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Wang DQ, Wang ZJ, Wang SY, Yang YR, Zheng SF, Lee DJ, Wang XD. Coalescence-Induced Jumping of Nanodroplets in a Perpendicular Electric Field: A Molecular Dynamics Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024. [PMID: 38298055 DOI: 10.1021/acs.langmuir.3c03758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
Coalescence-induced jumping has promised a substantial reduction in the droplet detachment size and consequently shows great potential for heat-transfer enhancement in dropwise condensation. In this work, using molecular dynamics simulations, the evolution dynamics of the liquid bridge and the jumping velocity during coalescence-induced nanodroplet jumping under a perpendicular electric field are studied for the first time to further promote jumping. It is found that using a constant electric field, the jumping performance at the small intensity is weakened owing to the continuously decreased interfacial tension. There is a critical intensity above which the electric field can considerably enhance the stretching effect with a stronger liquid-bridge impact and, hence, improve the jumping performance. For canceling the inhibition effect of the interfacial tension under the condition of the weak electric field, a square-pulsed electric field with a paused electrical effect at the expansion stage of the liquid bridge is proposed and presents an efficient nanodroplet jumping even using the weak electric field.
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Affiliation(s)
- Dan-Qi Wang
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
| | - Zi-Jie Wang
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
| | - Shao-Yu Wang
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
| | - Yan-Ru Yang
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
| | - Shao-Fei Zheng
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
| | - Duu-Jong Lee
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon Tong 999077, Hong Kong
- Department of Chemical Engineering and Materials Science, Yuan Ze University, Chung-Li 32003, Taiwan
| | - Xiao-Dong Wang
- State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing 102206, China
- Research Center of Engineering Thermophysics, North China Electric Power University, Beijing 102206, China
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2
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Liao J, Majidi C, Sitti M. Liquid Metal Actuators: A Comparative Analysis of Surface Tension Controlled Actuation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2300560. [PMID: 37358049 DOI: 10.1002/adma.202300560] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 06/09/2023] [Indexed: 06/27/2023]
Abstract
Liquid metals, with their unique combination of electrical and mechanical properties, offer great opportunities for actuation based on surface tension modulation. Thanks to the scaling laws of surface tension, which can be electrochemically controlled at low voltages, liquid metal actuators stand out from other soft actuators for their remarkable characteristics such as high contractile strain rates and higher work densities at smaller length scales. This review summarizes the principles of liquid metal actuators and discusses their performance as well as theoretical pathways toward higher performances. The objective is to provide a comparative analysis of the ongoing development of liquid metal actuators. The design principles of the liquid metal actuators are analyzed, including low-level elemental principles (kinematics and electrochemistry), mid-level structural principles (reversibility, integrity, and scalability), and high-level functionalities. A wide range of practical use cases of liquid metal actuators from robotic locomotion and object manipulation to logic and computation is reviewed. From an energy perspective, strategies are compared for coupling the liquid metal actuators with an energy source toward fully untethered robots. The review concludes by offering a roadmap of future research directions of liquid metal actuators.
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Affiliation(s)
- Jiahe Liao
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569, Stuttgart, Germany
| | - Carmel Majidi
- Robotics Institute, Mechanical Engineering, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA, 15213, USA
| | - Metin Sitti
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569, Stuttgart, Germany
- Institute for Biomedical Engineering, ETH Zürich, Zürich, 8092, Switzerland
- School of Medicine, College of Engineering, Koç University, Istanbul, 34450, Turkey
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3
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Kaushal A, Shoval S, Binks BP, Bormashenko E. Universality of Scaling Laws Governing Contact and Spreading Time Spans of Bouncing Liquid Marbles and its Physical Origin. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:12488-12496. [PMID: 37604671 DOI: 10.1021/acs.langmuir.3c01710] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
The impact of liquid marbles coated with a diversity of hydrophobic powders with various solid substrates, including hydrophobic, hydrophilic, and superhydrophobic ones, was investigated. The contact time of the bouncing marbles was studied. Universal scaling behavior of the contact time tc as a function of the Weber number (We) was established; the scaling law tc = tc(We) was independent of the kind of powder and the type of solid substrate. The total contact time consists of spreading time and retraction time. It is weakly dependent on We and this is true for all kinds of studied powders and substrates. This observation hints to the surface tension/inertia spring model governing the impact. By contrast, the spreading time ts scales as [Formula: see text], n = 0.28 - 0.30 ± 0.002. We relate the origin of this scaling law to the viscous dissipation occurring within the spreading marbles. The retraction time tr grows weakly with the Weber number. The scaling law was changed at threshold values of We ≅ 15-20. It is reasonable to explain this change with the breaking of the Leidenfrost regime of spreading under high values of We.
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Affiliation(s)
- Abhishek Kaushal
- Chemical Engineering Department, Engineering Faculty, Ariel University, P.O.B. 3, 407000 Ariel, Israel
- Department of Industrial Engineering and Management, Faculty of Engineering, Ariel University, P.O.B. 3, Ariel 407000, Israel
| | - Shraga Shoval
- Department of Industrial Engineering and Management, Faculty of Engineering, Ariel University, P.O.B. 3, Ariel 407000, Israel
| | - Bernard P Binks
- Department of Chemistry, University of Hull, Hull HU6 7RX, U.K
| | - Edward Bormashenko
- Chemical Engineering Department, Engineering Faculty, Ariel University, P.O.B. 3, 407000 Ariel, Israel
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Zhao P, Yan L, Gao X. Millirobot Based on a Phase-Transformable Magnetorheological Liquid Metal. ACS APPLIED MATERIALS & INTERFACES 2023; 15:37658-37667. [PMID: 37503740 DOI: 10.1021/acsami.3c06648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Droplet robots have attracted much attention in recent years due to their large-scale deformability and flexible mobility in confined spaces. However, droplet robots are always difficult to maintain rigid shapes, making them difficult to manipulate objects with large inertia. Moreover, their low conductivity makes them unable to complete tasks such as circuit repair. Herein, a millirobot made from magnetorheological liquid metal is proposed to address the problems. Specifically, the magnetorheological liquid metal (MLM) robot is made by engulfing iron particles into gallium-indium alloy, and the mass fraction of the MLM robot is determined by microscopic observation and rheological test. The MLM robot possesses both solid and liquid properties, enabling the robot with plasticity, large-scale deformability, good conductivity, motion flexibility, and good object manipulation. The MLM robot can achieve almost all of the functions of existing droplet robots, including splitting, merging, navigating in narrow channels, and pushing objects. In addition, it can also accomplish some other tasks that are difficult for existing droplet robots, such as pulling large objects, repairing damaged circuits selectively and reversibly, and repairing suspended circuits through plasticity. The demos show that MLM robots can traverse narrow spaces and repair circuit damage selectively and reversibly. It is believed that MLM robots can enrich diverse functionalities in the future.
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Affiliation(s)
- Peiran Zhao
- School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China
| | - Liang Yan
- School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China
- Ningbo Institute of Technology, Beihang University, Ningbo 315800, China
- Tianmushan Laboratory, Hangzhou 310023, China
- Science and Technology on Aircraft Control Laboratory, Beihang University, Beijing 100191, China
| | - Xiaoshan Gao
- School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China
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Dai L, Wu X, Hu Z, Hou H, Gao S, Lin Y, Yuan Z. An Oscillation System Based on a Liquid Metal Droplet and Pillars under a Direct Current Electric Field. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023. [PMID: 37377336 DOI: 10.1021/acs.langmuir.3c00622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
Gallium-based liquid metal is a new class of material that has attracted extensive attention due to its excellent deformation characteristics and great potential in applications. Based on the deformation characteristics of liquid metal droplets, researchers have developed many oscillation systems composed of gallium indium tin alloy (GaInSn) droplet and graphite, or aluminum-doped gallium indium alloy (Al-GaIn24.5) droplet and iron, and so on. Rather than the oxidation and deoxidation mechanisms used in previous systems, an oscillation system that can achieve gallium indium alloy (EGaIn) droplet oscillation with the frequency of 0-29 Hz is designed depending on the interactions between the electric field, pillars, sodium hydroxide, and the droplet. The forces on the droplet are analyzed specifically, which have a great influence on droplet deformation. Additionally, the effects of factors such as voltage, the concentration of sodium hydroxide (NaOH) solution, and droplet size on the droplet oscillation are elucidated based on the force analysis, enabling the flexible control of the oscillation frequency and amplitude of the droplet. This work provides a new perspective on the design of oscillation systems and further enhances our understanding of the deformation of gallium-based liquid metal droplets.
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Affiliation(s)
- Liyu Dai
- Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China
| | - Xiaomin Wu
- Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China
| | - Zhifeng Hu
- Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China
| | - Huimin Hou
- Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China
| | - Sihang Gao
- Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China
| | - Yukai Lin
- Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China
| | - Zhiping Yuan
- Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
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Banerjee U, Shyam S, Mitra SK. Magnetic Control of Water Droplet Impact onto Ferrofluid Lubricated Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:4049-4059. [PMID: 36893478 DOI: 10.1021/acs.langmuir.2c03404] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Controlling the impact process of a droplet impacting a liquid film has remained a wide-open challenge. The existing passive techniques lack precise on-demand control of the impact dynamics of droplets. The present study introduces a magnet-assisted approach to control water droplets' impact dynamics. We show that by incorporating a thin, magnetically active ferrofluid film, the overall droplet impact phenomena of the water droplets could be controlled. It is found that by modifying the distribution of the magnetic nanoparticles (MNPs) present inside the ferrofluid using a permanent magnet, the spreading and retraction behavior of the droplet could be significantly controlled. In addition to that, we also show that by altering the impact Weber number (Wei), and the magnetic Bond number (Bom), the outcomes of droplet impact could be precisely controlled. We reveal the role of the various forces on the consequential effects of droplet impact with the help of phase maps. Without the magnetic field, we discovered that the droplet impact on ferrofluid film results in no-splitting, jetting, and splashing regimes. On the other hand, the presence of magnetic field results in the no-splitting and jetting regime. However, beyond a critical magnetic field, the ferrofluid film gets transformed into an assembly of spikes. In such scenarios, the droplet impact only results in no-splitting and splashing regimes, while the jetting regime remains absent. The outcome of our study may find potential applications in chemical engineering, material synthesis, and three-dimensional (3D) printing where the control and optimization of the droplet impact process are desirable.
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Affiliation(s)
- Utsab Banerjee
- Micro & Nano-scale Transport Laboratory, Waterloo Institute for Nanotechnology, Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Sudip Shyam
- Micro & Nano-scale Transport Laboratory, Waterloo Institute for Nanotechnology, Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Sushanta K Mitra
- Micro & Nano-scale Transport Laboratory, Waterloo Institute for Nanotechnology, Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
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Lathia R, Nampoothiri KN, Sagar N, Bansal S, Modak CD, Sen P. Advances in Microscale Droplet Generation and Manipulation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:2461-2482. [PMID: 36779356 DOI: 10.1021/acs.langmuir.2c02905] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Microscale droplet generation and manipulation have widespread applications in numerous fields, from biochemical assays to printing and additive manufacturing. There are several techniques for droplet handling. Most techniques, however, can generate and work with only a limited range of droplet sizes. Furthermore, there are constraints regarding the workable variety of fluid properties (e.g., viscosity, surface tension, mass loading, etc.). Recent works have focused on developing techniques to overcome these limitations. This feature article discusses advances in this area that cover a wide range of droplet sizes from subpicoliter to microliter.
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Affiliation(s)
- Rutvik Lathia
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Krishnadas Narayanan Nampoothiri
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India
- Department of Mechanical Engineering, Amrita School of Engineering, Amrita Vishwa Vidyapeetham, Chennai 601103, India
| | - Nitish Sagar
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Shubhi Bansal
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India
- University College London, London WC1E 6BT, U.K
| | - Chandantaru Dey Modak
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India
- Laboratoire de Biophysique et Evolution, UMR CNRS-ESPCI 8231 Chimie Biologie Innovation, PSL University, ESPCI Paris, 10 rue Vauquelin, 75005 Paris, France
| | - Prosenjit Sen
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, India
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Chen Y, Chen X, Zhu Z, Sun M, Li S, Gan M, Tang SY, Li W, Zhang S, Sun L, Li X. 3D actuation of foam-core liquid metal droplets. SOFT MATTER 2023; 19:1293-1299. [PMID: 36524440 DOI: 10.1039/d2sm01349e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Precise manipulation of liquid metal (LM) droplets possesses the potential to enable a wide range of applications in reconfigurable electronics, robotics, and microelectromechanical systems. Although a variety of methods have been explored to actuate LM droplets on a 2D plane, versatile 3D manipulation remains a challenge due to the difficulty in overcoming their heavy weight. Here, foam-core liquid metal (FCLM) droplets that can maintain the surface properties of LM while significantly reducing the density are developed, enabling 3D manipulation in an electrolyte. The FCLM droplet is fabricated by coating LM on the surface of a copper-grafted foam sphere. The actuation of the FCLM droplet is realized by electrically inducing Marangoni flow on the LM surface. Two motion modes of the FCLM droplet are observed and studied and the actuation performance is characterized. Multiple FCLM droplets can be readily controlled to form 3D structures, demonstrating their potential to be further developed to form collaborative robots for enabling wider applications.
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Affiliation(s)
- Yue Chen
- College of Mechanical and Electrical Engineering, Soochow University, Suzhou, 215000, China.
| | - Xuanhan Chen
- College of Mechanical and Electrical Engineering, Soochow University, Suzhou, 215000, China.
| | - Zhenhong Zhu
- Children's Hospital of Soochow University, Soochow University, Suzhou, 215000, China
| | - Mingyuan Sun
- College of Mechanical and Electrical Engineering, Soochow University, Suzhou, 215000, China.
| | - Shen Li
- College of Mechanical and Electrical Engineering, Soochow University, Suzhou, 215000, China.
| | - Minfeng Gan
- Department of Orthopedic, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou, 215000, China.
| | - Shi-Yang Tang
- Department of Electronic, Electrical and Systems Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Weihua Li
- School of Mechanical, Materials, Mechatronic and Biomedical Engineering, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Shiwu Zhang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, 230026, China
| | - Lining Sun
- College of Mechanical and Electrical Engineering, Soochow University, Suzhou, 215000, China.
| | - Xiangpeng Li
- College of Mechanical and Electrical Engineering, Soochow University, Suzhou, 215000, China.
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