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Li K, Guo F, Zhou X, Wang X, He L, Zhang L. An attraction-repulsion transition of force on two asymmetric wedges induced by active particles. Sci Rep 2020; 10:11702. [PMID: 32678189 PMCID: PMC7367348 DOI: 10.1038/s41598-020-68677-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Accepted: 05/21/2020] [Indexed: 02/04/2023] Open
Abstract
Effective interaction between two asymmetric wedges immersed in a two-dimensional active bath is investigated by computer simulations. The attraction–repulsion transition of effective force between two asymmetric wedges is subjected to the relative position of two wedges, the wedge-to-wedge distance, the active particle density, as well as the apex angle of two wedges. By exchanging the position of the two asymmetric wedges in an active bath, firstly a simple attraction–repulsion transition of effective force occurs, completely different from passive Brownian particles. Secondly the transition of effective force is symmetric for the long-range distance between two asymmetric wedges, while it is asymmetric for the short-range case. Our investigations may provide new possibilities to govern the motion and assembly of microscopic objects by taking advantage of the self-driven behaviour of active particles.
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Affiliation(s)
- Ke Li
- Department of Physics, Zhejiang University, Hangzhou, 310027, Zhejiang, China
| | - Fuchen Guo
- Department of Physics, Zhejiang University, Hangzhou, 310027, Zhejiang, China
| | - Xiaolin Zhou
- Department of Physics, Zhejiang University, Hangzhou, 310027, Zhejiang, China
| | - Xianghong Wang
- Department of Physics, Wenzhou University, Wenzhou, 325035, Zhejiang, China
| | - Linli He
- Department of Physics, Wenzhou University, Wenzhou, 325035, Zhejiang, China.
| | - Linxi Zhang
- Department of Physics, Zhejiang University, Hangzhou, 310027, Zhejiang, China.
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Wang C, Jiang H. The inhibition of concentrated active baths. J Chem Phys 2020; 152:184907. [PMID: 32414266 DOI: 10.1063/5.0005313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Passive tracers in the active bath express fascinating behaviors. However, most studies are restricted to dilute active baths. Here, we use 2D simulation of suspensions consisting of active Brownian particles and a passive disk-shaped tracer to investigate tracers' diffusive behaviors in a wide range of volume fractions. Due to the competition between the thermal noise and collisions with active particles, tracers express a first transition from the normal diffusion to the superdiffusion at a short time scale and recur to normal diffusion at a long time scale. At a low volume fraction, infrequent active collisions retard the first transition of smaller tracers. At a high volume fraction, active particles with high activity aggregating around tracers induce a bimodal probability distribution function of tracer displacements during superdiffusion. Considering the enhancement of diffusion, the non-dimensional enhanced diffusivity increases asymptotically with the Peclet number. The asymptotic line gives an upper limit of non-dimensional enhanced diffusivity of tracers. Cases with lower enhanced diffusion have a high volume fraction and a low active velocity that indicates the inhibition of concentrated active baths. With the high negentropic work of these cases, the inhibition is explained as the change of the configuration of active baths for introducing tracers.
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Affiliation(s)
- Chen Wang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Hefei National Laboratory for Physical Science at the Microscale, CAS Center for Excellence in Complex System Mechanics, Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Hongyuan Jiang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Hefei National Laboratory for Physical Science at the Microscale, CAS Center for Excellence in Complex System Mechanics, Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230026, China
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Wang C, Jiang H. Different-shaped micro-objects driven by active particle aggregations. SOFT MATTER 2020; 16:4422-4430. [PMID: 32364209 DOI: 10.1039/d0sm00160k] [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
The dynamics of passive micro-objects in an active bath has been receiving much attention. However, the influence of the shapes of micro-objects remains unclear. Here, we use 2D simulation to investigate the interaction between active Brownian particles and different-shaped passive micro-objects. We show that active particles accumulate around micro-objects and self-assemble into living aggregations at a high active velocity and high volume fraction. The shapes of micro-objects affect the distributions of the aggregations. In turn, the different distribution of aggregations influences the motion of micro-objects and induces abnormal diffusive behaviors. We further demonstrate that polar distributed aggregations at a high active velocity and the inhibition of the active bath at a low active velocity induce the counterintuitive anisotropic enhanced diffusion of rods, and the steric interaction between active particles induces the reverse translation-rotation coupled diffusion of chevrons.
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Affiliation(s)
- Chen Wang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Hefei National Laboratory for Physical Science at the Microscale, CAS Center for Excellence in Complex System Mechanics, Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230026, China.
| | - Hongyuan Jiang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Hefei National Laboratory for Physical Science at the Microscale, CAS Center for Excellence in Complex System Mechanics, Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230026, China.
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Hoell C, Löwen H, Menzel AM. Multi-species dynamical density functional theory for microswimmers: Derivation, orientational ordering, trapping potentials, and shear cells. J Chem Phys 2019. [DOI: 10.1063/1.5099554] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Christian Hoell
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany
| | - Hartmut Löwen
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany
| | - Andreas M. Menzel
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany
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Hua Y, Li K, Zhou X, He L, Zhang L. An attraction-repulsion transition of force on wedges induced by active particles. SOFT MATTER 2018; 14:5205-5212. [PMID: 29888771 DOI: 10.1039/c8sm00249e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Effective forces between two micro-wedges immersed in an active bath are investigated using Brownian dynamics simulations. Two anti-parallel and parallel wedge-like obstacles are considered respectively, and the effective forces between two wedges rely on the wedge-to-wedge distance, the apex angle of the wedge, as well as the particle density and aspect ratio. For two anti-parallel wedges, a transition from repulsion to attraction occurs by varying the apex angle, which is also sensitive to the particle density and aspect ratio. The optimal apex angle θr* (or θa*) and particle density ρ* are characterized by the saturated trapping of active particles inside a wedge. For two parallel wedges, the effective force also experiences a transition from repulsion to attraction as the wedge-to-wedge distance increases. These results originate from the collective trapping effect which is driven by the many-body dynamics of self-propelled particles in the confinement (near the boundary) of obstacles. Our results can provide insight into controlling the motion and assembly of microscopic objects through the suspension of active particles.
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Affiliation(s)
- Yunfeng Hua
- Department of Physics, Zhejiang University, Zhejiang, 310027, China.
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Affiliation(s)
| | - Chantal Valeriani
- Departamento de Física Aplicada I, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Angelo Cacciuto
- Department of Chemistry, Columbia University, New York, NY 10027, USA
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Mallory SA, Cacciuto A. Activity-assisted self-assembly of colloidal particles. Phys Rev E 2016; 94:022607. [PMID: 27627360 DOI: 10.1103/physreve.94.022607] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Indexed: 06/06/2023]
Abstract
We outline a basic strategy of how self-propulsion can be used to improve the yield of a typical colloidal self-assembly process. The success of this approach is predicated on the thoughtful design of the colloidal building block as well as how self-propulsion is endowed to the particle. As long as a set of criteria are satisfied, it is possible to significantly increase the rate of self-assembly, and greatly expand the window in parameter space where self-assembly can occur. In addition, we show that by tuning the relative on-off time of the self-propelling force it is possible to modulate the effective speed of the colloids allowing for further optimization of the self-assembly process.
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Affiliation(s)
- S A Mallory
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, USA
| | - A Cacciuto
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, USA
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Kaiser A, Babel S, ten Hagen B, von Ferber C, Löwen H. How does a flexible chain of active particles swell? J Chem Phys 2016; 142:124905. [PMID: 25833607 DOI: 10.1063/1.4916134] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We study the swelling of a flexible linear chain composed of active particles by analytical theory and computer simulation. Three different situations are considered: a free chain, a chain confined to an external harmonic trap, and a chain dragged at one end. First, we consider an ideal chain with harmonic springs and no excluded volume between the monomers. The Rouse model of polymers is generalized to the case of self-propelled monomers and solved analytically. The swelling, as characterized by the spatial extension of the chain, scales with the monomer number defining a Flory exponent ν which is ν = 1/2, 0, 1 in the three different situations. As a result, we find that activity does not change the Flory exponent but affects the prefactor of the scaling law. This can be quantitatively understood by mapping the system onto an equilibrium chain with a higher effective temperature such that the chain swells under an increase of the self-propulsion strength. We then use computer simulations to study the effect of self-avoidance on active polymer swelling. In the three different situations, the Flory exponent is now ν = 3/4, 1/4, 1 and again unchanged under self-propulsion. However, the chain extension behaves non-monotonic in the self-propulsion strength.
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Affiliation(s)
- Andreas Kaiser
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Sonja Babel
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Borge ten Hagen
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Christian von Ferber
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Hartmut Löwen
- Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
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