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Kim HH, Cho Y, Baek D, Rho KH, Park SH, Lee S. Parallelization of Microfluidic Droplet Junctions for Ultraviscous Fluids. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2205001. [PMID: 36310131 DOI: 10.1002/smll.202205001] [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: 08/15/2022] [Revised: 09/29/2022] [Indexed: 06/16/2023]
Abstract
The parallelization of multiple microfluidic droplet junctions has been successfully achieved so that the production throughput of the uniform microemulsions/particles has witnessed considerable progress. However, these advancements have been observed only in the case of a low viscous fluid (viscosity of 10-2 -10-3 Pa s). This study designs and fabricates a microfluidic device, enabling a uniform micro-emulsification of an ultraviscous fluid (viscosity of 3.5 Pa s) with a throughput of ≈330 000 droplets per hour. Multiple T-junctions of a dispersed oil phase, split from a single inlet, are connected into the single post-crossflow channel of a continuous water phase. In the proposed device, the continuous water phase undergoes a series circuit, wherein the resistances are continuously accumulated. The independent corrugations of the dispersed oil phase channel, under the theoretical guidance, compromise such increased resistances; the ratio of water to oil flow rates at each junction becomes consistent across T-junctions. Owing to the design being based on a fully 2D interconnection, single-step soft lithography is sufficient for developing the full device. This easy-to-craft architecture contrasts with the previous approach, wherein complicated 3D interconnections of the multiple junctions are involved, thereby facilitating the rapid uptake of high throughput droplet microfluidics for experts and newcomers alike.
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Affiliation(s)
- Hyeon Ho Kim
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea
| | - YongDeok Cho
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea
| | - Dongjae Baek
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea
| | - Kyung Hun Rho
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea
| | - Sung Hun Park
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea
| | - Seungwoo Lee
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea
- Department of Integrative Energy Engineering, Department of Biomicrosystem Technology and KU Photonics Center, Korea University, Seoul, 02841, Republic of Korea
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2
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Abstract
This review focuses on experimental work on nonlinear phenomena in microfluidics, which for the most part are phenomena for which the velocity of a fluid flowing through a microfluidic channel does not scale proportionately with the pressure drop. Examples include oscillations, flow-switching behaviors, and bifurcations. These phenomena are qualitatively distinct from laminar, diffusion-limited flows that are often associated with microfluidics. We explore the nonlinear behaviors of bubbles or droplets when they travel alone or in trains through a microfluidic network or when they assemble into either one- or two-dimensional crystals. We consider the nonlinearities that can be induced by the geometry of channels, such as their curvature or the bas-relief patterning of their base. By casting posts, barriers, or membranes─situated inside channels─from stimuli-responsive or flexible materials, the shape, size, or configuration of these elements can be altered by flowing fluids, which may enable autonomous flow control. We also highlight some of the nonlinearities that arise from operating devices at intermediate Reynolds numbers or from using non-Newtonian fluids or liquid metals. We include a brief discussion of relevant practical applications, including flow gating, mixing, and particle separations.
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Affiliation(s)
- Sarah Battat
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - David A Weitz
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States.,Department of Physics, Harvard University, Cambridge, Massachusetts 02138, United States.,Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts 02115, United States
| | - George M Whitesides
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
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3
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Asghari E, Moosavi A, Hannani SK. Non-Newtonian droplet-based microfluidics logic gates. Sci Rep 2020; 10:9293. [PMID: 32518389 PMCID: PMC7283233 DOI: 10.1038/s41598-020-66337-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 03/06/2020] [Indexed: 11/09/2022] Open
Abstract
Droplet-based microfluidic logic gates have many applications in diagnostic assays and biosciences due to their automation and the ability to be cascaded. In spite of many bio-fluids, such as blood exhibit non-Newtonian characteristics, all the previous studies have been concerned with the Newtonian fluids. Moreover, none of the previous studies has investigated the operating regions of the logic gates. In this research, we consider a typical AND/OR logic gate with a power-law fluid. We study the effects of important parameters such as the power-law index, the droplet length, the capillary number, and the geometrical parameters of the microfluidic system on the operating regions of the system. The results indicate that AND/OR states mechanism function in opposite directions. By increasing the droplet length, the capillary number and the power-law index, the operating region of AND state increases while the operating region of OR state reduces. Increasing the channel width will decrease the operating region of AND state while it increases the operating region of OR state. For proper operation of the logic gate, it should work in both AND/OR states appropriately. By combining the operating regions of these two states, the overall operating region of the logic gate is achieved.
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Affiliation(s)
- Elmira Asghari
- Center of Excellence in Energy Conversion (CEEC), School of Mechanical Engineering, Sharif University of Technology, Azadi Avenue, P. O. Box 11365-9567, Tehran, Iran
| | - Ali Moosavi
- Center of Excellence in Energy Conversion (CEEC), School of Mechanical Engineering, Sharif University of Technology, Azadi Avenue, P. O. Box 11365-9567, Tehran, Iran.
| | - Siamak Kazemzadeh Hannani
- Center of Excellence in Energy Conversion (CEEC), School of Mechanical Engineering, Sharif University of Technology, Azadi Avenue, P. O. Box 11365-9567, Tehran, Iran
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4
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Zhang C, Zhang X, Li Q, Wu L. Numerical Study of Bubble Breakup in Fractal Tree-Shaped Microchannels. Int J Mol Sci 2019; 20:ijms20215516. [PMID: 31694334 PMCID: PMC6862512 DOI: 10.3390/ijms20215516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 10/30/2019] [Accepted: 11/04/2019] [Indexed: 11/16/2022] Open
Abstract
Hydrodynamic behaviors of bubble stream flow in fractal tree-shaped microchannels is investigated numerically based on a two-dimensional volume of fluid (VOF) method. Bubble breakup is examined in each level of bifurcation and the transition of breakup regimes is discussed in particular. The pressure variations at the center of different levels of bifurcations are analyzed in an effort to gain further insight into the underlying mechanism of bubble breakup affected by multi-levels of bifurcations in tree-shaped microchannel. The results indicate that due to the structure of the fractal tree-shaped microchannel, both lengths of bubbles and local capillary numbers decrease along the microchannel under a constant inlet capillary number. Hence the transition from the obstructed breakup and obstructed-tunnel combined breakup to coalescence breakup is observed when the bubbles are flowing into a higher level of bifurcations. Compared with the breakup of the bubbles in the higher level of bifurcations, the behaviors of bubbles show stronger periodicity in the lower level of bifurcations. Perturbations grow and magnify along the flow direction and the flow field becomes more chaotic at higher level of bifurcations. Besides, the feedback from the unequal downstream pressure to the upstream lower level of bifurcations affects the bubble breakup and enhances the upstream asymmetrical behaviors.
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Affiliation(s)
- Chengbin Zhang
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu 210096, China; (C.Z.); (X.Z.); (Q.L.)
| | - Xuan Zhang
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu 210096, China; (C.Z.); (X.Z.); (Q.L.)
| | - Qianwen Li
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu 210096, China; (C.Z.); (X.Z.); (Q.L.)
| | - Liangyu Wu
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu 210096, China; (C.Z.); (X.Z.); (Q.L.)
- College of Electrical, Energy and Power Engineering, Yangzhou University, Yangzhou 225127, China
- Correspondence: ; Tel.: +86-25-8379-2483
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5
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Wang X, Liu Z, Pang Y. Breakup dynamics of droplets in an asymmetric bifurcation by μPIV and theoretical investigations. Chem Eng Sci 2019. [DOI: 10.1016/j.ces.2018.12.030] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Peng Y, Jin X, Zheng Y, Han D, Liu K, Jiang L. Direct Imaging of Superwetting Behavior on Solid-Liquid-Vapor Triphase Interfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29. [PMID: 28869679 DOI: 10.1002/adma.201703009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/17/2017] [Indexed: 05/11/2023]
Abstract
A solid-liquid-vapor interface dominated by a three-phase contact line usually serves as an active area for interfacial reactions and provides a vital clue to surface behavior. Recently, direct imaging of the triphase interface of superwetting interfaces on the microscale/nanoscale has attracted broad scientific attention for both theoretical research and practical applications, and has gradually become an efficient and intuitive approach to explore the wetting behaviors of various multiphase interfaces. Here, recent progress on characterizing the solid-liquid-vapor triphase interface on the microscale/nanoscale with diverse types of imaging apparatus is summarized. Moreover, the accurate, visible, and quantitative information that can be obtained shows the real interfacial morphology of the wetting behaviors of multiphase interfaces. On the basis of fundamental research, technical innovations in imaging and complicated multiphase interfaces of the superwetting surface are also briefly presented.
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Affiliation(s)
- Yun Peng
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing, 100191, P. R. China
| | - Xu Jin
- Research Institute of Petroleum, Exploration and Development, Petro China, Beijing, 100191, P. R. China
| | - Yongmei Zheng
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing, 100191, P. R. China
| | - Dong Han
- National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Kesong Liu
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing, 100191, P. R. China
| | - Lei Jiang
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing, 100191, P. R. China
- Laboratory of Bio-inspired Smart Interface Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
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7
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Sett A, Bano U, DasGupta S, Sarkar D, Mitra A, Das S, Dasgupta S. Capillary driven flow in wettability altered microchannel. AIChE J 2017. [DOI: 10.1002/aic.15787] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Ayantika Sett
- Dept. of Chemical Engineering; Indian Institute of Technology Kharagpur; Kharagpur 721302 India
| | - Uzma Bano
- Dept. of Chemical Engineering; Indian Institute of Technology Kharagpur; Kharagpur 721302 India
| | - Sunando DasGupta
- Dept. of Chemical Engineering; Indian Institute of Technology Kharagpur; Kharagpur 721302 India
| | - Debasish Sarkar
- Dept. of Chemical Engineering; University of Calcutta; Kolkata 700009 India
| | - Arijit Mitra
- Dept. of Metallurgical and Material Engineering; Indian Institute of Technology Kharagpur; Kharagpur 721302 India
| | - Siddhartha Das
- Dept. of Metallurgical and Material Engineering; Indian Institute of Technology Kharagpur; Kharagpur 721302 India
| | - Swagata Dasgupta
- Dept. of Chemistry; Indian Institute of Technology Kharagpur; Kharagpur 721302 India
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8
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Cybulski O, Jakiela S, Garstecki P. Between giant oscillations and uniform distribution of droplets: The role of varying lumen of channels in microfluidic networks. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:063008. [PMID: 26764805 DOI: 10.1103/physreve.92.063008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Indexed: 06/05/2023]
Abstract
The simplest microfluidic network (a loop) comprises two parallel channels with a common inlet and a common outlet. Recent studies that assumed a constant cross section of the channels along their length have shown that the sequence of droplets entering the left (L) or right (R) arm of the loop can present either a uniform distribution of choices (e.g., RLRLRL...) or long sequences of repeated choices (RRR...LLL), with all the intermediate permutations being dynamically equivalent and virtually equally probable to be observed. We use experiments and computer simulations to show that even small variation of the cross section along channels completely shifts the dynamics either into the strong preference for highly grouped patterns (RRR...LLL) that generate system-size oscillations in flow or just the opposite-to patterns that distribute the droplets homogeneously between the arms of the loop. We also show the importance of noise in the process of self-organization of the spatiotemporal patterns of droplets. Our results provide guidelines for rational design of systems that reproducibly produce either grouped or homogeneous sequences of droplets flowing in microfluidic networks.
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Affiliation(s)
- Olgierd Cybulski
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Slawomir Jakiela
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
- Department of Biophysics, Warsaw University of Life Sciences, Nowoursynowska 159, 02-776 Warsaw, Poland
| | - Piotr Garstecki
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
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9
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Kawano Y, Otsuka C, Sanzo J, Higgins C, Nirei T, Schilling T, Ishikawa T. Expanding imaging capabilities for microfluidics: applicability of darkfield internal reflection illumination (DIRI) to observations in microfluidics. PLoS One 2015; 10:e0116925. [PMID: 25748425 PMCID: PMC4352060 DOI: 10.1371/journal.pone.0116925] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Accepted: 12/16/2014] [Indexed: 01/09/2023] Open
Abstract
Microfluidics is used increasingly for engineering and biomedical applications due to recent advances in microfabrication technologies. Visualization of bubbles, tracer particles, and cells in a microfluidic device is important for designing a device and analyzing results. However, with conventional methods, it is difficult to observe the channel geometry and such particles simultaneously. To overcome this limitation, we developed a Darkfield Internal Reflection Illumination (DIRI) system that improved the drawbacks of a conventional darkfield illuminator. This study was performed to investigate its utility in the field of microfluidics. The results showed that the developed system could clearly visualize both microbubbles and the channel wall by utilizing brightfield and DIRI illumination simultaneously. The methodology is useful not only for static phenomena, such as clogging, but also for dynamic phenomena, such as the detection of bubbles flowing in a channel. The system was also applied to simultaneous fluorescence and DIRI imaging. Fluorescent tracer beads and channel walls were observed clearly, which may be an advantage for future microparticle image velocimetry (μPIV) analysis, especially near a wall. Two types of cell stained with different colors, and the channel wall, can be recognized using the combined confocal and DIRI system. Whole-slide imaging was also conducted successfully using this system. The tiling function significantly expands the observing area of microfluidics. The developed system will be useful for a wide variety of engineering and biomedical applications for the growing field of microfluidics.
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Affiliation(s)
- Yoshihiro Kawano
- The Department of Biomedical Engineering, Graduate School of Biomedical Engineering, Tohoku University, Sendai, Miyagi, Japan; Olympus Corporation, Shinjuku-Ku, Tokyo, Japan
| | | | - James Sanzo
- Olympus Scientific Solutions Americas, Waltham, Massachusetts, United States of America
| | - Christopher Higgins
- Olympus Scientific Solutions Americas, Waltham, Massachusetts, United States of America
| | | | | | - Takuji Ishikawa
- Department of Bioengineering and Robotics, Tohoku University, Sendai, Miyagi, Japan
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10
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Nguyen P, Mohaddes D, Riordon J, Fadaei H, Lele P, Sinton D. Fast Fluorescence-Based Microfluidic Method for Measuring Minimum Miscibility Pressure of CO2 in Crude Oils. Anal Chem 2015; 87:3160-4. [DOI: 10.1021/ac5047856] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Phong Nguyen
- Department
of Mechanical and Industrial Engineering, University of Toronto, 5 King’s College Road, Toronto, Ontario M5S 3G8, Canada
| | - Danyal Mohaddes
- Department
of Mechanical and Industrial Engineering, University of Toronto, 5 King’s College Road, Toronto, Ontario M5S 3G8, Canada
| | - Jason Riordon
- Department
of Mechanical and Industrial Engineering, University of Toronto, 5 King’s College Road, Toronto, Ontario M5S 3G8, Canada
| | - Hossein Fadaei
- Department
of Mechanical and Industrial Engineering, University of Toronto, 5 King’s College Road, Toronto, Ontario M5S 3G8, Canada
| | - Pushan Lele
- Department
of Mechanical and Industrial Engineering, University of Toronto, 5 King’s College Road, Toronto, Ontario M5S 3G8, Canada
| | - David Sinton
- Department
of Mechanical and Industrial Engineering, University of Toronto, 5 King’s College Road, Toronto, Ontario M5S 3G8, Canada
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11
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Abstract
Droplet microfluidics may soon change the paradigm of performing chemical analyses and related instrumentation.
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Affiliation(s)
- Evgenia Yu Basova
- Masaryk University
- CEITEC, Central European Institute Technology
- Brno
- Czech Republic
| | - Frantisek Foret
- Masaryk University
- CEITEC, Central European Institute Technology
- Brno
- Czech Republic
- Institute of Analytical Chemistry of the Academy of Sciences of the Czech Republic
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12
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Wang WS, Vanapalli SA. Millifluidics as a simple tool to optimize droplet networks: Case study on drop traffic in a bifurcated loop. BIOMICROFLUIDICS 2014; 8:064111. [PMID: 25553188 PMCID: PMC4257966 DOI: 10.1063/1.4902910] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 11/17/2014] [Indexed: 05/07/2023]
Abstract
We report that modular millifluidic networks are simpler, more cost-effective alternatives to traditional microfluidic networks, and they can be rapidly generated and altered to optimize designs. Droplet traffic can also be studied more conveniently and inexpensively at the millimeter scale, as droplets are readily visible to the naked eye. Bifurcated loops, ladder networks, and parking networks were made using only Tygon(®) tubing and plastic T-junction fittings and visualized using an iPod(®) camera. As a case study, droplet traffic experiments through a millifluidic bifurcated loop were conducted, and the periodicity of drop spacing at the outlet was mapped over a wide range of inlet drop spacing. We observed periodic, intermittent, and aperiodic behaviors depending on the inlet drop spacing. The experimentally observed periodic behaviors were in good agreement with numerical simulations based on the simple network model. Our experiments further identified three main sources of intermittency between different periodic and/or aperiodic behaviors: (1) simultaneous entering and exiting events, (2) channel defects, and (3) equal or nearly equal hydrodynamic resistances in both sides of the bifurcated loop. In cases of simultaneous events and/or channel defects, the range of input spacings where intermittent behaviors are observed depends on the degree of inherent variation in input spacing. Finally, using a time scale analysis of syringe pump fluctuations and experiment observation times, we find that in most cases, more consistent results can be generated in experiments conducted at the millimeter scale than those conducted at the micrometer scale. Thus, millifluidic networks offer a simple means to probe collective interactions due to drop traffic and optimize network geometry to engineer passive devices for biological and material analysis.
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Affiliation(s)
- William S Wang
- Department of Chemical Engineering , Texas Tech University , Lubbock, Texas 79409-3121, USA
| | - Siva A Vanapalli
- Department of Chemical Engineering , Texas Tech University , Lubbock, Texas 79409-3121, USA
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13
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Huerre A, Miralles V, Jullien MC. Bubbles and foams in microfluidics. SOFT MATTER 2014; 10:6888-902. [PMID: 24913678 DOI: 10.1039/c4sm00595c] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Microfluidics offers great tools to produce highly-controlled dispersions of gas into liquid, from isolated bubbles to organized microfoams. Potential technological applications are manifold, from novel materials to scaffolds for tissue engineering or enhanced oil recovery. More fundamentally, microfluidics makes it possible to investigate the physics of complex systems such as foams at scales where the capillary forces become dominant, in model experiments involving few well-controlled parameters. In this context, this review does not have the ambition to detail in a comprehensive manner all the techniques and applications involving bubbles and foams in microfluidics. Rather, it focuses on particular consequences of working at the microscale, under confinement, and hopes to provide insight into the physics of such systems. The first part of this work focuses on bubbles, and more precisely on (i) bubble generation, where the confinement can suppress capillary instabilities while inertial effects may play a role, and (ii) bubble dynamics, paying special attention to the lubrication film between bubble and wall and the influence of confinement. The second part addresses the formation and dynamics of microfoams, emphasizing structural differences from macroscopic foams and the influence of the confinement.
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Affiliation(s)
- Axel Huerre
- MMN, UMR CNRS Gulliver 7083, PSL research University, ESPCI ParisTech, 10 rue Vauquelin, 75005 Paris, France.
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14
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Kadivar E, Herminghaus S, Brinkmann M. Droplet sorting in a loop of flat microfluidic channels. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:285102. [PMID: 23751984 DOI: 10.1088/0953-8984/25/28/285102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Motivated by recent experiments, we numerically study the droplet traffic in microfluidic channels forming an asymmetric loop with a long and a short arm. The loop is connected to an inlet and an outlet channel by two right angled T-junctions. Assuming flat channels, we employ the boundary element method (BEM) to numerically solve the two-dimensional Darcy equation that governs two phase flow in the Hele-Shaw limit. The occurrence of different sorting regimes is summarized in sorting diagrams in terms of droplet size, distance between consecutive droplets in the inlet channel, and loop asymmetry for mobility ratios of the liquid phases larger and smaller than one. For large droplet distances, the traffic is regulated by the ratio of the total hydraulic resistances of the long and short arms. At high droplet densities and below a critical droplet size, droplet-droplet collisions are observed for both mobility ratios.
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Affiliation(s)
- Erfan Kadivar
- Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, D-37077 Göttingen, Germany.
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15
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Amon A, Schmit A, Salkin L, Courbin L, Panizza P. Path selection rules for droplet trains in single-lane microfluidic networks. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:013012. [PMID: 23944554 DOI: 10.1103/physreve.88.013012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Indexed: 05/23/2023]
Abstract
We investigate the transport of periodic trains of droplets through microfluidic networks having one inlet, one outlet, and nodes consisting of T junctions. Variations of the dilution of the trains, i.e., the distance between drops, reveal the existence of various hydrodynamic regimes characterized by the number of preferential paths taken by the drops. As the dilution increases, this number continuously decreases until only one path remains explored. Building on a continuous approach used to treat droplet traffic through a single asymmetric loop, we determine selection rules for the paths taken by the drops and we predict the variations of the fraction of droplets taking these paths with the parameters at play including the dilution. Our results show that as dilution decreases, the paths are selected according to the ascending order of their hydrodynamic resistance in the absence of droplets. The dynamics of these systems controlled by time-delayed feedback is complex: We observe a succession of periodic regimes separated by a wealth of bifurcations as the dilution is varied. In contrast to droplet traffic in single asymmetric loops, the dynamical behavior in networks of loops is sensitive to initial conditions because of extra degrees of freedom.
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Affiliation(s)
- A Amon
- IPR, CNRS, UMR No. 6251, Campus Beaulieu, Université Rennes 1, 35042 Rennes, France
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16
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Paxson AT, Varanasi KK. Self-similarity of contact line depinning from textured surfaces. Nat Commun 2013; 4:1492. [PMID: 23422660 PMCID: PMC3586717 DOI: 10.1038/ncomms2482] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 01/14/2013] [Indexed: 11/28/2022] Open
Abstract
The mobility of drops on surfaces is important in many biological and industrial processes, but the phenomena governing their adhesion, which is dictated by the morphology of the three-phase contact line, remain unclear. Here we describe a technique for measuring the dynamic behaviour of the three-phase contact line at micron length scales using environmental scanning electron microscopy. We examine a superhydrophobic surface on which a drop's adhesion is governed by capillary bridges at the receding contact line. We measure the microscale receding contact angle of each bridge and show that the Gibbs criterion is satisfied at the microscale. We reveal a hitherto unknown self-similar depinning mechanism that shows how some hierarchical textures such as lotus leaves lead to reduced pinning, and counter-intuitively, how some lead to increased pinning. We develop a model to predict adhesion force and experimentally verify the model's broad applicability on both synthetic and natural textured surfaces.
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Affiliation(s)
- Adam T. Paxson
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Kripa K. Varanasi
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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17
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Wei Z, Amponsah PK, Al-Shatti M, Nie Z, Bandyopadhyay BC. Engineering of polarized tubular structures in a microfluidic device to study calcium phosphate stone formation. LAB ON A CHIP 2012; 12:4037-40. [PMID: 22960772 PMCID: PMC3503450 DOI: 10.1039/c2lc40801e] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
This communication describes the formation of tubular structures with a circular cross-section by growing epithelial cells in a microfluidic (MF) device. Here we show for the first time that it is possible to form a monolayer of polarized cells, embedded within the MF device which can function as an in vivo epithelia. We showed: i) the overexpression of specific protein(s) of interest (i.e., ion channel and transport proteins) is feasible inside tubular structures in MFs; ii) the functional kinetic information of Ca(2+) in cells can be measured by microflurometry using cell permeable Ca(2+) probe under confocal microscope; and iii) calcium phosphate stones can be produced in real time in MFs with Ca(2+) transporting epithelia. These data suggest that tubular structures inside this MF platform can be used as a suitable model to understand the molecular and pharmacological basis of calcium phosphate stone formation in the epithelial or other similar cellular micro environments.
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Affiliation(s)
- Zengjiang Wei
- Research Institute of Materials Science, South China University of Technology, Guangzhou, 510640, China
- Department of Chemistry and Biochemistry, University of Maryland College Park, MD, 20742, USA
| | - Prince K. Amponsah
- Calcium Signaling Laboratory, DVA Medical Center, 50 Irving Street NW, Washington, DC, 20422, USA
| | - Mariyam Al-Shatti
- Calcium Signaling Laboratory, DVA Medical Center, 50 Irving Street NW, Washington, DC, 20422, USA
| | - Zhihong Nie
- Department of Chemistry and Biochemistry, University of Maryland College Park, MD, 20742, USA
| | - Bidhan C. Bandyopadhyay
- Calcium Signaling Laboratory, DVA Medical Center, 50 Irving Street NW, Washington, DC, 20422, USA
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Abstract
Microfluidics, a field that has been well-established for several decades, has seen extensive applications in the areas of biology, chemistry, and medicine. However, it might be very hard to imagine how such soft microfluidic devices would be used in other areas, such as electronics, in which stiff, solid metals, insulators, and semiconductors have previously dominated. Very recently, things have radically changed. Taking advantage of native properties of microfluidics, advances in microfluidics-based electronics have shown great potential in numerous new appealing applications, e.g. bio-inspired devices, body-worn healthcare and medical sensing systems, and ergonomic units, in which conventional rigid, bulky electronics are facing insurmountable obstacles to fulfil the demand on comfortable user experience. Not only would the birth of microfluidic electronics contribute to both the microfluidics and electronics fields, but it may also shape the future of our daily life. Nevertheless, microfluidic electronics are still at a very early stage, and significant efforts in research and development are needed to advance this emerging field. The intention of this article is to review recent research outcomes in the field of microfluidic electronics, and address current technical challenges and issues. The outlook of future development in microfluidic electronic devices and systems, as well as new fabrication techniques, is also discussed. Moreover, the authors would like to inspire both the microfluidics and electronics communities to further exploit this newly-established field.
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Affiliation(s)
- Shi Cheng
- Ericsson AB, Borgarfjordsgatan 18, SE-164 80, Stockholm, Sweden.
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