1
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Baumgartner DA, Shiri S, Sinha S, Karpitschka S, Cira NJ. Marangoni spreading and contracting three-component droplets on completely wetting surfaces. Proc Natl Acad Sci U S A 2022; 119:e2120432119. [PMID: 35507868 PMCID: PMC9171644 DOI: 10.1073/pnas.2120432119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 03/22/2022] [Indexed: 11/24/2022] Open
Abstract
SignificanceThe shape and dynamics of small sessile droplets are dictated by capillary forces. For liquid mixtures, evaporation adds spatio-temporal modulation to these forces that can either enhance or inhibit droplet spreading, depending on the direction of the resulting Marangoni flow. This work experimentally and numerically demonstrates the coexistence of two antagonistic Marangoni flows in a ternary mixture. Played against each other, they can choreograph a boomerang-like wetting motion: Droplets initially rapidly spread, then contract into a compact cap shape. While such a behavior has been impossible in wetting scenarios of simple liquids, it enables spread-retract-remove surface processing with the addition of a single small liquid volume, demonstrated here in a surface-cleaning experiment.
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Affiliation(s)
- Dieter A. Baumgartner
- Rowland Institute, Harvard University, Cambridge, MA 02142
- Environmental Microfluidics Group, Institute of Environmental Engineering, Department of Civil, Environmental, and Geomatic Engineering, ETH Zürich, 8093 Zürich, Switzerland
| | - Samira Shiri
- Rowland Institute, Harvard University, Cambridge, MA 02142
- Department of Biomedical Engineering, Cornell University, Ithaca, NY 14850
| | | | - Stefan Karpitschka
- Max Planck Institute for Dynamics and Self-Organization, 37077 Göttingen, Germany
| | - Nate J. Cira
- Rowland Institute, Harvard University, Cambridge, MA 02142
- Department of Biomedical Engineering, Cornell University, Ithaca, NY 14850
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2
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Staniscia F, Guzman HV, Kanduč M. Tuning Contact Angles of Aqueous Droplets on Hydrophilic and Hydrophobic Surfaces by Surfactants. J Phys Chem B 2022; 126:3374-3384. [PMID: 35468298 PMCID: PMC9082615 DOI: 10.1021/acs.jpcb.2c01599] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Adsorption of small
amphiphilic molecules occurs in various biological
and technological processes, sometimes desired while other times unwanted
(e.g., contamination). Surface-active molecules preferentially bind
to interfaces and affect their wetting properties. We use molecular
dynamics simulations to study the adsorption of short-chained alcohols
(simple surfactants) to the water–vapor interface and solid
surfaces of various polarities. With a theoretical analysis, we derive
an equation for the adsorption coefficient, which scales exponentially
with the molecular surface area and the surface wetting coefficient
and is in good agreement with the simulation results. We apply the
outcomes to aqueous sessile droplets containing surfactants, where
the competition of surfactant adsorptions to both interfaces alters
the contact angle in a nontrivial way. The influence of surfactants
is the strongest on very hydrophilic and hydrophobic surfaces, whereas
droplets on moderately hydrophilic surfaces are less affected.
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Affiliation(s)
- Fabio Staniscia
- Department of Theoretical Physics, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia
| | - Horacio V Guzman
- Department of Theoretical Physics, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia
| | - Matej Kanduč
- Department of Theoretical Physics, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia
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3
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Korolev I, Aliev TA, Orlova T, Ulasevich SA, Nosonovsky M, Skorb EV. When Bubbles Are Not Spherical: Artificial Intelligence Analysis of Ultrasonic Cavitation Bubbles in Solutions of Varying Concentrations. J Phys Chem B 2022; 126:3161-3169. [PMID: 35435685 DOI: 10.1021/acs.jpcb.2c00948] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Ultrasonic irradiation of liquids, such as water-alcohol solutions, results in cavitation or the formation of small bubbles. Cavitation bubbles are generated in real solutions without the use of optical traps making our system as close to real conditions as possible. Under the action of the ultrasound, bubbles can grow, oscillate, and eventually collapse or decompose. We apply the mathematical method of separation of motions to interpret the acoustic effect on the bubbles. While in most situations, the spherical shape of a bubble is the most energetically profitable as it minimizes the surface energy, when the acoustic frequency is in resonance with the natural frequency of the bubble, shapes with the dihedral symmetry emerge. Some of these resonance shapes turn unstable, so the bubble decomposes. It turns out that bubbles in the solutions of different concentrations (with different surface energies and densities) attain different evolution paths. While it is difficult to obtain a deterministic description of how the solution concentration affects bubble dynamics, it is possible to separate images with different concentrations by applying the artificial neural network (ANN) algorithm. An ANN was trained to detect the concentration of alcohol in a water solution based on the bubble images. This indicates that artificial intelligence (AI) methods can complement deterministic analysis in nonequilibrium, near-unstable situations.
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Affiliation(s)
- Ilya Korolev
- Infochemistry Scientific Center, ITMO University, 9 Lomonosov St., St. Petersburg 191002, Russia
| | - Timur A Aliev
- Infochemistry Scientific Center, ITMO University, 9 Lomonosov St., St. Petersburg 191002, Russia
| | - Tetiana Orlova
- Infochemistry Scientific Center, ITMO University, 9 Lomonosov St., St. Petersburg 191002, Russia
| | - Sviatlana A Ulasevich
- Infochemistry Scientific Center, ITMO University, 9 Lomonosov St., St. Petersburg 191002, Russia
| | - Michael Nosonovsky
- Infochemistry Scientific Center, ITMO University, 9 Lomonosov St., St. Petersburg 191002, Russia
| | - Ekaterina V Skorb
- Infochemistry Scientific Center, ITMO University, 9 Lomonosov St., St. Petersburg 191002, Russia
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4
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Bala M, Singh V. Self-Moving blooming drops of dimethyl sulfoxide containing benzyne intermediate for solutal transport. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.118514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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5
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Batishcheva K, Kuznetsov G, Orlova E, Vympina Y. Evaporation of colloidal droplets from aluminum–magnesium alloy surfaces after laser-texturing and mechanical processing. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.127301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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6
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Tadmor R. Open Problems in Wetting Phenomena: Pinning Retention Forces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:6357-6372. [PMID: 34008988 DOI: 10.1021/acs.langmuir.0c02768] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We review existing explanations for drop pinning and the origin of the force required to initiate the sliding of a drop on a solid surface (depinning). Theories that describe these phenomena include de Gennes', Marmur's, Furmidge's, the related Furmidge-Extrand's, and Tadmor's theory. These theories are all well cited but generally do not address each other, and usually papers that cite one of them ignore the others. Here, we discuss the advantages and disadvantages of these theories and their applicability to different experimental systems. Thus, we link different experimental systems to the theories that describe them best. We describe the force laws that can be deduced should these theories be united and the major open problems that remain. We describe a physical meaning that can be extracted from retention force measurements, specifically, the interfacial modulus that describes the tendency of a solid to conform to the liquid. This has implications for various wetting phenomena such as adhesion robustness, drug penetration into biological tissues, and solid robustness/resilience versus solid degradation over time as a result of its contact with a liquid.
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Affiliation(s)
- Rafael Tadmor
- Department of Mechanical Engineering, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105, Israel
- Dan F. Smith Department of Chemical Engineering, Lamar University, Beaumont Texas 77710, United States
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7
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Bera B, Backus EHG, Carrier O, Bonn M, Shahidzadeh N, Bonn D. Antisurfactant (Autophobic) Behavior of Superspreader Surfactant Solutions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:6243-6247. [PMID: 33983746 PMCID: PMC8280720 DOI: 10.1021/acs.langmuir.1c00475] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/19/2021] [Indexed: 06/12/2023]
Abstract
Surfactants are often added to water to increase the wetting of hydrophobic surfaces. We previously showed that most surfactant solutions behave identically to simple liquids with the same surface tension, indicating that the surfactants do not change the wettability of the solid surface itself. Here, we show that the superspreading surfactant Silwet results in a systematically higher contact angle on a hydrophobic surface than other surfactant solutions of comparable liquid-vapor surface tension. We also experimentally observe this "antisurfactant" behavior for CTAB on hydrophilic substrates. Supported by sum-frequency generation spectroscopy results, we suggest that this effect is due to charge-binding of the surfactant with the substrate.
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Affiliation(s)
- Bijoy Bera
- Institute
of Physics, Science Park 904, 1098XH Amsterdam, The Netherlands
| | - Ellen H. G. Backus
- Institut
für Physikalische Chemie, Währinger Straße 42, 1090 Wien, Austria
- Max
Planck Institute for Polymer Research, Ackermannweg 10, D-35128 Mainz, Germany
| | - Odile Carrier
- Institute
of Physics, Science Park 904, 1098XH Amsterdam, The Netherlands
| | - Mischa Bonn
- Max
Planck Institute for Polymer Research, Ackermannweg 10, D-35128 Mainz, Germany
| | | | - Daniel Bonn
- Institute
of Physics, Science Park 904, 1098XH Amsterdam, The Netherlands
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8
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Wang Z, Wang X, Miao Q, Gao F, Zhao YP. Spontaneous Motion and Rotation of Acid Droplets on the Surface of a Liquid Metal. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:4370-4379. [PMID: 33792321 DOI: 10.1021/acs.langmuir.1c00455] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Self-propulsion of droplets is of great significance in many fields. The spontaneous horizontal motion and self-jumping of droplets have been well realized in various ways. However, there is still a lack of an effective method to enable a droplet to rotate spontaneously and steadily. In this paper, by employing an acid droplet and a liquid metal, the spontaneous and steady rotation of droplets is achieved. For an acid droplet, it may spontaneously move when it is deposited on the surface of the liquid metal. By adjusting experimental parameters to the proper range, the self-rotation of droplet happens. This phenomenon originates from the fluctuation of the droplet boundary and the collective movement of bubbles that are generated by the chemical reactions between the acid droplet and liquid metal. This rotation has a simpler implementation method and more steady rotation state. Its angular velocity is much higher than that driven by other mechanisms. Moreover, the movements of acid droplets on the liquid metal are classified according to experimental conditions. The internal flow fields, the movements and distribution of bubbles, and the fluctuation of the droplet boundary are also explored and discussed. The theoretical model describing the rotational droplet is given. Our work may deepen the understanding of the physical system transition affected by chemical reactions and provide a new way for the design of potential applications, e.g., micro- and nanodevices.
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Affiliation(s)
- Zhanlong Wang
- State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
- School of Engineering Science, University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China
| | - Xiaohe Wang
- State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
- School of Engineering Science, University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China
| | - Qing Miao
- State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
- School of Engineering Science, University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China
| | - Feifei Gao
- State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
- School of Engineering Science, University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China
| | - Ya-Pu Zhao
- State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
- School of Engineering Science, University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China
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9
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Hack MA, Kwieciński W, Ramírez-Soto O, Segers T, Karpitschka S, Kooij ES, Snoeijer JH. Wetting of Two-Component Drops: Marangoni Contraction Versus Autophobing. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:3605-3611. [PMID: 33734702 PMCID: PMC8015233 DOI: 10.1021/acs.langmuir.0c03571] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/15/2021] [Indexed: 06/12/2023]
Abstract
The wetting properties of multicomponent liquids are crucial to numerous industrial applications. The mechanisms that determine the contact angles for such liquids remain poorly understood, with many intricacies arising due to complex physical phenomena, for example, due to the presence of surfactants. Here, we consider two-component drops that consist of mixtures of vicinal alkanediols and water. These diols behave surfactant-like in water. However, the contact angles of such mixtures on solid substrates are surprisingly large. We experimentally reveal that the contact angle is determined by two separate mechanisms of completely different nature, namely, Marangoni contraction (hydrodynamic) and autophobing (molecular). The competition between these effects can even inhibit Marangoni contraction, highlighting the importance of molecular structures in physico-chemical hydrodynamics.
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Affiliation(s)
- Michiel A. Hack
- Physics
of Fluids Group, Max Planck Center for Complex Fluid Dynamics, Faculty
of Science and Technology, University of
Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Wojciech Kwieciński
- Physics
of Interfaces and Nanomaterials Group, MESA+ Institute for Nanotechnology, University of Twente,
P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Olinka Ramírez-Soto
- Max
Planck Institute for Dynamics and Self-Organization, Am Faßberg 17, 37077 Göttingen, Germany
| | - Tim Segers
- Physics
of Fluids Group, Max Planck Center for Complex Fluid Dynamics, Faculty
of Science and Technology, University of
Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Stefan Karpitschka
- Max
Planck Institute for Dynamics and Self-Organization, Am Faßberg 17, 37077 Göttingen, Germany
| | - E. Stefan Kooij
- Physics
of Interfaces and Nanomaterials Group, MESA+ Institute for Nanotechnology, University of Twente,
P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Jacco H. Snoeijer
- Physics
of Fluids Group, Max Planck Center for Complex Fluid Dynamics, Faculty
of Science and Technology, University of
Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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10
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Kovalchuk NM, Simmons MJ. Surfactant-mediated wetting and spreading: Recent advances and applications. Curr Opin Colloid Interface Sci 2021. [DOI: 10.1016/j.cocis.2020.07.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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11
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Tadmor R, Multanen V, Stern Y, Yakir YB. Drops retracting while forming a rim. J Colloid Interface Sci 2021; 581:496-503. [DOI: 10.1016/j.jcis.2020.07.109] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 07/21/2020] [Accepted: 07/22/2020] [Indexed: 01/31/2023]
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12
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Fedorets AA, Shcherbakov DV, Dombrovsky LA, Bormashenko E, Nosonovsky M. Impact of Surfactants on the Formation and Properties of Droplet Clusters. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:11154-11160. [PMID: 32872782 DOI: 10.1021/acs.langmuir.0c02241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A levitating cluster of condensed microdroplets can form over the heated area of a water layer. The thermocapillary (TC) flow at the surface of the water layer combined with the convective flow in the layer often prevents a cluster's stability due to disturbances that it creates in the gas flow over the water surface. The TC flow can be suppressed by introducing small amounts of surfactants into the water layer. We conduct a systematic study of the effect of a surfactant on the cluster. We show experimentally that the introduction of the surfactant sodium laureth sulfate with concentrations of 0.05-0.5 g/L can suppress the TC convection. It is shown that the amount of surfactant does not affect the condensational growth of droplets and the structure of the cluster. In the absence of the surfactant, a ring-shaped cluster is formed, which is reported in this paper for the first time.
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Affiliation(s)
- Alexander A Fedorets
- X-BIO Institute, University of Tyumen, 6 Volodarskogo Street, Tyumen 625003, Russia
| | - Dmitry V Shcherbakov
- X-BIO Institute, University of Tyumen, 6 Volodarskogo Street, Tyumen 625003, Russia
| | - Leonid A Dombrovsky
- X-BIO Institute, University of Tyumen, 6 Volodarskogo Street, Tyumen 625003, Russia
- Joint Institute for High Temperatures, 17A Krasnokazarmennaya Street, Moscow 111116, Russia
| | - Edward Bormashenko
- Department of Chemical Engineering, Biotechnology and Materials, Engineering Science Faculty, Ariel University, Ariel 40700, Israel
| | - Michael Nosonovsky
- X-BIO Institute, University of Tyumen, 6 Volodarskogo Street, Tyumen 625003, Russia
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, Cramer Street, Milwaukee, Wisconsin 53211, United States
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13
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Abstract
Spiral thermal surface waves arising from self-propulsion of the camphor-driven objects are reported. Spiral thermal waves were registered for dissolution and evaporation-guided self-propulsion. Soluto-capillarity is accompanied by thermo-capillarity under self-propulsion of camphor boats. The jump in the surface tension due to the soluto-capillarity is much larger than that due to the thermo-capillarity. The spiral patterns inherent for the surface thermal waves are imposed by the self-rotational motion of camphor grains. The observed thermal effect is related to the adsorption of camphor molecules at the water/vapor interface. The observed spirals are shaped as Archimedean ones.
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14
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Galy PE, Rudiuk S, Morel M, Baigl D. Self-Propelled Water Drops on Bare Glass Substrates in Air: Fast, Controllable, and Easy Transport Powered by Surfactants. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:6916-6923. [PMID: 32074453 DOI: 10.1021/acs.langmuir.9b03727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Self-propelled drops are capable of motion without external intervention. As such, they constitute attractive entities for fundamental investigations in active soft matter, hydrodynamics, and surface sciences, as well as promising systems for autonomous microfluidic operations. In contrast with most of the examples relying on organic drops or specifically treated substrates, here we describe the first system of nonreactive water drops in air that can propel themselves on a commercially available ordinary glass substrate that was used as received. This is achieved by exploiting the dynamic adsorption behavior of common n-alkyltrimethylammonium bromide (CnTAB) surfactants added to the drop. We precisely analyze the drop motion for a broad series of surfactants carrying n = 6 to 18 carbon atoms in their tail and establish how the motion characteristics (speed, probability of motion) are tuned by both the hydrophobicity and the concentration of the surfactant. We show that motion occurs regardless of the n value but only in a specific concentration range with a maximum speed at around one tenth of the critical micelle concentration (CMC/10) for most of the tested surfactants. Surfactants of intermediate hydrophobicity are shown to be the best candidates to power drops that can move at a high speed (1-10 cm s-1), the optimal performance being reached with [C12TAB] = 800 μM. We propose a mechanism where the motion originates from the anisotropic wettability of the substrate created by the electrostatic adsorption of surfactants beneath the moving drop. Simply drawing lines with a marker pen allows us to create guiding paths for drop motion and to achieve operations such as complex trajectory control, programmed drop fusion, drop refilling, as well as drop moving vertically against gravity. This work revisits the role of surfactants in dynamic wetting and self-propelled motion as well as brings an original strategy to build the future of microfluidics with lower-cost, simpler, and more autonomous portable devices that could be made available to everyone and everywhere.
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Affiliation(s)
- Pauline E Galy
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - Sergii Rudiuk
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - Mathieu Morel
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - Damien Baigl
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
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15
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Fedorets AA, Bormashenko E, Dombrovsky LA, Nosonovsky M. Symmetry of small clusters of levitating water droplets. Phys Chem Chem Phys 2020; 22:12239-12244. [PMID: 32432244 DOI: 10.1039/d0cp01804j] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Self-assembled clusters of condensed water microdroplets can levitate over a locally heated layer of water. Large clusters form hexagonally ordered (honeycomb) structures similar to colloidal crystals, while small (from one to several dozens of droplets) clusters possess special symmetry properties. Small clusters may demonstrate 4-fold, 5-fold, and 7-fold symmetry which is absent from large clusters and crystals. The symmetry properties of small cluster configurations are universal, i.e., they do not depend on the size of the droplets and details of the interactions between the droplets. The small cluster configurations may be compared with other types of symmetric objects in geometry.
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Affiliation(s)
- Alexander A Fedorets
- X-BIO Institute, University of Tyumen, 6 Volodarskogo St., Tyumen, 625003, Russia.
| | - Edward Bormashenko
- Department of Chemical Engineering, Biotechnology and Materials, Engineering Science Faculty, Ariel University, Ariel, 40700, Israel.
| | - Leonid A Dombrovsky
- X-BIO Institute, University of Tyumen, 6 Volodarskogo St., Tyumen, 625003, Russia. and Joint Institute for High Temperatures, 17A Krasnokazarmennaya St., Moscow, 111116, Russia.
| | - Michael Nosonovsky
- X-BIO Institute, University of Tyumen, 6 Volodarskogo St., Tyumen, 625003, Russia. and Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 North Cramer St., Milwaukee, WI 53211, USA.
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16
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Defying gravity: Drops that climb up a vertical wall of their own accord. J Colloid Interface Sci 2020; 562:608-613. [DOI: 10.1016/j.jcis.2019.10.120] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 10/30/2019] [Accepted: 10/31/2019] [Indexed: 11/19/2022]
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17
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Su J, Legchenkova I, Liu C, Lu C, Ma G, Bormashenko E, Liu Y. Faceted and Circular Droplet Spreading on Hierarchical Superhydrophobic Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:534-539. [PMID: 31880946 DOI: 10.1021/acs.langmuir.9b03347] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Bouncing of water droplets on the post-built superhydrophobic surfaces was studied. The topography of the surfaces was constituted by PDMS conical posts decorated with ZnO nanoparticles. Droplet impact on surface topographies built of posts with varied configuration and separation was studied under different Weber numbers. Faceted spreading and retraction of droplets were observed. Square-, pentagon-, and hexagon-shaped droplets were registered. It was shown that the nature of droplet spreading depended on both the Weber number and the topography of the post arrays. Even bouncing under small Weber numbers We ≅ 6.5 resulted in the Cassie-Wenzel transitions, starting from the area adjacent to the axis of droplets, and the area exposed to the wetting transitions scaled as [Formula: see text]. During spreading, two main stages were recorded as the kinematic (inertial) stage and the viscous stage. The viscous stage, in turn, appeared as a consequence of two substages governed by various time scaling laws. The faceted triple line was observed for the Cassie-like retraction of droplets.
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Affiliation(s)
- Junpeng Su
- Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education , Dalian University of Technology , Dalian 116024 , China
| | - Irina Legchenkova
- Chemical Engineering Department, Engineering Faculty , Ariel University , Ariel 407000 , Israel
| | - Cong Liu
- Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education , Dalian University of Technology , Dalian 116024 , China
| | - Chenguang Lu
- Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education , Dalian University of Technology , Dalian 116024 , China
| | - Guangyi Ma
- Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education , Dalian University of Technology , Dalian 116024 , China
| | - Edward Bormashenko
- Chemical Engineering Department, Engineering Faculty , Ariel University , Ariel 407000 , Israel
| | - Yahua Liu
- Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education , Dalian University of Technology , Dalian 116024 , China
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