1
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Hack MA, van der Linden MN, Wijshoff H, Snoeijer JH, Segers T. Ring-shaped colloidal patterns on saline water films. J Colloid Interface Sci 2024; 673:788-796. [PMID: 38906000 DOI: 10.1016/j.jcis.2024.06.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 06/01/2024] [Accepted: 06/03/2024] [Indexed: 06/23/2024]
Abstract
HYPOTHESIS Electrostatically stabilised colloidal particles destabilise when brought into contact with cations causing the particles to aggregate in clusters. When a drop with stabilised colloidal partices is deposited on a liquid film containing cations the delicate balance between the fluid-mechanical and physicochemical properties of the system governs the spreading dynamics and formation of colloidal particle clusters. EXPERIMENTS High-speed imaging and digital holographic microscopy were used to characterise the spreading process. FINDINGS We reveal that a spreading colloidal drop evolves into a ring-shaped pattern after it is deposited on a thin saline water film. Clustered colloidal particles aggregate into larger trapezoidally-shaped 'supraclusters'. Using a simple model we show that the trapezoidal shape of the supraclusters is determined by the transition from inertial spreading dynamics to Marangoni flow. These results may be of interest to applications such as wet-on-wet inkjet printing, where particle destabilisation and hydrodynamic flow coexist.
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Affiliation(s)
- Michiel A Hack
- Physics of Fluids Group, Max Planck Center Twente for Complex Fluid Dynamics, Faculty of Science and Technology, University of Twente, P.O. Box 217, Enschede, 7500 AE, the Netherlands
| | - Marjolein N van der Linden
- Physics of Fluids Group, Max Planck Center Twente for Complex Fluid Dynamics, Faculty of Science and Technology, University of Twente, P.O. Box 217, Enschede, 7500 AE, the Netherlands; Canon Production Printing Netherlands B.V., P.O. Box 101, Venlo, 5900 MA, the Netherlands
| | - Herman Wijshoff
- Canon Production Printing Netherlands B.V., P.O. Box 101, Venlo, 5900 MA, the Netherlands; Department of Mechanical Engineering, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600 MB, the Netherlands
| | - Jacco H Snoeijer
- Physics of Fluids Group, Max Planck Center Twente for Complex Fluid Dynamics, Faculty of Science and Technology, University of Twente, P.O. Box 217, Enschede, 7500 AE, the Netherlands
| | - Tim Segers
- BIOS/Lab on a Chip Group, Max Planck Center Twente for Complex Fluid Dynamics, MESA+ Institute for Nanotechnology, Faculty of Electrical Engineering, Mathematics and Computer Science, University of Twente, P.O. Box 217, Enschede, 7500 AE, the Netherlands.
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2
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Iasella S, Sharma R, Garoff S, Tilton RD. Interaction of impinging marangoni fields. J Colloid Interface Sci 2024; 653:807-820. [PMID: 37757714 DOI: 10.1016/j.jcis.2023.09.109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 09/09/2023] [Accepted: 09/17/2023] [Indexed: 09/29/2023]
Abstract
HYPOTHESIS Surface tension gradient driven Marangoni flows originating from multiple sources are important to many industrial and medical applications, but the theoretical literature focuses on single surfactant sources. Understanding how two spreading surfactant sources interact allows insights from single source experiments to be applied to multi-source applications. Two key features of multi-source spreading - source translation and source deformation - can be explained by transport modeling of a two-source system. MODELING Numerical simulations of two oleic acid disks placed at varying initial separation distances on a glycerol subphase were performed using COMSOL Multiphysics and compared to spreading of a single surfactant source. FINDINGS Interaction of two spreading sources can be split into three regimes: the independent regime - where each source is unaffected by the other, the interaction regime - where the presence of a second source alters one or more features of the spreading dynamics, and the quasi-one disk regime - where the two sources merge together. The translation of the sources, manifested as increasing separation distance between disk centers of mass, is driven by the flow fields within the subphase and the resultant surface deformation, while deformation of the sources occurs only once the surfactant fronts of the two sources meet.
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Affiliation(s)
- Steven Iasella
- Department of Chemical Engineering, Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Ramankur Sharma
- Department of Chemical Engineering, Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Stephen Garoff
- Department of Physics, Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Robert D Tilton
- Department of Chemical Engineering, Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA; Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
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3
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Fan Y, Wang Y. Deposition and Spread of Aqueous Pesticide Droplets on Hydrophobic/Superhydrophobic Surfaces by Fast Aggregation of Surfactants. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:5631-5640. [PMID: 37053578 DOI: 10.1021/acs.langmuir.3c00282] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Deposition and spread of aqueous droplets on hydrophobic/superhydrophobic surfaces are of great significance in many practical applications, such as spraying, coating, and printing, and particularly in improving pesticide utilization efficiency because the intrinsic hydrophobicity/superhydrophobicity of most plant leaves results in serious loss of water-based pesticides during spraying. It has been found that proper surfactants can promote the droplet spread on such surfaces. However, most reports involved the effects of surfactants on the spread of the gently released droplets over hydrophobic or highly hydrophobic substrates, while the situation on superhydrophobic substrates has rarely been explored. Moreover, high-speed impact makes it extremely difficult to deposit and spread the aqueous droplets on superhydrophobic surfaces; thus, the deposition and spread have just been achieved by surfactants in recent years. Here, we give an overview concerning the influence factors on the deposition and spreading performance of gently released and high-speed impacted droplets on hydrophobic/superhydrophobic substrates and emphasize the effects of fast aggregation of surfactants at the interface and in solution. We also outline perspectives on the future development of surfactant-assisted deposition and spreading after high-speed impact.
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Affiliation(s)
- Yaxun Fan
- CAS Key Laboratory of Colloid, Interface and Chemical Thermodynamics, CAS Research/Education Center for Excellence in Molecular Sciences and Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
| | - Yilin Wang
- CAS Key Laboratory of Colloid, Interface and Chemical Thermodynamics, CAS Research/Education Center for Excellence in Molecular Sciences and Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
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4
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Wang L, Chen L, Zheng X, Yu Z, Lv W, Sheng M, Wang L, Nie P, Li H, Guan D, Cui H. Multimodal Bubble Microrobot Near an Air-Water Interface. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2203872. [PMID: 36045100 DOI: 10.1002/smll.202203872] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 08/09/2022] [Indexed: 05/27/2023]
Abstract
The development of multifunctional and robust swimming microrobots working at the free air-liquid interface has encountered challenge as new manipulation strategies are needed to overcome the complicated interfacial restrictions. Here, flexible but reliable mechanisms are shown that achieve a remote-control bubble microrobot with multiple working modes and high maneuverability by the assistance of a soft air-liquid interface. This bubble microrobot is developed from a hollow Janus microsphere (JM) regulated by a magnetic field, which can implement switchable working modes like pusher, gripper, anchor, and sweeper. The collapse of the microbubble and the accompanying directional jet flow play a key role for functioning in these working modes, which is analogous to a "bubble tentacle." Using a simple gamepad, the orientation and the navigation of the bubble microrobot can be easily manipulated. In particular, a speed modulation method is found for the bubble microrobot, which uses vertical magnetic field to control the orientation of the JM and the direction of the bubble-induced jet flow without changing the fuel concentration. The findings demonstrate a substantial advance of the bubble microrobot specifically working at the air-liquid interface and depict some nonintuitive mechanisms that can help develop more complicated microswimmers.
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Affiliation(s)
- Leilei Wang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
- State Key Laboratory of Nonlinear Mechanics, Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Science, Beijing, 100190, China
| | - Li Chen
- School of Building Services Science and Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Xu Zheng
- State Key Laboratory of Nonlinear Mechanics, Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Science, Beijing, 100190, China
| | - Zexiong Yu
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Wenchao Lv
- School of Building Services Science and Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Minjia Sheng
- School of Building Services Science and Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Lina Wang
- School of Building Services Science and Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Pengcheng Nie
- State Key Laboratory of Nonlinear Mechanics, Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Science, Beijing, 100190, China
- School of Engineering Science, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hangyu Li
- State Key Laboratory of Nonlinear Mechanics, Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Science, Beijing, 100190, China
- School of Engineering Science, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Dongshi Guan
- State Key Laboratory of Nonlinear Mechanics, Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Science, Beijing, 100190, China
- School of Engineering Science, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Haihang Cui
- School of Building Services Science and Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
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5
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Fardin MA, Hautefeuille M, Sharma V. Spreading, pinching, and coalescence: the Ohnesorge units. SOFT MATTER 2022; 18:3291-3303. [PMID: 35416235 DOI: 10.1039/d2sm00069e] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Understanding the kinematics and dynamics of spreading, pinching, and coalescence of drops is critically important for a diverse range of applications involving spraying, printing, coating, dispensing, emulsification, and atomization. Hence experimental studies visualize and characterize the increase in size over time for drops spreading over substrates, or liquid bridges between coalescing drops, or the decrease in the radius of pinching necks during drop formation. Even for Newtonian fluids, the interplay of inertial, viscous, and capillary stresses can lead to a number of scaling laws, with three limiting self-similar cases: visco-inertial (VI), visco-capillary (VC) and inertio-capillary (IC). Though experiments are presented as examples of the methods of dimensional analysis, the lack of precise values or estimates for pre-factors, transitions, and scaling exponents presents difficulties for quantitative analysis and material characterization. In this tutorial review, we reanalyze and summarize an elaborate set of landmark published experimental studies on a wide range of Newtonian fluids. We show that moving beyond VI, VC, and IC units in favor of intrinsic timescale and lengthscale determined by all three material properties (viscosity, surface tension and density), creates a complementary system that we call the Ohnesorge units. We find that in spite of large differences in topological features, timescales, and material properties, the analysis of spreading, pinching and coalescing drops in the Ohnesorge units results in a remarkable collapse of the experimental datasets, highlighting the shared and universal features displayed in such flows.
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Affiliation(s)
- Marc A Fardin
- Université de Paris, CNRS, Institut Jacques Monod, F-75013 Paris, France.
| | - Mathieu Hautefeuille
- Université de Paris, CNRS, Institut Jacques Monod, F-75013 Paris, France.
- Facultad de Ciencias, Departamento de Fisica, Universidad Nacional Autónoma de México, Ciudad Universitaria, DF 04510, Mexico
- Institut de Biologie Paris Seine, UMR 7622, Sorbonne Université, 7 quai Saint Bernard, 75005 Paris, France
| | - Vivek Sharma
- Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60608, USA
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6
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Sauleda ML, Hsieh TL, Xu W, Tilton RD, Garoff S. Surfactant spreading on a deep subphase: Coupling of Marangoni flow and capillary waves. J Colloid Interface Sci 2022; 614:511-521. [PMID: 35121509 DOI: 10.1016/j.jcis.2022.01.142] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/21/2022] [Accepted: 01/22/2022] [Indexed: 02/05/2023]
Abstract
HYPOTHESIS Surfactant-driven Marangoni spreading generates a fluid flow characterized by an outwardly moving "Marangoni ridge". Spreading on thin and/or high viscosity subphases, as most of the prior literature emphasizes, does not allow the formation of capillary waves. On deep, low viscosity subphases, Marangoni stresses may launch capillary waves coupled with the Marangoni ridge, and new dependencies emerge for key spreading characteristics on surfactant thermodynamic and kinetic properties. EXPERIMENTS AND MODELING Computational and physical experiments were performed using a broad range of surfactants to report the post-deposition motion of the surfactant front and the deformation of the subphase surface. Modeling coupled the Navier-Stokes and advective diffusion equations with an adsorption model. Separate experiments employed tracer particles or an optical density method to track surfactant front motion or surface deformation, respectively. FINDINGS Marangoni stresses on thick subphases induce capillary waves, the slowest of which is co-mingled with the Marangoni ridge. Changing Marangoni stresses by varying the surfactant system alters the surfactant front velocity and the amplitude - but not the velocity - of the slowest capillary wave. As spreading progresses, the surfactant front and its associated surface deformation separate from the slowest moving capillary wave.
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Affiliation(s)
- Madeline L Sauleda
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA; Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Tsung-Lin Hsieh
- Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA; Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Wangrun Xu
- Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA; Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Robert D Tilton
- Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA; Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA; Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
| | - Stephen Garoff
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA; Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
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7
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Sauleda ML, Chu HCW, Tilton RD, Garoff S. Surfactant Driven Marangoni Spreading in the Presence of Predeposited Insoluble Surfactant Monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:3309-3320. [PMID: 33689367 DOI: 10.1021/acs.langmuir.0c03348] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
When an insoluble surfactant is deposited on the surface of a thin fluid film, stresses induced by surface tension gradients drive Marangoni spreading across the subphase surface. The presence of a predeposited layer of an insoluble surfactant alters that spreading. In this study, the fluid film was aqueous, the predeposited insoluble surfactant was dipalmitoylphosphatidylcholine (DPPC), and the deposited insoluble surfactant was oleic acid. An optical density-based method was used to measure subphase surface distortion, called the Marangoni ridge, associated with propagation of the spreading front. The movement of the Marangoni ridge was correlated with movement of surface tracer particles that indicated both the boundary between the two surfactant layers and the surface fluid velocities. As the deposited oleic acid monolayer spread, it compressed the predeposited DPPC monolayer. During spreading, the surface tension gradient extended into the predeposited monolayer, which was compressed nonuniformly, from the deposited monolayer. The spreading was so rapid that the compressed predeposited surfactant could not have been in quasi-equilibrium states during the spreading. As the initial concentrations of the predeposited surfactant were increased, the shape of the Marangoni ridge deformed. When the initial concentration of the predeposited surfactant reached about 70 A2/molecule, there was no longer a Marangoni ridge but rather a broadly distributed excess of fluid above the initial fluid height. The nonuniform compression of the annulus of the predeposited monolayer also caused tangential motion ahead of both the Marangoni ridge and the boundary between the two monolayers. Spreading ceased when the two monolayers reached the same final surface tension. The final area per molecule of the DPPC monolayer matched that expected from the equilibrium DPPC isotherm at the same final surface tension. Thus, at the end of spreading, there was a simple surface tension balance between the two distinct monolayers.
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Affiliation(s)
- Madeline L Sauleda
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
- Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Henry C W Chu
- Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Robert D Tilton
- Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Stephen Garoff
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
- Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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8
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Liu J, Guo X, Xu Y, Wu X. Spreading of Oil Droplets Containing Surfactants and Pesticides on Water Surface Based on the Marangoni Effect. Molecules 2021; 26:molecules26051408. [PMID: 33807893 PMCID: PMC7961330 DOI: 10.3390/molecules26051408] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 11/16/2022] Open
Abstract
Oil droplets containing surfactants and pesticides are expected to spread on a water surface, under the Marangoni effect, depending on the surfactant. Pesticides are transported into water through this phenomenon. A high-speed video camera was used to measure the movement of Marangoni ridges. Gas chromatography with an electron capture detector was used to analyze the concentration of the pesticide in water at different times. Oil droplets containing the surfactant and pesticide spread quickly on the water surface by Marangoni flow, forming an oil film and promoting emulsification of the oil–water interface, which enabled even transport of the pesticide into water, where it was then absorbed by weeds. Surfactants can decrease the surface tension of the water subphase after deposition, thereby enhancing the Marangoni effect in pesticide-containing oil droplets. The time and labor required for applying pesticides in rice fields can be greatly reduced by using the Marangoni effect to transport pesticides to the target.
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Affiliation(s)
| | | | - Yong Xu
- Correspondence: (Y.X.); (X.W.)
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9
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Venzmer J. Superspreading - Has the mystery been unraveled? Adv Colloid Interface Sci 2021; 288:102343. [PMID: 33359962 DOI: 10.1016/j.cis.2020.102343] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 12/08/2020] [Accepted: 12/09/2020] [Indexed: 10/22/2022]
Abstract
Superspreading is a fascinating phenomenon first observed about 30 years ago with dilute solutions of trisiloxane surfactants on hydrophobic substrates. Although many groups all over the world have contributed considerably to solve the scientific challenges involved, the reasons why only some trisiloxane surfactants promote superspreading, whereas others of similar chemical structure behave more like ordinary surfactants, has remained a mystery up to now. A number of original papers and reviews on superspreading have been published in recent years. The driving force still proposed today is most often Marangoni flow. This is, however, in contradiction with recent results showing that superspreading only starts after a surface tension gradient between apex and leading edge has been eliminated. From foam film experiments unrelated to wetting, there is evidence for "dangling" bilayers attached to the air/water interface only in case of the superspreading trisiloxane surfactants. By combining this and other published experimental findings, a new hypothesis of the mode of action is put forward: Advancing by "rolling action" at the leading edge, and the supply of surfactant by "unzippering" of the dangling bilayers all over the surface of the drop; this hypothesis even fulfills basic thermodynamic requirements.
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10
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Deodhar S, Rohilla P, Manivannan M, Thampi SP, Basavaraj MG. Robust Method to Determine Critical Micelle Concentration via Spreading Oil Drops on Surfactant Solutions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:8100-8110. [PMID: 32579372 DOI: 10.1021/acs.langmuir.0c00908] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The spreading of a liquid on another is often encountered in oil spills and coatings and is also of industrial relevance in pharmaceuticals and petrochemicals. In this study, the spreading of oil drops on aqueous solutions containing cationic, anionic, and nonionic surfactants over a wide range of surfactant concentrations is investigated. The spreading behavior quantified by measuring the time evolution of the projected area of the oil lens reveals the occurrence of a maximum, which is strongly dependent on the concentration of the surfactant in the aqueous solution. Our experiments show that this dependence is different at concentrations above and below the critical micelle concentration (CMC) of the surfactant and can be captured by two straight lines of different slopes. Interestingly, these two straight lines intersect at a concentration that coincides with the CMC of the surfactants in solution. We find that this behavior is universal as shown by performing experiments with different types of surfactants, their purity, and other system variables. Thus, we propose a method to unambiguously determine the CMC of surfactant solutions compared to the conventional techniques. The proposed method is simple, versatile, and applicable for the determination of CMC of both ionic and nonionic surfactants.
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Affiliation(s)
- Swaraj Deodhar
- Polymer Engineering and Colloid Sciences Lab, Department of Chemical Engineering, Indian Institute of Technology Madras, Sardar Patel Road, Adyar, IIT P.O., Chennai 600036, India
| | - Pankaj Rohilla
- Polymer Engineering and Colloid Sciences Lab, Department of Chemical Engineering, Indian Institute of Technology Madras, Sardar Patel Road, Adyar, IIT P.O., Chennai 600036, India
| | - M Manivannan
- Department of Applied Mechanics, Indian Institute of Technology Madras, Sardar Patel Road, Adyar, IIT P.O., Chennai 600036, India
| | - Sumesh P Thampi
- Polymer Engineering and Colloid Sciences Lab, Department of Chemical Engineering, Indian Institute of Technology Madras, Sardar Patel Road, Adyar, IIT P.O., Chennai 600036, India
| | - Madivala G Basavaraj
- Polymer Engineering and Colloid Sciences Lab, Department of Chemical Engineering, Indian Institute of Technology Madras, Sardar Patel Road, Adyar, IIT P.O., Chennai 600036, India
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11
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Motaghian M, Shirsavar R, Erfanifam M, Sabouhi M, van der Linden E, Stone HA, Bonn D, Habibi M. Rapid Spreading of a Droplet on a Thin Soap Film. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:14855-14860. [PMID: 31644302 PMCID: PMC6868707 DOI: 10.1021/acs.langmuir.9b02274] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 10/19/2019] [Indexed: 05/30/2023]
Abstract
We study the spreading of a droplet of surfactant solution on a thin suspended soap film as a function of dynamic surface tension and volume of the droplet. Radial growth of the leading edge (R) shows power-law dependence on time with exponents ranging roughly from 0.1 to 1 for different surface tension differences (Δσ) between the film and the droplet. When the surface tension of the droplet is lower than the surface tension of the film (Δσ > 0), we observe rapid spreading of the droplet with R ≈ tα, where α (0.4 < α < 1) is highly dependent on Δσ. Balance arguments assuming the spreading process is driven by Marangoni stresses versus inertial stresses yield α = 2/3. When the surface tension difference does not favor spreading (Δσ < 0), spreading still occurs but is slow with 0.1 < α < 0.2. This phenomenon could be used for stretching droplets in 2D and modifying thin suspended films.
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Affiliation(s)
- M. Motaghian
- Physics
and Physical Chemistry of Foods, Wageningen
University, Wageningen 6708 PB, Gelderland, The Netherlands
| | - R. Shirsavar
- Department
of Physics, Faculty of Science, University
of Zanjan, Zanjan 45371-38791, Zanjan, Iran
| | - M. Erfanifam
- Department
of Physics, Faculty of Science, University
of Zanjan, Zanjan 45371-38791, Zanjan, Iran
| | - M. Sabouhi
- Department
of Physics, Faculty of Science, University
of Zanjan, Zanjan 45371-38791, Zanjan, Iran
| | - E. van der Linden
- Physics
and Physical Chemistry of Foods, Wageningen
University, Wageningen 6708 PB, Gelderland, The Netherlands
| | - H. A. Stone
- Department
of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - D. Bonn
- Institute
of Physics, van der Waals-Zeeman Institute, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, North Holland, The Netherlands
| | - Mehdi Habibi
- Physics
and Physical Chemistry of Foods, Wageningen
University, Wageningen 6708 PB, Gelderland, The Netherlands
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12
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Wodlei F, Sebilleau J, Magnaudet J, Pimienta V. Marangoni-driven flower-like patterning of an evaporating drop spreading on a liquid substrate. Nat Commun 2018; 9:820. [PMID: 29483590 PMCID: PMC5827038 DOI: 10.1038/s41467-018-03201-3] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 01/26/2018] [Indexed: 11/09/2022] Open
Abstract
Drop motility at liquid surfaces is attracting growing interest because of its potential applications in microfluidics and artificial cell design. Here we report the unique highly ordered pattern that sets in when a millimeter-size drop of dichloromethane spreads on an aqueous substrate under the influence of surface tension, both phases containing a surfactant. Evaporation induces a Marangoni flow that forces the development of a marked rim at the periphery of the spreading film. At some point this rim breaks up, giving rise to a ring of droplets, which modifies the aqueous phase properties in such a way that the film recoils. The process repeats itself, yielding regular large-amplitude pulsations. Wrinkles form at the film surface due to an evaporative instability. During the dewetting stage, they emit equally spaced radial strings of droplets which, combined with those previously expelled from the rim, make the top view of the system resemble a flower. In liquid–liquid systems, Marangoni effects induced by surface tension gradients may result in the formation of peculiar self-assembled patterns. Wodlei et al. utilize this effect to draw a ‘flower’ by letting an oil droplet evaporate on an aqueous substrate in the presence of a cationic surfactant.
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Affiliation(s)
- F Wodlei
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Paul Sabatier, 118 route de Narbonne, 31062, Toulouse, Cedex 9, France
| | - J Sebilleau
- Institut de Mécanique des Fluides de Toulouse (IMFT), Université de Toulouse, CNRS, INPT, UPS, 31400 Toulouse, France
| | - J Magnaudet
- Institut de Mécanique des Fluides de Toulouse (IMFT), Université de Toulouse, CNRS, INPT, UPS, 31400 Toulouse, France
| | - V Pimienta
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Paul Sabatier, 118 route de Narbonne, 31062, Toulouse, Cedex 9, France.
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Wang X, Venzmer J, Bonaccurso E. Surfactant-Enhanced Spreading of Sessile Water Drops on Polypropylene Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:8322-8328. [PMID: 27448154 DOI: 10.1021/acs.langmuir.6b01357] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Spreading of water drops resting in equilibrium on polypropylene surfaces was initiated by dispensing surfactant-laden droplets on their apex. Upon contact of the two drops two processes were kicked-off: surfactant from the droplets spread along the water/air interface of the sessile drops and a train of capillary waves propagated along the sessile drops. The contact line of the sessile drops remained initially pinned and started spreading only when surfactant reached it while the capillary waves did not have an apparent effect on initiating drop spreading. However, surfactant influenced the propagation velocity of the capillary waves. Though the spreading dynamics of such nonhomogeneously mixed surfactant/water drops on polypropylene surfaces was initially different from that of homogeneously mixed drops, the later spreading dynamics was similar and was dominated by viscosity and surface tension in both cases. These results can help in discriminating the path of action of surfactants in bulk and at the water/air interface, which is also relevant for understanding phenomena such as superspreading.
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Affiliation(s)
- Xiang Wang
- Center of Smart Interfaces, Technical University Darmstadt , 64287 Darmstadt, Germany
- Mechanical Engineering Department, Dongguan University of Technology , 523808, Dongguan, China
| | - Joachim Venzmer
- Evonik Nutrition & Care GmbH , Goldschmidtstrasse 100, 45127 Essen, Germany
| | - Elmar Bonaccurso
- Center of Smart Interfaces, Technical University Darmstadt , 64287 Darmstadt, Germany
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14
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Sharma R, Corcoran TE, Garoff S, Przybycien TM, Tilton RD. Transport of a partially wetted particle at the liquid/vapor interface under the influence of an externally imposed surfactant generated Marangoni stress. Colloids Surf A Physicochem Eng Asp 2016; 521:49-60. [PMID: 28479673 DOI: 10.1016/j.colsurfa.2016.08.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Marangoni flows offer an interesting and useful means to transport particles at fluid interfaces with potential applications such as dry powder pulmonary drug delivery. In this article, we investigate the transport of partially wetted particles at a liquid/vapor interface under the influence of Marangoni flows driven by gradients in the surface excess concentration of surfactants. We deposit a microliter drop of soluble (sodium dodecyl sulfate aqueous solution) surfactant solution or pure insoluble liquid (oleic acid) surfactant on a water subphase and observe the transport of a pre-deposited particle. Following the previous observation by Wang et al. [1] that a surfactant front rapidly advances ahead of the deposited drop contact line initiates particle motion but then moves beyond the particle, we now characterize the two dominant, time- and position-dependent forces acting on the moving particle: 1) a surface tension force acting on the three-phase contact line around the particle periphery due to the surface tension gradient at the liquid/vapor interface which always accelerates the particle and 2) a viscous force acting on the immersed surface area of the particle which accelerates or decelerates the particle depending on the difference in the velocities of the liquid and particle. We find that the particle velocity evolves over time in two regimes. In the acceleration regime, the net force on the particle acts in the direction of particle motion, and the particle quickly accelerates and reaches a maximum velocity. In the deceleration regime, the net force on the particle reverses and the particle decelerates gradually and stops. We identify the parameters that affect the two forces acting on the particle, including the initial particle position relative to the surfactant drop, particle diameter, particle wettability, subphase thickness, and surfactant solubility. We systematically vary these parameters and probe the spatial and temporal evolution of the two forces acting on the particle as it moves along its trajectory in both regimes. We find that a larger particle always lags behind the smaller particle when placed at an equal initial distance from the drop. Similarly, particles more deeply engulfed in the subphase lag behind those less deeply engulfed. Further, the extent of particle transport is reduced as the subphase thickness decreases, due to the larger velocity gradients in the subphase recirculation flows.
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Affiliation(s)
- Ramankur Sharma
- Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States.,Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Timothy E Corcoran
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Stephen Garoff
- Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States.,Physics Department, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Todd M Przybycien
- Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States.,Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States.,Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Robert D Tilton
- Center for Complex Fluids Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States.,Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States.,Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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