1
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Figueroa ES, Trejo-Soto C, García-Ñustes M. A model for micro-front dynamics using a ϕ4 equation. CHAOS (WOODBURY, N.Y.) 2024; 34:023138. [PMID: 38412534 DOI: 10.1063/5.0187586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 01/27/2024] [Indexed: 02/29/2024]
Abstract
In this article, we propose a numerical model based on the ϕ4 equation to simulate the dynamics of a front inside a microchannel that features an imperfection at a sidewall to different flow rates. The micro-front displays pinning-depinning phenomena without damped oscillations in the aftermath. To model this behavior, we propose a ϕ4 model with a localized external force and a damping coefficient. Numerical simulations with a constant damping coefficient show that the front displays pinning-depinning phenomena showing damped oscillations once the imperfection is overcome. Replacing the constant damping coefficient with a parabolic spatial function, we reproduce accurately the experimental front-defect interaction.
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Affiliation(s)
- Elram S Figueroa
- Instituto de Física, Pontificia Universidad Católica de Valparaíso, Casilla 4059, Chile
| | - Claudia Trejo-Soto
- Instituto de Física, Pontificia Universidad Católica de Valparaíso, Casilla 4059, Chile
| | - Mónica García-Ñustes
- Instituto de Física, Pontificia Universidad Católica de Valparaíso, Casilla 4059, Chile
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2
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Kare SS, Ramkumar PK, Gao Y, Xu J, Finan JD. Connected Droplet Shape Analysis for Nanoflow Quantification in Thin Electroosmotic Micropumps and a Tunable Convex Lens Application. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:2569-2578. [PMID: 36763988 PMCID: PMC9949215 DOI: 10.1021/acs.langmuir.2c02875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 01/30/2023] [Indexed: 06/18/2023]
Abstract
Thin electroosmotic flow (EOF) micropumps can generate flow in confined spaces such as lab-on-a-chip microsystems and implantable drug delivery devices. However, status quo methods for quantifying flow and other important parameters in EOF micropumps depend on microfluidic interconnects or fluorescent particle tracking: methods that can be complex and error-prone. Here, we present a novel connected droplet shape analysis (CDSA) technique that simplifies flow rate and zeta potential quantification in thin EOF micropumps. We also show that a pair of droplets connected by an EOF pump can function as a tunable convex lens system (TCLS). We developed a biocompatible and all polymer EOF micropump with an SU-8 substrate and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) electrodes. We microdrilled a channel through the electrode/SU-8/electrode layers to realize a monolithic EOF micropump. Then, we deposited a pinned droplet on each end of the microchannel so that it connected them. By controlling the EOF between the droplets and measuring the corresponding change in their shape, we quantified the nanoliter EOF rate and zeta potential at the interface of SU-8 with two liquids (deionized water and a l-glutamate neurotransmitter solution). When the droplet pair and pump were used as a TCLS, CDSA successfully predicted how the focal length would change when the pump drove fluid from one droplet to another. In summary, CDSA is a simple low-cost technique for EOF rate and zeta potential measurement, and a pair of droplets connected by an EOF micropump can function as a TCLS without any moving parts.
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Affiliation(s)
- Sai Siva Kare
- Department of Mechanical and Industrial
Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Pradeep Kumar Ramkumar
- Department of Mechanical and Industrial
Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Yuan Gao
- Department of Mechanical and Industrial
Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Jie Xu
- Department of Mechanical and Industrial
Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - John Desmond Finan
- Department of Mechanical and Industrial
Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
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3
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Moradi Mehr S, Charsooghi MA, Businaro L, Habibi M, Moradi A. Capillary Pumping between Droplets on Superhydrophobic Surfaces. AIChE J 2022. [DOI: 10.1002/aic.17847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Shiva Moradi Mehr
- Department of Physics Institute for Advanced Studies in Basic Sciences (IASBS) Zanjan Iran
| | - Mohammad A. Charsooghi
- Department of Physics Institute for Advanced Studies in Basic Sciences (IASBS) Zanjan Iran
| | - Luca Businaro
- Italian National Research Council ‐ Institute for Photonics and Nanotechnologies (CNR ‐ IFN), via Cineto Romano 42 Rome Italy
| | - Mehdi Habibi
- Physics and Physical Chemistry of Foods Wageningen University AA Wageningen The Netherlands
| | - Ali‐Reza Moradi
- Department of Physics Institute for Advanced Studies in Basic Sciences (IASBS) Zanjan Iran
- School of Nano Science, Institute for Research in Fundamental Sciences (IPM) Tehran Iran
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4
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Moradi Mehr S, Businaro L, Habibi M, Moradi A. Collective behavior of evaporating droplets on superhydrophobic surfaces. AIChE J 2020. [DOI: 10.1002/aic.16284] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Shiva Moradi Mehr
- Department of PhysicsInstitute for Advanced Studies in Basic Sciences (IASBS) Zanjan 45195‐1159 Iran
| | - Luca Businaro
- Italian National Research Council ‐ Institute for Photonics and Nanotechnologies (CNR ‐ IFN) Rome Italy
| | - Mehdi Habibi
- Physics and Physical Chemistry of FoodsWageningen University 6700 AA Wageningen The Netherlands
| | - Ali‐Reza Moradi
- Department of PhysicsInstitute for Advanced Studies in Basic Sciences (IASBS) Zanjan 45195‐1159 Iran
- School of Nano ScienceInstitute for Research in Fundamental Sciences (IPM) Tehran 19395 19395‐5531 Iran
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5
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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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6
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Surface wettability and stability of chemically modified silicon, glass and polymeric surfaces via room temperature chemical vapor deposition. Colloids Surf A Physicochem Eng Asp 2019. [DOI: 10.1016/j.colsurfa.2019.03.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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7
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Lee Y, Seder I, Kim SJ. Influence of surface tension-driven network parameters on backflow strength. RSC Adv 2019; 9:10345-10351. [PMID: 35520946 PMCID: PMC9062321 DOI: 10.1039/c8ra09756a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 03/26/2019] [Indexed: 11/21/2022] Open
Abstract
This paper analyzes the effect of device elements on backflow of a surface tension-driven microfluidic device.
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Affiliation(s)
- Yonghun Lee
- Department of Mechanical Engineering
- Konkuk University
- Seoul
- Republic of Korea
| | - Islam Seder
- Department of Mechanical Engineering
- Konkuk University
- Seoul
- Republic of Korea
| | - Sung-Jin Kim
- Department of Mechanical Engineering
- Konkuk University
- Seoul
- Republic of Korea
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8
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Zhai Y, Wang A, Koh D, Schneider P, Oh KW. A robust, portable and backflow-free micromixing device based on both capillary- and vacuum-driven flows. LAB ON A CHIP 2018; 18:276-284. [PMID: 29199733 DOI: 10.1039/c7lc01077j] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
A robust, portable and backflow-free micromixing device using capillary-driven bypassing and syringe-assisted vacuum-driven pumping shows great promise for a variety of blood typing assays, agglutination-based assays and point-of-care or lab-on-a-chip testing applications.
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Affiliation(s)
- Yaguang Zhai
- SMALL (Sensors and MicroActuators Learning Lab)
- Department of Electrical Engineering
- University at Buffalo
- The State University of New York (SUNY at Buffalo)
- Buffalo
| | - Anyang Wang
- SMALL (Sensors and MicroActuators Learning Lab)
- Department of Electrical Engineering
- University at Buffalo
- The State University of New York (SUNY at Buffalo)
- Buffalo
| | - Domin Koh
- SMALL (Sensors and MicroActuators Learning Lab)
- Department of Electrical Engineering
- University at Buffalo
- The State University of New York (SUNY at Buffalo)
- Buffalo
| | - Philip Schneider
- SMALL (Sensors and MicroActuators Learning Lab)
- Department of Electrical Engineering
- University at Buffalo
- The State University of New York (SUNY at Buffalo)
- Buffalo
| | - Kwang W. Oh
- SMALL (Sensors and MicroActuators Learning Lab)
- Department of Electrical Engineering
- University at Buffalo
- The State University of New York (SUNY at Buffalo)
- Buffalo
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9
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Javadi K, Moezzi-Rafie H, Goodarzi-Ardakani V, Javadi A, Miller R. Flow physics exploration of surface tension driven flows. Colloids Surf A Physicochem Eng Asp 2017. [DOI: 10.1016/j.colsurfa.2016.12.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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10
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Shirsavar R, Nasiri M, Amjadi A, Nejati A, Sobhani SO, Habibi M. Rotation induced by uniform and non-uniform magnetic fields in a conducting fluid carrying an electric current. RSC Adv 2016. [DOI: 10.1039/c6ra24346k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
External magnetic field induces controllable rotation in a conducting fluid carrying an electric current.
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Affiliation(s)
- R. Shirsavar
- Department of Physics
- Faculty of Science
- University of Zanjan
- Zanjan
- Iran
| | - M. Nasiri
- Department of Physics
- Faculty of Science
- University of Zanjan
- Zanjan
- Iran
| | - A. Amjadi
- Department of Physics
- Sharif University of Technology
- Tehran
- Iran
| | - A. Nejati
- Physikalisches Institut and Bethe Center for Theoretical Physics
- Universität Bonn
- Germany
| | - S. O. Sobhani
- Department of Physics
- Sharif University of Technology
- Tehran
- Iran
- Department of Energy Engineering
| | - Mehdi Habibi
- Condensed Matter National Laboratory
- IPM
- Tehran
- Iran
- Institute of Physics
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11
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Davanlou A, Kumar R. Thermally induced collision of droplets in an immiscible outer fluid. Sci Rep 2015; 5:9531. [PMID: 25948547 PMCID: PMC5386213 DOI: 10.1038/srep09531] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 03/10/2015] [Indexed: 11/09/2022] Open
Abstract
Micro-total analysis systems (μTAS) have attracted wide attention and are identified as a promising solution for sample transport, filtration, chemical reactions, separation and detection. Despite their popularity, the selection of an appropriate mechanism for droplet transport and coalescence has always been a challenge. This paper investigates the use of Marangoni flow as a mechanism for levitating and transporting droplets on immiscible liquid films at higher speeds than is possible currently. For the first time, we show that it is possible to realize the natural coalescence of droplets through Marangoni effect without any external stimulation, and deliver the coalesced droplet to a certain destination through the use of surface tension gradients. The effects of shape and size on collision outcome are studied. Regions of coalescence and stretching separation of colliding droplets are delineated based on Weber number and impact number. In addition, the effect of viscosity on post collision regimes is studied. The findings in this fundamental study can be beneficial to many applications such as welding, drug delivery and microfluidics devices in controlling small droplets and targeting them to various locations.
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Affiliation(s)
- Ashkan Davanlou
- Mechanical &Aerospace Engineering, University of Central Florida, Orlando, Florida 32816, USA
| | - Ranganathan Kumar
- Mechanical &Aerospace Engineering, University of Central Florida, Orlando, Florida 32816, USA
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12
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Rodríguez-Rivas Á, Galván J, Romero-Enrique JM. Filling and wetting transitions on sinusoidal substrates: a mean-field study of the Landau-Ginzburg model. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:035101. [PMID: 25437528 DOI: 10.1088/0953-8984/27/3/035101] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We study the interfacial phenomenology of a fluid in contact with a one-dimensional array of infinitely long grooves of sinusoidal section, characterized by the periodicity length L and amplitude A. The system is modelled by the Landau-Ginzburg-Wilson functional, with fluid-substrate couplings which control the wettability of the substrate. We investigate the filling and wetting phenomena within the mean-field approximation, and compare with the predictions of the macroscopic and interfacial Hamiltonian theories. For large values of L and under bulk coexistence conditions, we observe first-order filling transitions between dry (D) and partially filled (F) interfacial states, and wetting transitions between partially filled F and completely wet (W) interfacial states of the same order as for the flat substrate. Depending on the order of the wetting transition, the transition temperature is either shifted towards lower temperatures for first-order wetting or it coincides with the wetting temperature on the flat substrate for continuous wetting. On the other hand, if the groove height is of order of the correlation length, only wetting transitions between D and W states are observed under bulk coexistence conditions. For this case, the transition temperature shift obeys approximately Wenzel's phenomenological law if the substrate favors first-order wetting, but it remains unshifted for continuous wetting. The borderline between the small and large L regimes correspond to a D - F - W triple point if wetting is first-order, and a D - F critical point for continuous wetting. Beyond bulk coexistence conditions, filling and first-order wetting transitions continue into off-coexistence filling and prewetting lines, which end up at critical points. Our findings show that the macroscopic theory only describes accurately the filling transition close to bulk coexistence and large L, while microscopic structure of the fluid is essential to understand wetting and filling away from bulk coexistence.
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Affiliation(s)
- Álvaro Rodríguez-Rivas
- Departamento de Física Atómica, Molecular y Nuclear, Area de Física Teórica, Universidad de Sevilla, Apartado de Correos 1065, 41080 Sevilla, Spain
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13
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Malijevský A. Filling and wetting transitions at grooved substrates. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:445006. [PMID: 24067670 DOI: 10.1088/0953-8984/25/44/445006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The wetting and filling properties of a fluid adsorbed on a solid grooved substrate are studied by means of a microscopic density functional theory. The grooved substrates are modelled using a solid slab, interacting with the fluid particles via long-range dispersion forces, to which a one-dimensional array of infinitely long rectangular grooves is sculpted. By investigating the effect of the groove periodicity and the width of the grooves and the ridges, a rich variety of different wetting morphologies is found. In particular, we show that for a saturated ambient gas, the adsorbent can occur in one of four wetting states characterized by (i) empty grooves, (ii) filled grooves, (iii) a formation of mesoscopic hemispherical caps (iv) a macroscopically wet surface. The character of the transition between particular regimes, that also extend off-coexistence, sensitively depends on the model geometry. The temperature at which the system becomes completely wet is considerably higher than that for a flat wall.
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Affiliation(s)
- Alexandr Malijevský
- E Hála Laboratory of Thermodynamics, Institute of Chemical Process Fundamentals, Academy of Sciences, 16502 Prague 6, Czech Republic. Department of Physical Chemistry, Institute of Chemical Technology, Prague, 166 28 Praha 6, Czech Republic
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