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Boudet JF, Lintuvuori J, Lacouture C, Barois T, Deblais A, Xie K, Cassagnere S, Tregon B, Brückner DB, Baret JC, Kellay H. From collections of independent, mindless robots to flexible, mobile, and directional superstructures. Sci Robot 2021; 6:6/56/eabd0272. [PMID: 34290101 DOI: 10.1126/scirobotics.abd0272] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 06/23/2021] [Indexed: 12/15/2022]
Abstract
A swarm of simple active particles confined in a flexible scaffold is a promising system to make mobile and deformable superstructures. These soft structures can perform tasks that are difficult to carry out for monolithic robots because they can infiltrate narrow spaces, smaller than their size, and move around obstacles. To achieve such tasks, the origin of the forces the superstructures develop, how they can be guided, and the effects of external environment, especially geometry and the presence of obstacles, need to be understood. Here, we report measurements of the forces developed by such superstructures, enclosing a number of mindless active rod-like robots, as well as the forces exerted by these structures to achieve a simple function, crossing a constriction. We relate these forces to the self-organization of the individual entities. Furthermore, and based on a physical understanding of what controls the mobility of these superstructures and the role of geometry in such a process, we devise a simple strategy where the environment can be designed to bias the mobility of the superstructure, giving rise to directional motion. Simple tasks-such as pulling a load, moving through an obstacle course, or cleaning up an arena-are demonstrated. Rudimentary control of the superstructures using light is also proposed. The results are of relevance to the making of robust flexible superstructures with nontrivial space exploration properties out of a swarm of simpler and cheaper robots.
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Affiliation(s)
- J F Boudet
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33400 Talence, France
| | - J Lintuvuori
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33400 Talence, France
| | - C Lacouture
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33400 Talence, France
| | - T Barois
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33400 Talence, France
| | - A Deblais
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, 1098XH Amsterdam, Netherlands
| | - K Xie
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33400 Talence, France
| | - S Cassagnere
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33400 Talence, France
| | - B Tregon
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33400 Talence, France
| | - D B Brückner
- Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience, Ludwig-Maximilian-University Munich, Theresienstr. 37, D-80333 Munich, Germany
| | - J C Baret
- Univ. Bordeaux, CNRS, CRPP-UMR5031, 33600 Pessac, France.,Institut Universitaire de France, 75005 Paris, France
| | - H Kellay
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33400 Talence, France. .,Institut Universitaire de France, 75005 Paris, France
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Bittermann MR, Deblais A, Lépinay S, Bonn D, Shahidzadeh N. Author Correction: Deposits from evaporating emulsion drops. Sci Rep 2020; 10:17133. [PMID: 33028953 PMCID: PMC7542458 DOI: 10.1038/s41598-020-74408-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Deblais A, Maggs AC, Bonn D, Woutersen S. Phase Separation by Entanglement of Active Polymerlike Worms. Phys Rev Lett 2020; 124:208006. [PMID: 32501051 DOI: 10.1103/physrevlett.124.208006] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 03/24/2020] [Accepted: 05/06/2020] [Indexed: 06/11/2023]
Abstract
We investigate the aggregation and phase separation of thin, living T. tubifex worms that behave as active polymers. Randomly dispersed active worms spontaneously aggregate to form compact, highly entangled blobs, a process similar to polymer phase separation, and for which we observe power-law growth kinetics. We find that the phase separation of active polymerlike worms does not occur through Ostwald ripening, but through active motion and coalescence of the phase domains. Interestingly, the growth mechanism differs from conventional growth by droplet coalescence: the diffusion constant characterizing the random motion of a worm blob is independent of its size, a phenomenon that can be explained from the fact that the active random motion arises from the worms at the surface of the blob. This leads to a fundamentally different phase-separation mechanism that may be unique to active polymers.
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Affiliation(s)
- A Deblais
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, 1098XH Amsterdam, The Netherlands
| | - A C Maggs
- UMR Gulliver 7083 CNRS, ESPCI, PSL Research University, 10 rue Vauquelin, 75005 Paris, France
| | - D Bonn
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, 1098XH Amsterdam, The Netherlands
| | - S Woutersen
- Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands
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Deblais A, Woutersen S, Bonn D. Rheology of Entangled Active Polymer-Like T. Tubifex Worms. Phys Rev Lett 2020; 124:188002. [PMID: 32441969 DOI: 10.1103/physrevlett.124.188002] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 03/18/2020] [Accepted: 04/13/2020] [Indexed: 06/11/2023]
Abstract
We experimentally study the rheology of long, slender, and entangled living worms (Tubifex Tubifex). Their level of activity can be controlled by changing the temperature or by adding small amounts of alcohol to make the worms temporarily inactive. Performing classical rheology experiments on this entangled polymer-like system, we find that the rheology is qualitatively similar to that of usual polymers, but, quantitatively, (i) shear thinning is reduced by activity, (ii) the characteristic shear rate for the onset of shear-thinning is given by the time scale of the activity, and (iii) the low shear viscosity as a function of concentration shows a very different scaling from that of regular polymers. Our study paves the way towards a new experimental research field of active "polymer-like worms."
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Affiliation(s)
- A Deblais
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, 1098XH Amsterdam, The Netherlands
| | - S Woutersen
- Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands
| | - D Bonn
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, 1098XH Amsterdam, The Netherlands
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Deblais A, Herrada MA, Hauner I, Velikov KP, van Roon T, Kellay H, Eggers J, Bonn D. Viscous Effects on Inertial Drop Formation. Phys Rev Lett 2018; 121:254501. [PMID: 30608844 DOI: 10.1103/physrevlett.121.254501] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 09/10/2018] [Indexed: 06/09/2023]
Abstract
The breakup of low-viscosity droplets like water is a ubiquitous and rich phenomenon. Theory predicts that in the inviscid limit one observes a finite-time singularity, giving rise to a universal power law, with a prefactor that is universal for a given density and surface tension. This universality has been proposed as a powerful tool to determine the dynamic surface tension at short time scales. We combine high-resolution experiments and simulations to show that this universality is unobservable in practice: in contrast to previous studies, we show that fluid and system parameters do play a role; notably a small amount of viscosity is sufficient to alter the breakup dynamics significantly.
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Affiliation(s)
- A Deblais
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, 1098XH Amsterdam, Netherlands
| | - M A Herrada
- Depto. de Mecánica de Fluidos e Ingeniería Aeroespacial, Universidad de Sevilla, E-41092 Sevilla, Spain
| | - I Hauner
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, 1098XH Amsterdam, Netherlands
| | - K P Velikov
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, 1098XH Amsterdam, Netherlands
- Unilever R&D Vlaardingen, Olivier van Noortlaan 120, 3133 AT Vlaardingen, Netherlands
| | - T van Roon
- Technology Centre, University of Amsterdam, 1098XH Amsterdam, Netherlands
| | - H Kellay
- Laboratoire Ondes et Matiere d'Aquitaine, UMR 5798 CNRS-U. Bx, Universite de Bordeaux, 351 cours de la Liberation 33405, Talence, France
| | - J Eggers
- School of Mathematics, University of Bristol, University Walk, Bristol BS8 1 TW, United Kingdom
| | - D Bonn
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, 1098XH Amsterdam, Netherlands
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Abstract
Pearling instabilities of slender viscoelastic threads have received much attention, but remain incompletely understood. We study the instabilities in polymer solutions subject to uniaxial elongational flow. Two distinctly different instabilites are observed: beads on a string and blistering. The beads-on-a-string structure arises from a capillary instability whereas the blistering instability has a different origin: it is due to a coupling between stress and polymer concentration. By varying the temperature to change the solution properties we elucidate the interplay between flow and phase separation.
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Affiliation(s)
- A Deblais
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, 1098XH Amsterdam, Netherlands
| | - K P Velikov
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, 1098XH Amsterdam, Netherlands
- Unilever R&D Vlaardingen, Olivier van Noortlaan 120, 3133 AT Vlaardingen, Netherlands
| | - D Bonn
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, 1098XH Amsterdam, Netherlands
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Deblais A, Barois T, Guerin T, Delville PH, Vaudaine R, Lintuvuori JS, Boudet JF, Baret JC, Kellay H. Boundaries Control Collective Dynamics of Inertial Self-Propelled Robots. Phys Rev Lett 2018; 120:188002. [PMID: 29775342 DOI: 10.1103/physrevlett.120.188002] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 02/13/2018] [Indexed: 06/08/2023]
Abstract
Simple ingredients, such as well-defined interactions and couplings for the velocity and orientation of self-propelled objects, are sufficient to produce complex collective behavior in assemblies of such entities. Here, we use assemblies of rodlike robots made motile through self-vibration. When confined in circular arenas, dilute assemblies of these rods act as a gas. Increasing the surface fraction leads to a collective behavior near the boundaries: polar clusters emerge while, in the bulk, gaslike behavior is retained. The coexistence between a gas and surface clusters is a direct consequence of inertial effects as shown by our simulations. A theoretical model, based on surface mediated transport accounts for this coexistence and illustrates the exact role of the boundaries. Our study paves the way towards the control of collective behavior: By using deformable but free to move arenas, we demonstrate that the surface induced clusters can lead to directed motion, while the topology of the surface states can be controlled by biasing the motility of the particles.
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Affiliation(s)
- A Deblais
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33405 Talence, France
| | - T Barois
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33405 Talence, France
| | - T Guerin
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33405 Talence, France
| | - P H Delville
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33405 Talence, France
| | - R Vaudaine
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33405 Talence, France
| | - J S Lintuvuori
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33405 Talence, France
| | - J F Boudet
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33405 Talence, France
| | - J C Baret
- CNRS, Univ. Bordeaux, CRPP, UPR 8641, 115 Avenue Schweitzer, 33600 Pessac, France
| | - H Kellay
- Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33405 Talence, France
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Khodaparast S, Atasi O, Deblais A, Scheid B, Stone HA. Dewetting of Thin Liquid Films Surrounding Air Bubbles in Microchannels. Langmuir 2018; 34:1363-1370. [PMID: 29239613 DOI: 10.1021/acs.langmuir.7b03839] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
As an air bubble translates in a microchannel, a thin film of liquid is formed on the bounding walls. In a microchannel with a rectangular cross-section, the liquid in the film leaks toward the low-pressure corners of the geometry, which leads to the appearance of local minima in the film thickness in the cross-sectional plane. In such a configuration, theory suggests that the minimum film thickness scales with Ca and Ca4/3 depending on the distance from the nose of the bubble, where Ca = μUb/γ is the flow capillary number based on the bubble velocity Ub, liquid viscosity μ, and surface tension γ, and Ca ≪ 1. We show that the film of a partially wetting liquid dewets on the channel wall at the sites of the local minima in the film thickness as it acquires thicknesses around and below 100 nm. Our experiments show that the distance Lw between the nose of the bubble and the initial dewetting location is a function of Ca and surface wettability. For channels of different wettability, Lw always scales proportional to Caα, where 1.7 < α < 2 for the range of 10-5 < Ca < 10-2. Moreover, Lw increases up to 10 times by enhancing the wettability of the surface at a given Ca. Our present measurements of Lw provide a design constraint on the lengths of bubbles to maintain a liquid wet channel without dry patches on the wall.
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Affiliation(s)
- S Khodaparast
- Department of Mechanical and Aerospace Engineering, Princeton University , Princeton, New Jersey 08544, United States
- Department of Chemical Engineering, Imperial College London , London SW7 2AZ, United Kingdom
| | - O Atasi
- Department of Mechanical and Aerospace Engineering, Princeton University , Princeton, New Jersey 08544, United States
- TIPs (Transfers, Interfaces and Processes), Université Libre de Bruxelles , Brussels 1050, Belgium
| | - A Deblais
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam , 1098XH Amsterdam, The Netherlands
| | - B Scheid
- TIPs (Transfers, Interfaces and Processes), Université Libre de Bruxelles , Brussels 1050, Belgium
| | - H A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University , Princeton, New Jersey 08544, United States
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Abstract
Coating surfaces with different fluids is prone to instability producing inhomogeneous films and patterns. The contact line between the coating fluid and the surface to be coated is host to different instabilities, limiting the use of a variety of coating techniques. Here we take advantage of the instability of a receding contact line towards cusp and droplet formation to produce linear patterns of variable spacings. We stabilize the instability of the cusps towards droplet formation by using polymer solutions that inhibit this secondary instability and give rise to long slender cylindrical filaments. We vary the speed of deposition to change the spacing between these filaments. The combination of the two gives rise to linear patterns into which different colloidal particles can be embedded, long DNA molecules can be stretched and particles filtered by size. The technique is therefore suitable to prepare anisotropic structures with variable properties.
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Affiliation(s)
- A. Deblais
- LOMA, Laboratoire Ondes et Matiere d'Aquitaine (UMR 5798), Universite de Bordeaux—CNRS, 33405 Talence, France
| | - R. Harich
- LOMA, Laboratoire Ondes et Matiere d'Aquitaine (UMR 5798), Universite de Bordeaux—CNRS, 33405 Talence, France
| | - A. Colin
- ESPCI, CNRS, SIMM UMR 7615, 11 rue Vauquelin, 75005 Paris, France
| | - H. Kellay
- LOMA, Laboratoire Ondes et Matiere d'Aquitaine (UMR 5798), Universite de Bordeaux—CNRS, 33405 Talence, France
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Deblais A, Harich R, Bonn D, Colin A, Kellay H. Spreading of an Oil-in-Water Emulsion on a Glass Plate: Phase Inversion and Pattern Formation. Langmuir 2015; 31:5971-5981. [PMID: 26000801 DOI: 10.1021/la504639q] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Rigid blade coating of glass plates by oil-in-water emulsions stabilized by surfactants is studied. Complete surface coverage is obtained only for speeds exceeding a threshold velocity dependent on the height between the blade end and the surface. Below this threshold, the emulsion can be inverted in the vicinity of the blade. The inversion dynamics of the oil-in-water emulsion and the deposition patterns induced by this phase inversion are studied using a microscope mounted set up. We show that these dynamics are universal for different volume fractions and deposition velocities. This inversion as well as the destabilization of the emulsion film deposited at high speeds gives rise to different patterns on the glass surface. These patterns are discussed in terms of the emulsion characteristics as well as the deposition velocity.
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Affiliation(s)
- A Deblais
- †Laboratoire Ondes et Matière d'Aquitaine, UMR 5798 CNRS-U. Bx, Université de Bordeaux, 351 cours de la Libération 33405, Talence, France
| | - R Harich
- †Laboratoire Ondes et Matière d'Aquitaine, UMR 5798 CNRS-U. Bx, Université de Bordeaux, 351 cours de la Libération 33405, Talence, France
| | - D Bonn
- ‡van der Waals-Zeeman Institute, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, Netherlands
| | - A Colin
- §Centre de Recherche Paul Pascal, CNRS UPR 8641, Université de Bordeaux, 115 av. Schweitzer, F-33600 Pessac, France
| | - H Kellay
- †Laboratoire Ondes et Matière d'Aquitaine, UMR 5798 CNRS-U. Bx, Université de Bordeaux, 351 cours de la Libération 33405, Talence, France
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