronomy (SUPA), University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, UK
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12
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Hoffmann LA, Carenza LN, Giomi L. Tuneable defect-curvature coupling and topological transitions in active shells. SOFT MATTER 2023; 19:3423-3435. [PMID: 37129899 DOI: 10.1039/d2sm01370c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Recent experimental observations have suggested that topological defects can facilitate the creation of sharp features in developing embryos. Whereas these observations echo established knowledge about the interplay between geometry and topology in two-dimensional passive liquid crystals, the role of activity has mostly remained unexplored. In this article we focus on deformable shells consisting of either polar or nematic active liquid crystals and demonstrate that activity renders the mechanical coupling between defects and curvature much more involved and versatile than previously thought. Using a combination of linear stability analysis and three-dimensional computational fluid dynamics, we demonstrate that such a coupling can in fact be tuned, depending on the type of liquid crystal order, the specific structure of the defect (i.e. asters or vortices) and the nature of the active forces. In polar systems, this can drive a spectacular transition from spherical to toroidal topology, in the presence of large extensile activity. Our analysis strengthens the idea that defects could serve as topological morphogens and provides a number of predictions that could be tested in in vitro studies, for instance in the context of organoids.
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Affiliation(s)
- Ludwig A Hoffmann
- Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, The Netherlands.
| | - Livio Nicola Carenza
- Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, The Netherlands.
| | - Luca Giomi
- Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, The Netherlands.
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13
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Puggioni L, Boffetta G, Musacchio S. Flocking turbulence of microswimmers in confined domains. Phys Rev E 2023; 107:055107. [PMID: 37329031 DOI: 10.1103/physreve.107.055107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 05/05/2023] [Indexed: 06/18/2023]
Abstract
We extensively study the Toner-Tu-Swift-Hohenberg model of motile active matter by means of direct numerical simulations in a two-dimensional confined domain. By exploring the space of parameters of the model we investigate the emergence of a new state of active turbulence which occurs when the aligning interactions and the self-propulsion of the swimmers are strong. This regime of flocking turbulence is characterized by a population of few strong vortices, each surrounded by an island of coherent flocking motion. The energy spectrum of flocking turbulence displays a power-law scaling with an exponent which depends weakly on the model parameters. By increasing the confinement we observe that the system, after a long transient characterized by power-law-distributed transition times, switches to the ordered state of a single giant vortex.
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Affiliation(s)
- L Puggioni
- Dipartimento di Fisica and INFN, Università degli Studi di Torino, via P. Giuria 1, 10125 Torino, Italy
| | - G Boffetta
- Dipartimento di Fisica and INFN, Università degli Studi di Torino, via P. Giuria 1, 10125 Torino, Italy
- Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan
| | - S Musacchio
- Dipartimento di Fisica and INFN, Università degli Studi di Torino, via P. Giuria 1, 10125 Torino, Italy
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14
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Negro G, Carenza LN, Gonnella G, Marenduzzo D, Orlandini E. Topological phases and curvature-driven pattern formation in cholesteric shells. SOFT MATTER 2023; 19:1987-2000. [PMID: 36847796 DOI: 10.1039/d2sm01347a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
We study the phase behaviour of cholesteric liquid crystal shells with different geometries. We compare the cases of tangential anchoring and no anchoring at the surface, focussing on the former case, which leads to a competition between the intrinsic tendency of the cholesteric to twist and the anchoring free energy which suppresses it. We then characterise the topological phases arising close to the isotropic-cholesteric transition. These typically consist of quasi-crystalline or amorphous tessellations of the surface by half-skyrmions, which are stable at lower and larger shell sizes, respectively. For ellipsoidal shells, defects in the tessellation couple to a local curvature, and according to the shell size, they either migrate to the poles or distribute uniformly on the surface. For toroidal shells, the variations in the local curvature of the surface stabilise heterogeneous phases where cholesteric or isotropic patterns coexist with hexagonal lattices of half-skyrmions.
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Affiliation(s)
- G Negro
- Dipartimento di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari, I-70126, Italy
| | - L N Carenza
- Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, The Netherlands.
| | - G Gonnella
- Dipartimento di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari, I-70126, Italy
| | - D Marenduzzo
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, UK
| | - E Orlandini
- Dipartimento di Fisica e Astronomia, Università di Padova, 35131 Padova, Italy
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15
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Krommydas D, Carenza LN, Giomi L. Hydrodynamic Enhancement of p-atic Defect Dynamics. PHYSICAL REVIEW LETTERS 2023; 130:098101. [PMID: 36930922 DOI: 10.1103/physrevlett.130.098101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 01/19/2023] [Indexed: 06/18/2023]
Abstract
We investigate numerically and analytically the effects of hydrodynamics on the dynamics of topological defects in p-atic liquid crystals, i.e., two-dimensional liquid crystals with p-fold rotational symmetry. Importantly, we find that hydrodynamics fuels a generic passive self-propulsion mechanism for defects of winding number s=(p-1)/p and arbitrary p. Strikingly, we discover that hydrodynamics always accelerates the annihilation dynamics of pairs of ±1/p defects and that, contrary to expectations, this effect increases with p. Our Letter paves the way toward understanding cell intercalation and other remodeling events in epithelial layers.
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Affiliation(s)
- Dimitrios Krommydas
- Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, Netherlands
| | - Livio Nicola Carenza
- Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, Netherlands
| | - Luca Giomi
- Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, Netherlands
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16
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The crucial role of adhesion in the transmigration of active droplets through interstitial orifices. Nat Commun 2023; 14:1096. [PMID: 36841803 PMCID: PMC9968312 DOI: 10.1038/s41467-023-36656-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Accepted: 02/09/2023] [Indexed: 02/26/2023] Open
Abstract
Active fluid droplets are a class of soft materials exhibiting autonomous motion sustained by an energy supply. Such systems have been shown to capture motility regimes typical of biological cells and are ideal candidates as building-block for the fabrication of soft biomimetic materials of interest in pharmacology, tissue engineering and lab on chip devices. While their behavior is well established in unconstrained environments, much less is known about their dynamics under strong confinement. Here, we numerically study the physics of a droplet of active polar fluid migrating within a microchannel hosting a constriction with adhesive properties, and report evidence of a striking variety of dynamic regimes and morphological features, whose properties crucially depend upon droplet speed and elasticity, degree of confinement within the constriction and adhesiveness to the pore. Our results suggest that non-uniform adhesion forces are instrumental in enabling the crossing through narrow orifices, in contrast to larger gaps where a careful balance between speed and elasticity is sufficient to guarantee the transition. These observations may be useful for improving the design of artificial micro-swimmers, of interest in material science and pharmaceutics, and potentially for cell sorting in microfluidic devices.
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17
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Floyd C, Vaikuntanathan S, Dinner AR. Simulating structured fluids with tensorial viscoelasticity. J Chem Phys 2023; 158:054906. [PMID: 36754798 DOI: 10.1063/5.0123470] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
We consider an immersed elastic body that is actively driven through a structured fluid by a motor or an external force. The behavior of such a system generally cannot be solved analytically, necessitating the use of numerical methods. However, current numerical methods omit important details of the microscopic structure and dynamics of the fluid, which can modulate the magnitudes and directions of viscoelastic restoring forces. To address this issue, we develop a simulation platform for modeling viscoelastic media with tensorial elasticity. We build on the lattice Boltzmann algorithm and incorporate viscoelastic forces, elastic immersed objects, a microscopic orientation field, and coupling between viscoelasticity and the orientation field. We demonstrate our method by characterizing how the viscoelastic restoring force on a driven immersed object depends on various key parameters as well as the tensorial character of the elastic response. We find that the restoring force depends non-monotonically on the rate of diffusion of the stress and the size of the object. We further show how the restoring force depends on the relative orientation of the microscopic structure and the pulling direction. These results imply that accounting for previously neglected physical features, such as stress diffusion and the microscopic orientation field, can improve the realism of viscoelastic simulations. We discuss possible applications and extensions to the method.
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Affiliation(s)
- Carlos Floyd
- Chicago Center for Theoretical Chemistry, University of Chicago, Chicago, Illinois 60637, USA
| | | | - Aaron R Dinner
- Chicago Center for Theoretical Chemistry, University of Chicago, Chicago, Illinois 60637, USA
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18
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Abdollahzadeh Y, Mehrpooya M, Mousavian SMA, Moqtaderi H. Modeling and simulation of nanofluid in low Reynolds numbers using two-phase Lattice Boltzmann method based on mixture model. Chem Eng Res Des 2023. [DOI: 10.1016/j.cherd.2023.02.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
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19
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Negro G, Caporusso CB, Digregorio P, Gonnella G, Lamura A, Suma A. Hydrodynamic effects on the liquid-hexatic transition of active colloids. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2022; 45:75. [PMID: 36098879 PMCID: PMC9470657 DOI: 10.1140/epje/s10189-022-00230-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 08/25/2022] [Indexed: 05/06/2023]
Abstract
We study numerically the role of hydrodynamics in the liquid-hexatic transition of active colloids at intermediate activity, where motility induced phase separation (MIPS) does not occur. We show that in the case of active Brownian particles (ABP), the critical density of the transition decreases upon increasing the particle's mass, enhancing ordering, while self-propulsion has the opposite effect in the activity regime considered. Active hydrodynamic particles (AHP), instead, undergo the liquid-hexatic transition at higher values of packing fraction [Formula: see text] than the corresponding ABP, suggesting that hydrodynamics have the net effect of disordering the system. At increasing densities, close to the hexatic-liquid transition, we found in the case of AHP the appearance of self-sustained organized motion with clusters of particles moving coherently.
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Affiliation(s)
- G Negro
- Dipartimento di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari, 70126, Italy
| | - C B Caporusso
- Dipartimento di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari, 70126, Italy.
| | - P Digregorio
- Centre Européen de Calcul Atomique et Moléculaire (CECAM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Batochimie, Avenue Forel 2, 1015, Lausanne, Switzerland
| | - G Gonnella
- Dipartimento di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari, 70126, Italy
| | - A Lamura
- Istituto Applicazioni Calcolo, CNR, Via Amendola 122/D, 70126, Bari, Italy
| | - A Suma
- Dipartimento di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari, 70126, Italy
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20
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Palacios LS, Scagliarini A, Pagonabarraga I. A lattice Boltzmann model for self-diffusiophoretic particles near and at liquid-liquid interfaces. J Chem Phys 2022; 156:224105. [PMID: 35705409 DOI: 10.1063/5.0087203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We introduce a novel mesoscopic computational model based on a multiphase-multicomponent lattice Boltzmann method for the simulation of self-phoretic particles in the presence of liquid-liquid interfaces. Our model features fully resolved solvent hydrodynamics, and, thanks to its versatility, it can handle important aspects of the multiphysics of the problem, including particle wettability and differential solubility of the product in the two liquid phases. The method is extensively validated in simple numerical experiments, whose outcome is theoretically predictable, and then applied to the study of the behavior of active particles next to and trapped at interfaces. We show that their motion can be variously steered by tuning relevant control parameters, such as the phoretic mobilities, the contact angle, and the product solubility.
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Affiliation(s)
- Lucas S Palacios
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 10-12, 08028 Barcelona, Spain
| | - Andrea Scagliarini
- Istituto per le Applicazioni del Calcolo, CNR-Via dei Taurini 19, 00185 Rome, Italy
| | - Ignacio Pagonabarraga
- Departament de Física de la Materia Condensada, Universitat de Barcelona, Carrer Martí i Franqués 1, 08028 Barcelona, Spain
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21
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Hoffmann LA, Carenza LN, Eckert J, Giomi L. Theory of defect-mediated morphogenesis. SCIENCE ADVANCES 2022; 8:eabk2712. [PMID: 35427161 PMCID: PMC9012457 DOI: 10.1126/sciadv.abk2712] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Growing experimental evidence indicates that topological defects could serve as organizing centers in the morphogenesis of tissues. Here, we provide a quantitative explanation for this phenomenon, rooted in the buckling theory of deformable active polar liquid crystals. Using a combination of linear stability analysis and computational fluid dynamics, we demonstrate that active layers, such as confined cell monolayers, are unstable to the formation of protrusions in the presence of disclinations. The instability originates from an interplay between the focusing of the elastic forces, mediated by defects, and the renormalization of the system's surface tension by the active flow. The posttransitional regime is also characterized by several complex morphodynamical processes, such as oscillatory deformations, droplet nucleation, and active turbulence. Our findings offer an explanation of recent observations on tissue morphogenesis and shed light on the dynamics of active surfaces in general.
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Affiliation(s)
- Ludwig A. Hoffmann
- Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA, Leiden, Netherlands
| | - Livio Nicola Carenza
- Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA, Leiden, Netherlands
| | - Julia Eckert
- Physics of Life Processes, Leiden Institute of Physics, Universiteit Leiden, P.O. Box 9506, 2300 RA, Leiden, Netherlands
| | - Luca Giomi
- Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA, Leiden, Netherlands
- Corresponding author.
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22
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Zhang C, Liang H, Guo Z, Wang LP. Discrete unified gas-kinetic scheme for the conservative Allen-Cahn equation. Phys Rev E 2022; 105:045317. [PMID: 35590655 DOI: 10.1103/physreve.105.045317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 04/07/2022] [Indexed: 06/15/2023]
Abstract
In this paper, two discrete unified gas-kinetic scheme (DUGKS) methods with piecewise-parabolic flux reconstruction are presented for the conservative Allen-Cahn equation (CACE). One includes a temporal derivative of the order parameter in the force term while the other does not include temporal derivative in the force term but results in a modified CACE with additional terms. In the context of DUGKS, the continuum equations recovered from the piecewise-linear and piecewise-parabolic reconstructions for the fluxes at cell faces are subsequently derived. It is proved that the resulting equation with the piecewise-linear reconstruction is a first-order approximation to the discrete velocity kinetic equation due to the presence of the force term and the nonconservation property of the momentum of the collision model. To guarantee second-order accuracy of DUGKS, the piecewise-parabolic reconstruction for numerical flux is proposed. To validate the accuracy of the present DUGKS with the proposed flux evaluation, several benchmark problems, including the diagonal translation of a circular interface, the rotation of a Zalesak disk and the deformation of a circular interface, have been simulated. Numerical results show that the accuracy of both proposed DUGKS methods is almost comparable and improved compared with the DUGKS with linear flux reconstruction scheme.
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Affiliation(s)
- Chunhua Zhang
- Guangdong Provincial Key Laboratory of Turbulence Research and Applications, Department of Mechanics and Aerospace Engineering, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China
| | - Hong Liang
- Department of Physics, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Zhaoli Guo
- State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Lian-Ping Wang
- Guangdong Provincial Key Laboratory of Turbulence Research and Applications, Department of Mechanics and Aerospace Engineering, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China
- Center for Complex Flows and Soft Matter Research, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China
- Guangdong-Hong Kong-Macao Joint Laboratory for Data-Driven Fluid Mechanics and Engineering Applications, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China
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23
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Li Q, Yu Y, Luo KH. Improved three-dimensional thermal multiphase lattice Boltzmann model for liquid-vapor phase change. Phys Rev E 2022; 105:025308. [PMID: 35291096 DOI: 10.1103/physreve.105.025308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 01/27/2022] [Indexed: 06/14/2023]
Abstract
Modeling liquid-vapor phase change using the lattice Boltzmann (LB) method has attracted significant attention in recent years. In this paper, we propose an improved three-dimensional thermal multiphase LB model for simulating liquid-vapor phase change. The proposed model has the following features. First, it is still within the framework of the thermal LB method using a temperature distribution function and therefore retains the fundamental advantages of the thermal LB method. Second, in the existing thermal LB models for liquid-vapor phase change, the finite-difference computations of the gradient terms ∇·u and ∇T usually require special treatment at boundary nodes, while in the proposed thermal LB model these two terms are calculated locally. Moreover, in some of the existing thermal LB models, the error term ∂_{t_{0}}(Tu) is eliminated by adding local correction terms to the collision process in the moment space, which causes these thermal LB models to be limited to the D2Q9 lattice in two dimensions and the D3Q15 or D3Q19 lattice in three dimensions. Conversely, the proposed model does not suffer from such an error term and therefore the thermal LB equation can be constructed on the D3Q7 lattice, which simplifies the model and improves the computational efficiency. Numerical simulations are carried out to validate the accuracy and efficiency of the proposed thermal multiphase LB model for simulating liquid-vapor phase change.
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Affiliation(s)
- Qing Li
- School of Energy Science and Engineering, Central South University, Changsha 410083, China
| | - Y Yu
- School of Energy Science and Engineering, Central South University, Changsha 410083, China
| | - Kai H Luo
- Department of Mechanical Engineering, University College London, London WC1E 7JE, United Kingdom
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24
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Nejad MR, Yeomans JM. Active Extensile Stress Promotes 3D Director Orientations and Flows. PHYSICAL REVIEW LETTERS 2022; 128:048001. [PMID: 35148135 DOI: 10.1103/physrevlett.128.048001] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 08/21/2021] [Accepted: 12/24/2021] [Indexed: 06/14/2023]
Abstract
We use numerical simulations and linear stability analysis to study an active nematic layer where the director is allowed to point out of the plane. Our results highlight the difference between extensile and contractile systems. Contractile stress suppresses the flows perpendicular to the layer and favors in-plane orientations of the director. By contrast extensile stress promotes instabilities that can turn the director out of the plane, leaving behind a population of distinct, in-plane regions that continually elongate and divide. This supports extensile forces as a mechanism for the initial stages of layer formation in living systems, and we show that a planar drop with extensile (contractile) activity grows into three dimensions (remains in two dimensions). The results also explain the propensity of disclination lines in three dimensional active nematics to be of twist type in extensile or wedge type in contractile materials.
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Affiliation(s)
- Mehrana R Nejad
- The Rudolf Peierls Centre for Theoretical Physics, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Julia M Yeomans
- The Rudolf Peierls Centre for Theoretical Physics, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
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25
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Carenza LN, Gonnella G, Marenduzzo D, Negro G, Orlandini E. Cholesteric Shells: Two-Dimensional Blue Fog and Finite Quasicrystals. PHYSICAL REVIEW LETTERS 2022; 128:027801. [PMID: 35089738 DOI: 10.1103/physrevlett.128.027801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 09/22/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
We study the phase behavior of a quasi-two-dimensional cholesteric liquid crystal shell. We characterize the topological phases arising close to the isotropic-cholesteric transition and show that they differ in a fundamental way from those observed on a flat geometry. For spherical shells, we discover two types of quasi-two-dimensional topological phases: finite quasicrystals and amorphous structures, both made up of mixtures of polygonal tessellations of half-skyrmions. These structures generically emerge instead of regular double twist lattices because of geometric frustration, which disallows a regular hexagonal tiling of curved space. For toroidal shells, the variations in the local curvature of the surface stabilizes heterogeneous phases where cholesteric patterns coexist with hexagonal lattices of half-skyrmions. Quasicrystals and amorphous and heterogeneous structures could be sought experimentally by self-assembling cholesteric shells on the surface of emulsion droplets.
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Affiliation(s)
- L N Carenza
- Dipartimento di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari I-70126, Italy
- Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, Netherlands
| | - G Gonnella
- Dipartimento di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari I-70126, Italy
| | - D Marenduzzo
- SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, United Kingdom
| | - G Negro
- Dipartimento di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari I-70126, Italy
| | - E Orlandini
- Dipartimento di Fisica e Astronomia, Università di Padova and INFN, Sezione di Padova, Via Marzolo 8, 35131 Padova, Italy
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26
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Liebchen B, Mukhopadhyay AK. Interactions in active colloids. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 34:083002. [PMID: 34788232 DOI: 10.1088/1361-648x/ac3a86] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 11/16/2021] [Indexed: 06/13/2023]
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.
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Affiliation(s)
- Benno Liebchen
- Institute for Condensed Matter Physics, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - Aritra K Mukhopadhyay
- Institute for Condensed Matter Physics, Technische Universität Darmstadt, 64289 Darmstadt, Germany
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27
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Tiribocchi A, Montessori A, Durve M, Bonaccorso F, Lauricella M, Succi S. Dynamics of polydisperse multiple emulsions in microfluidic channels. Phys Rev E 2021; 104:065112. [PMID: 35030928 DOI: 10.1103/physreve.104.065112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 12/09/2021] [Indexed: 06/14/2023]
Abstract
Multiple emulsions are a class of soft fluid in which small drops are immersed within a larger one and stabilized over long periods of time by a surfactant. We recently showed that, if a monodisperse multiple emulsion is subject to a pressure-driven flow, a wide variety of nonequilibrium steady states emerges at late times, whose dynamics relies on a complex interplay between hydrodynamic interactions and multibody collisions among internal drops. In this work, we use lattice Boltzmann simulations to study the dynamics of polydisperse double emulsions driven by a Poiseuille flow within a microfluidic channel. Our results show that their behavior is critically affected by multiple factors, such as initial position, polydispersity index, and area fraction occupied within the emulsion. While at low area fraction inner drops may exhibit either a periodic rotational motion (at low polydispersity) or arrange into nonmotile configurations (at high polydispersity) located far from each other, at larger values of area fraction they remain in tight contact and move unidirectionally. This decisively conditions their close-range dynamics, quantitatively assessed through a time-efficiency-like factor. Simulations also unveil the key role played by the capsule, whose shape changes can favor the formation of a selected number of nonequilibrium states in which both motile and nonmotile configurations are found.
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Affiliation(s)
- A Tiribocchi
- Istituto per le Applicazioni del Calcolo CNR, via dei Taurini 19, 00185 Rome, Italy
| | - A Montessori
- Istituto per le Applicazioni del Calcolo CNR, via dei Taurini 19, 00185 Rome, Italy
| | - M Durve
- Center for Life Nano Science@La Sapienza, Istituto Italiano di Tecnologia, 00161 Roma, Italy
| | - F Bonaccorso
- Istituto per le Applicazioni del Calcolo CNR, via dei Taurini 19, 00185 Rome, Italy
- Center for Life Nano Science@La Sapienza, Istituto Italiano di Tecnologia, 00161 Roma, Italy
- Department of Physics and INFN, University of Rome "Tor Vergata," Via della Ricerca Scientifica, 00133 Rome, Italy
| | - M Lauricella
- Istituto per le Applicazioni del Calcolo CNR, via dei Taurini 19, 00185 Rome, Italy
| | - S Succi
- Istituto per le Applicazioni del Calcolo CNR, via dei Taurini 19, 00185 Rome, Italy
- Center for Life Nano Science@La Sapienza, Istituto Italiano di Tecnologia, 00161 Roma, Italy
- Institute for Applied Computational Science, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
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28
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Zitz S, Scagliarini A, Harting J. Lattice Boltzmann simulations of stochastic thin film dewetting. Phys Rev E 2021; 104:034801. [PMID: 34654097 DOI: 10.1103/physreve.104.034801] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 08/11/2021] [Indexed: 11/07/2022]
Abstract
We study numerically the effect of thermal fluctuations and of variable fluid-substrate interactions on the spontaneous dewetting of thin liquid films. To this aim, we use a recently developed lattice Boltzmann method for thin liquid film flows, equipped with a properly devised stochastic term. While it is known that thermal fluctuations yield shorter rupture times, we show that this is a general feature of hydrophilic substrates, irrespective of the contact angle θ. The ratio between deterministic and stochastic rupture times, though, decreases with θ. Finally, we discuss the case of fluctuating thin film dewetting on chemically patterned substrates and its dependence on the form of the wettability gradients.
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Affiliation(s)
- S Zitz
- Helmholtz Institute Erlangen-Nürnberg for Renewable Energy, Forschungszentrum Jülich, Fürther Strasse 248, 90429 Nürnberg, Germany.,Department of Chemical and Biological Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg, Fürther Straße 248, 90429 Nürnberg, Germany
| | - A Scagliarini
- Institute for Applied Mathematics "M. Picone" (IAC), Consiglio Nazionale delle Ricerche (CNR), Via dei Taurini 19, 00185 Rome, Italy.,INFN, sezione Roma "Tor Vergata", via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - J Harting
- Helmholtz Institute Erlangen-Nürnberg for Renewable Energy, Forschungszentrum Jülich, Fürther Strasse 248, 90429 Nürnberg, Germany.,Department of Chemical and Biological Engineering and Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Fürther Straße 248, 90429 Nürnberg, Germany
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Montessori A, Tiribocchi A, Bogdan M, Bonaccorso F, Lauricella M, Guzowski J, Succi S. Translocation Dynamics of High-Internal Phase Double Emulsions in Narrow Channels. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:9026-9033. [PMID: 34291636 PMCID: PMC8503876 DOI: 10.1021/acs.langmuir.1c01026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 06/18/2021] [Indexed: 06/13/2023]
Abstract
We numerically study the translocation dynamics of double emulsion drops with multiple close-packed inner droplets within constrictions. Such liquid architectures, which we refer to as HIPdEs (high-internal phase double emulsions), consist of a ternary fluid, in which monodisperse droplets are encapsulated within a larger drop in turn immersed in a bulk fluid. Extensive two-dimensional lattice Boltzmann simulations show that if the area fraction of the internal drops is close to the packing fraction limit of hard spheres and the height of the channel is much smaller than the typical size of the emulsion, the crossing yields permanent shape deformations persistent over long periods of time. Morphological changes and rheological response are quantitatively assessed in terms of the structure of the velocity field, circularity of the emulsion, and rate of energy dissipated by viscous forces. Our results may be used to improve the design of soft mesoscale porous materials, which employ HIPdEs as templates for tissue engineering applications.
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Affiliation(s)
- Andrea Montessori
- Istituto
per le Applicazioni del Calcolo CNR, Via dei Taurini 19, Rome 00185, Italy
| | - Adriano Tiribocchi
- Istituto
per le Applicazioni del Calcolo CNR, Via dei Taurini 19, Rome 00185, Italy
- Center
for Life Nanoscience at la Sapienza, Istituto
Italiano di Tecnologia, Viale Regina Elena 295, Rome 00161, Italy
| | - Michał Bogdan
- Institute
of Physical Chemistry, Polish Academy of
Sciences, Kasprzaka 44/52, Warsaw 01-224, Poland
| | - Fabio Bonaccorso
- Istituto
per le Applicazioni del Calcolo CNR, Via dei Taurini 19, Rome 00185, Italy
- Center
for Life Nanoscience at la Sapienza, Istituto
Italiano di Tecnologia, Viale Regina Elena 295, Rome 00161, Italy
- Dipartimento
di Fisica, Università degli Studi
di Roma “Tor Vergata”, Via della Ricerca Scientifica 1, Rome 00133, Italy
| | - Marco Lauricella
- Istituto
per le Applicazioni del Calcolo CNR, Via dei Taurini 19, Rome 00185, Italy
| | - Jan Guzowski
- Institute
of Physical Chemistry, Polish Academy of
Sciences, Kasprzaka 44/52, Warsaw 01-224, Poland
| | - Sauro Succi
- Istituto
per le Applicazioni del Calcolo CNR, Via dei Taurini 19, Rome 00185, Italy
- Center
for Life Nanoscience at la Sapienza, Istituto
Italiano di Tecnologia, Viale Regina Elena 295, Rome 00161, Italy
- Institute
for Applied Computational Science, Harvard
John A. Paulson School of Engineering and Applied Sciences, Cambridge, Massachusetts 02138, United States
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30
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Kuron M, Stewart C, de Graaf J, Holm C. An extensible lattice Boltzmann method for viscoelastic flows: complex and moving boundaries in Oldroyd-B fluids. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:1. [PMID: 33555445 PMCID: PMC7870644 DOI: 10.1140/epje/s10189-020-00005-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 12/14/2020] [Indexed: 05/26/2023]
Abstract
Most biological fluids are viscoelastic, meaning that they have elastic properties in addition to the dissipative properties found in Newtonian fluids. Computational models can help us understand viscoelastic flow, but are often limited in how they deal with complex flow geometries and suspended particles. Here, we present a lattice Boltzmann solver for Oldroyd-B fluids that can handle arbitrarily shaped fixed and moving boundary conditions, which makes it ideally suited for the simulation of confined colloidal suspensions. We validate our method using several standard rheological setups and additionally study a single sedimenting colloid, also finding good agreement with the literature. Our approach can readily be extended to constitutive equations other than Oldroyd-B. This flexibility and the handling of complex boundaries hold promise for the study of microswimmers in viscoelastic fluids.
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Affiliation(s)
- Michael Kuron
- Institute for Computational Physics, University of Stuttgart, Allmandring 3, 70569, Stuttgart, Germany.
| | - Cameron Stewart
- Institute for Computational Physics, University of Stuttgart, Allmandring 3, 70569, Stuttgart, Germany
| | - Joost de Graaf
- Institute for Theoretical Physics, Center for Extreme Matter and Emergent Phenomena, Utrecht University, Princetonplein 5, 3584 CC, Utrecht, The Netherlands
| | - Christian Holm
- Institute for Computational Physics, University of Stuttgart, Allmandring 3, 70569, Stuttgart, Germany
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31
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Tiribocchi A, Montessori A, Lauricella M, Bonaccorso F, Succi S, Aime S, Milani M, Weitz DA. The vortex-driven dynamics of droplets within droplets. Nat Commun 2021; 12:82. [PMID: 33398018 PMCID: PMC7782531 DOI: 10.1038/s41467-020-20364-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 11/20/2020] [Indexed: 01/29/2023] Open
Abstract
Understanding the fluid-structure interaction is crucial for an optimal design and manufacturing of soft mesoscale materials. Multi-core emulsions are a class of soft fluids assembled from cluster configurations of deformable oil-water double droplets (cores), often employed as building-blocks for the realisation of devices of interest in bio-technology, such as drug-delivery, tissue engineering and regenerative medicine. Here, we study the physics of multi-core emulsions flowing in microfluidic channels and report numerical evidence of a surprisingly rich variety of driven non-equilibrium states (NES), whose formation is caused by a dipolar fluid vortex triggered by the sheared structure of the flow carrier within the microchannel. The observed dynamic regimes range from long-lived NES at low core-area fraction, characterised by a planetary-like motion of the internal drops, to short-lived ones at high core-area fraction, in which a pre-chaotic motion results from multi-body collisions of inner drops, as combined with self-consistent hydrodynamic interactions. The onset of pre-chaotic behavior is marked by transitions of the cores from one vortex to another, a process that we interpret as manifestations of the system to maximize its entropy by filling voids, as they arise dynamically within the capsule.
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Affiliation(s)
- A. Tiribocchi
- grid.25786.3e0000 0004 1764 2907Center for Life Nano Science@La Sapienza, Istituto Italiano di Tecnologia, Roma, 00161 Italy ,grid.5326.20000 0001 1940 4177Istituto per le Applicazioni del Calcolo CNR, via dei Taurini 19, Rome, 00185 Italy
| | - A. Montessori
- grid.5326.20000 0001 1940 4177Istituto per le Applicazioni del Calcolo CNR, via dei Taurini 19, Rome, 00185 Italy
| | - M. Lauricella
- grid.5326.20000 0001 1940 4177Istituto per le Applicazioni del Calcolo CNR, via dei Taurini 19, Rome, 00185 Italy
| | - F. Bonaccorso
- grid.25786.3e0000 0004 1764 2907Center for Life Nano Science@La Sapienza, Istituto Italiano di Tecnologia, Roma, 00161 Italy ,grid.5326.20000 0001 1940 4177Istituto per le Applicazioni del Calcolo CNR, via dei Taurini 19, Rome, 00185 Italy
| | - S. Succi
- grid.25786.3e0000 0004 1764 2907Center for Life Nano Science@La Sapienza, Istituto Italiano di Tecnologia, Roma, 00161 Italy ,grid.5326.20000 0001 1940 4177Istituto per le Applicazioni del Calcolo CNR, via dei Taurini 19, Rome, 00185 Italy ,grid.38142.3c000000041936754XInstitute for Applied Computational Science, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138 USA
| | - S. Aime
- grid.38142.3c000000041936754XInstitute for Applied Computational Science, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138 USA ,grid.15736.360000 0001 1882 0021Matiére Molle et Chimie, Ecole Supérieure de Physique et Chimie Industrielles, Paris, 75005 France
| | - M. Milani
- grid.4708.b0000 0004 1757 2822Universitá degli Studi di Milano, via Celoria 16, Milano, 20133 Italy
| | - D. A. Weitz
- grid.38142.3c000000041936754XInstitute for Applied Computational Science, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138 USA ,grid.38142.3c000000041936754XDepartment of Physics, Harvard University, Cambridge, MA 02138 USA
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32
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Durve M, Bonaccorso F, Montessori A, Lauricella M, Tiribocchi A, Succi S. Tracking droplets in soft granular flows with deep learning techniques. EUROPEAN PHYSICAL JOURNAL PLUS 2021; 136:864. [PMID: 34458055 PMCID: PMC8380117 DOI: 10.1140/epjp/s13360-021-01849-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 08/07/2021] [Indexed: 05/09/2023]
Abstract
The state-of-the-art deep learning-based object recognition YOLO algorithm and object tracking DeepSORT algorithm are combined to analyze digital images from fluid dynamic simulations of multi-core emulsions and soft flowing crystals and to track moving droplets within these complex flows. The YOLO network was trained to recognize the droplets with synthetically prepared data, thereby bypassing the labor-intensive data acquisition process. In both applications, the trained YOLO + DeepSORT procedure performs with high accuracy on the real data from the fluid simulations, with low error levels in the inferred trajectories of the droplets and independently computed ground truth. Moreover, using commonly used desktop GPUs, the developed application is capable of analyzing data at speeds that exceed the typical image acquisition rates of digital cameras (30 fps), opening the interesting prospect of realizing a low-cost and practical tool to study systems with many moving objects, mostly but not exclusively, biological ones. Besides its practical applications, the procedure presented here marks the first step towards the automatic extraction of effective equations of motion of many-body soft flowing systems.
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Affiliation(s)
- Mihir Durve
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy
| | - Fabio Bonaccorso
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy
- Istituto per le Applicazioni del Calcolo CNR, via dei Taurini 19, Rome, Italy
- Department of Physics and INFN, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Andrea Montessori
- Istituto per le Applicazioni del Calcolo CNR, via dei Taurini 19, Rome, Italy
| | - Marco Lauricella
- Istituto per le Applicazioni del Calcolo CNR, via dei Taurini 19, Rome, Italy
| | - Adriano Tiribocchi
- Istituto per le Applicazioni del Calcolo CNR, via dei Taurini 19, Rome, Italy
| | - Sauro Succi
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy
- Istituto per le Applicazioni del Calcolo CNR, via dei Taurini 19, Rome, Italy
- Institute for Applied Computational Science, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, USA
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33
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Thijssen K, Nejad MR, Yeomans JM. Role of Friction in Multidefect Ordering. PHYSICAL REVIEW LETTERS 2020; 125:218004. [PMID: 33275020 DOI: 10.1103/physrevlett.125.218004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 07/30/2020] [Accepted: 10/22/2020] [Indexed: 06/12/2023]
Abstract
We use continuum simulations to study the impact of friction on the ordering of defects in an active nematic. Even in a frictionless system, +1/2 defects tend to align side by side and orient antiparallel reflecting their propensity to form, and circulate with, flow vortices. Increasing friction enhances the effectiveness of the defect-defect interactions, and defects form dynamically evolving, large-scale, positionally, and orientationally ordered structures, which can be explained as a competition between hexagonal packing, preferred by the -1/2 defects, and rectangular packing, preferred by the +1/2 defects.
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Affiliation(s)
- Kristian Thijssen
- The Rudolf Peierls Centre for Theoretical Physics, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Mehrana R Nejad
- The Rudolf Peierls Centre for Theoretical Physics, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Julia M Yeomans
- The Rudolf Peierls Centre for Theoretical Physics, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
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34
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Maryshev I, Morozov A, Goryachev AB, Marenduzzo D. Pattern formation in active model C with anchoring: bands, aster networks, and foams. SOFT MATTER 2020; 16:8775-8781. [PMID: 32857081 DOI: 10.1039/d0sm00927j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We study the dynamics of pattern formation in a minimal model for active mixtures made of microtubules and molecular motors. We monitor the evolution of the (conserved) microtubule density and of the (non-conserved) nematic order parameter, focusing on the effects of an "anchoring" term that provides a direct coupling between the preferred microtubule direction and their density gradient. The key control parameter is the ratio between activity and elasticity. When elasticity dominates, the interplay between activity and anchoring leads to formation of banded structures that can undergo additional bending, rotational or splaying instabilities. When activity dominates, the nature of anchoring instead gives rise to a range of active cellular solids, including aster-like networks, disordered foams and spindle-like patterns. We speculate that the introduced "active model C" with anchoring is a minimal model to describe pattern formation in a biomimetic analogue of the microtubule cytoskeleton.
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Affiliation(s)
- Ivan Maryshev
- SUPA, School of Physics and Astronomy, The University of Edinburgh, James Clerk Maxwell Building, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, UK. and Centre for Synthetic and Systems Biology, The University of Edinburgh, Institute of Cell Biology, Max Born Crescent, Edinburgh, EH9 3BF, UK.
| | - Alexander Morozov
- SUPA, School of Physics and Astronomy, The University of Edinburgh, James Clerk Maxwell Building, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, UK.
| | - Andrew B Goryachev
- Centre for Synthetic and Systems Biology, The University of Edinburgh, Institute of Cell Biology, Max Born Crescent, Edinburgh, EH9 3BF, UK.
| | - Davide Marenduzzo
- SUPA, School of Physics and Astronomy, The University of Edinburgh, James Clerk Maxwell Building, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, UK.
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35
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Carenza LN, Gonnella G, Lamura A, Marenduzzo D, Negro G, Tiribocchi A. Soft channel formation and symmetry breaking in exotic active emulsions. Sci Rep 2020; 10:15936. [PMID: 32985576 PMCID: PMC7522284 DOI: 10.1038/s41598-020-72742-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 08/22/2020] [Indexed: 11/09/2022] Open
Abstract
We use computer simulations to study the morphology and rheological properties of a bidimensional emulsion resulting from a mixture of a passive isotropic fluid and an active contractile polar gel, in the presence of a surfactant that favours the emulsification of the two phases. By varying the intensity of the contractile activity and of an externally imposed shear flow, we find three possible morphologies. For low shear rates, a simple lamellar state is obtained. For intermediate activity and shear rate, an asymmetric state emerges, which is characterized by shear and concentration banding at the polar/isotropic interface. A further increment in the active forcing leads to the self-assembly of a soft channel where an isotropic fluid flows between two layers of active material. We characterize the stability of this state by performing a dynamical test varying the intensity of the active forcing and shear rate. Finally, we address the rheological properties of the system by measuring the effective shear viscosity, finding that this increases as active forcing is increased-so that the fluid thickens with activity.
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Affiliation(s)
- L N Carenza
- Dipartimento di Fisica, Università degli Srudi di Bari and INFN, Sezione di Bari, Via Amendola 173, 70126, Bari, Italy
| | - G Gonnella
- Dipartimento di Fisica, Università degli Srudi di Bari and INFN, Sezione di Bari, Via Amendola 173, 70126, Bari, Italy
| | - A Lamura
- IAC - CNR, Via Amendola, 122/D, 70126, Bari, Italy
| | - D Marenduzzo
- SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh, EH9 3JZ, UK
| | - G Negro
- SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh, EH9 3JZ, UK.
| | - A Tiribocchi
- Center for Life Nano Science@La Sapienza, Istituto Italiano di Tecnologia, 00161, Rome, Italy.,IAC - CNR, Via dei Taurini 19, Rome, Italy
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36
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Petrelli I, Cugliandolo LF, Gonnella G, Suma A. Effective temperatures in inhomogeneous passive and active bidimensional Brownian particle systems. Phys Rev E 2020; 102:012609. [PMID: 32794963 DOI: 10.1103/physreve.102.012609] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 06/25/2020] [Indexed: 05/15/2023]
Abstract
We study the stationary dynamics of an active interacting Brownian particle system. We measure the violations of the fluctuation dissipation theorem, and the corresponding effective temperature, in a locally resolved way. Quite naturally, in the homogeneous phases the diffusive properties and effective temperature are also homogeneous. Instead, in the inhomogeneous phases (close to equilibrium and within the MIPS sector) the particles can be separated in two groups with different diffusion properties and effective temperatures. Notably, at fixed activity strength the effective temperatures in the two phases remain distinct and approximately constant within the MIPS region, with values corresponding to the ones of the whole system at the boundaries of this sector of the phase diagram. We complement the study of the globally averaged properties with the theoretical and numerical characterization of the fluctuation distributions of the single-particle diffusion, linear response, and effective temperature in the homogeneous and inhomogeneous phases. We also distinguish the behavior of the (time-delayed) effective temperature from the (instantaneous) kinetic temperature, showing that the former is independent of the friction coefficient.
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Affiliation(s)
- Isabella Petrelli
- Dipartimento di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari, I-70126, Italy
| | - Leticia F Cugliandolo
- Sorbonne Université, Laboratoire de Physique Théorique et Hautes Energies, CNRS UMR 7589, 4 Place Jussieu, 75252 Paris Cedex 05, France
- Institut Universitaire de France, 1 rue Descartes, 75005 Paris, France
| | - Giuseppe Gonnella
- Dipartimento di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari, I-70126, Italy
| | - Antonio Suma
- Dipartimento di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari, I-70126, Italy
- Institute for Computational Molecular Science, College of Science and Technology, Temple University, Philadelphia, Pennsylvania 19122, USA
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37
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Negro G, Carenza LN, Lamura A, Tiribocchi A, Gonnella G. Rheology of active polar emulsions: from linear to unidirectional and inviscid flow, and intermittent viscosity. SOFT MATTER 2019; 15:8251-8265. [PMID: 31553342 DOI: 10.1039/c9sm01288e] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The rheological behaviour of an emulsion made of an active polar component and an isotropic passive fluid is studied by lattice Boltzmann methods. Different flow regimes are found by varying the values of the shear rate and extensile activity (occurring, e.g., in microtubule-motor suspensions). By increasing the activity, a first transition occurs from the linear flow regime to spontaneous persistent unidirectional macro-scale flow, followed by another transition either to a (low shear) intermittent flow regime with the coexistence of states with positive, negative, and vanishing apparent viscosity, or to a (high shear) symmetric shear thinning regime. The different behaviours can be explained in terms of the dynamics of the polarization field close to the walls. A maximum entropy production principle selects the most likely states in the intermittent regime.
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Affiliation(s)
- G Negro
- Dipartimento di Fisica, Università degli Studi di Bari and INFN, Sezione di Bari, via Amendola 173, Bari, I-70126, Italy.
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