1
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Li M, Guo Q, Wen J, Zhan F, Shi M, Zhou N, Huang C, Wang L, Mao H. Oriented bouncing of droplets with a small Weber number on inclined one-dimensional nanoforests. NANOSCALE 2024; 16:5343-5351. [PMID: 38375552 DOI: 10.1039/d3nr05449g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
Asymmetric superhydrophobic structures with anisotropic wettability can achieve directional bouncing of droplets and thus can have applications in directional self-cleaning, liquid transportation, and heat transfer. To achieve convenient large-scale preparation of asymmetric superhydrophobic surfaces, inclined nanoforests are prepared in this work using a technique of competitive ablation polymerization, which allows the control of the inclined angles, diameters, and heights of the nanostructures. In this study, such asymmetric structures with the smallest dimension (230 nm diameter) known are achieved by a simple etching method to guide droplet unidirectional bouncing. With such nanoforests, the mechanism of droplet bouncing on their surface is investigated, and controllable droplet bouncing over a long distance is achieved using droplets with a low Weber number. The proposed structure has a promising future in directional self-cleaning, liquid transportation and heat transfer.
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Affiliation(s)
- Mao Li
- Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029, P. R. China.
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Qiming Guo
- Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029, P. R. China.
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Jing Wen
- Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029, P. R. China.
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Fei Zhan
- Beijing Key Laboratory of Lignocellulosic Chemistry, MOE Engineering Research Center of Forestry Biomass Materials and Bioenergy, Beijing Forestry University, Beijing, 100083, China.
| | - Meng Shi
- Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029, P. R. China.
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Na Zhou
- Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029, P. R. China.
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Chengjun Huang
- Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029, P. R. China.
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Lei Wang
- Beijing Key Laboratory of Lignocellulosic Chemistry, MOE Engineering Research Center of Forestry Biomass Materials and Bioenergy, Beijing Forestry University, Beijing, 100083, China.
| | - Haiyang Mao
- Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029, P. R. China.
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
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2
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Hou L, Liu X, Ge X, Hu R, Cui Z, Wang N, Zhao Y. Designing of anisotropic gradient surfaces for directional liquid transport: Fundamentals, construction, and applications. Innovation (N Y) 2023; 4:100508. [PMID: 37753526 PMCID: PMC10518492 DOI: 10.1016/j.xinn.2023.100508] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 09/01/2023] [Indexed: 09/28/2023] Open
Abstract
Many biological surfaces are capable of transporting liquids in a directional manner without energy consumption. Inspired by nature, constructing asymmetric gradient surfaces to achieve desired droplet transport, such as a liquid diode, brings an incredibly valuable and promising area of research with a wide range of applications. Enabled by advances in nanotechnology and manufacturing techniques, biomimetics has emerged as a promising avenue for engineering various types of anisotropic material system. Over the past few decades, this approach has yielded significant progress in both fundamental understanding and practical applications. Theoretical studies revealed that the heterogeneous composition and topography mainly govern the wetting mechanisms and dynamics behavior of droplets, including the interdisciplinary aspects of materials, chemistry, and physics. In this review, we provide a concise overview of various biological surfaces that exhibit anisotropic droplet transport. We discussed the theoretical foundations and mechanisms of droplet motion on designed surfaces and reviewed recent research advances in droplet directional transport on designed plane surfaces and Janus membranes. Such liquid-diode materials yield diverse promising applications, involving droplet collection, liquid separation and delivery, functional textiles, and biomedical applications. We also discuss the recent challenges and ongoing approaches to enhance the functionality and application performance of anisotropic materials.
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Affiliation(s)
- Lanlan Hou
- Key Laboratory of Bioinspired Smart Interfacial Science and Technology of Ministry of Education, Beijing Key Laboratory of Bioinspired Energy Materials and Devices, School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
- School of Printing and Packaging Engineer, Beijing Institute of Graphic Communication, Beijing 102600, China
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiaofei Liu
- Key Laboratory of Bioinspired Smart Interfacial Science and Technology of Ministry of Education, Beijing Key Laboratory of Bioinspired Energy Materials and Devices, School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Xinran Ge
- Key Laboratory of Bioinspired Smart Interfacial Science and Technology of Ministry of Education, Beijing Key Laboratory of Bioinspired Energy Materials and Devices, School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Rongjun Hu
- Key Laboratory of Bioinspired Smart Interfacial Science and Technology of Ministry of Education, Beijing Key Laboratory of Bioinspired Energy Materials and Devices, School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
- Institute of Applied Chemistry, Jiangxi Academy of Sciences, Nanchang 330096, China
| | - Zhimin Cui
- Key Laboratory of Bioinspired Smart Interfacial Science and Technology of Ministry of Education, Beijing Key Laboratory of Bioinspired Energy Materials and Devices, School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Nü Wang
- Key Laboratory of Bioinspired Smart Interfacial Science and Technology of Ministry of Education, Beijing Key Laboratory of Bioinspired Energy Materials and Devices, School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Yong Zhao
- Key Laboratory of Bioinspired Smart Interfacial Science and Technology of Ministry of Education, Beijing Key Laboratory of Bioinspired Energy Materials and Devices, School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
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Liu X, Jia L, Dang C, Ding Y, Wang X. Directional Rebound of Microdroplets on a Magneto-Responsive Micropillar Array Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:15620-15629. [PMID: 37882503 DOI: 10.1021/acs.langmuir.3c01931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
The manipulation of droplet movement behavior is of scientific importance and has practical applications in many fields, such as biological analysis, water collection, oil-water separation, deicing, antifrosting, and so on. Using the magneto-responsive surface to dynamically change the surface morphology is an effective method to realize droplet manipulation. A replica molding technique was used to fabricate the surface with the magneto-responsive micropillar array, and the direction of the micropillar array could be changed dynamically with the magnetic induction intensity. The mechanism of the droplet directional rebound on the magneto-responsive surface and the implementation of the controllability of droplet movement were investigated. On the magneto-responsive surface, it was achievable to realize the directional rebound of droplets on the micrometer scale. The critical condition for the droplet directional rebound was identified. The force and energy of the droplet during the spreading and retraction stages were analyzed, which lay a theoretical foundation for the precise control of droplet directional rebound.
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Affiliation(s)
- Xinyuan Liu
- Beijing Key Laboratory of Flow and Heat Transfer of Phase Changing in Micro and Small Scale, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044, China
| | - Li Jia
- Beijing Key Laboratory of Flow and Heat Transfer of Phase Changing in Micro and Small Scale, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044, China
| | - Chao Dang
- Beijing Key Laboratory of Flow and Heat Transfer of Phase Changing in Micro and Small Scale, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044, China
| | - Yi Ding
- Beijing Key Laboratory of Flow and Heat Transfer of Phase Changing in Micro and Small Scale, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044, China
| | - Xiaowei Wang
- Beijing Key Laboratory of Flow and Heat Transfer of Phase Changing in Micro and Small Scale, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044, China
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4
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Liu X, Li B, Gu Z, Zhou K. 4D Printing of Butterfly Scale-Inspired Structures for Wide-Angle Directional Liquid Transport. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2207640. [PMID: 37078893 DOI: 10.1002/smll.202207640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Indexed: 05/03/2023]
Abstract
Unidirectional liquid transport has been extensively explored for water/fog harvesting, electrochemical sensing, and desalination. However, current research mainly focuses on linear liquid transport (transport angle α = 0°), which exhibits hindered lateral liquid spreading and low unidirectional transport efficiency. Inspired by the wide-angle (0° < α < 180°) liquid transport on butterfly wings, this work successfully achieves linear (α = 0°), wide-angle, and even ultra-wide-angle (α = 180°) liquid transport by four-dimensional (4D) printing of butterfly scale-inspired re-entrant structures. These asymmetric re-entrant structures can achieve unidirectional liquid transport, and their layout can control the Laplace pressure in the forward (structure-tilting) and lateral directions to adjust the transport angle. Specifically, high transport efficiency and programmable forward/lateral transport paths are simultaneously achieved by the ultra-wide-angle transport, where liquid fills the lateral path before being transported forward. Moreover, the ultra-wide-angle transport is also validated in 3D space, which provides an innovative platform for advanced biochemical microreaction, large-area evaporation, and self-propelled oil-water separation.
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Affiliation(s)
- Xiaojiang Liu
- Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, 639798, Singapore
- HP-NTU Digital Manufacturing Corporate Lab, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Boyuan Li
- Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Zhongze Gu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, China
| | - Kun Zhou
- Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, 639798, Singapore
- HP-NTU Digital Manufacturing Corporate Lab, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, 639798, Singapore
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5
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Du Y, Wu T, Li XL, Zhou WL, Ding C, Yang YQ, Wei JG, Lu X, Xie H, Qu JP. Efficient fabrication of tilt micro/nanopillars on polypropylene surface with robust superhydrophobicity for directional water droplet rebound. iScience 2022; 25:105107. [PMID: 36204271 PMCID: PMC9529960 DOI: 10.1016/j.isci.2022.105107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/24/2022] [Accepted: 09/07/2022] [Indexed: 10/29/2022] Open
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6
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Han X, Li J, Tang X, Li W, Zhao H, Yang L, Wang L. Droplet Bouncing: Fundamentals, Regulations, and Applications. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2200277. [PMID: 35306734 DOI: 10.1002/smll.202200277] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/13/2022] [Indexed: 06/14/2023]
Abstract
Droplet impact is a ubiquitous phenomenon in nature, daily life, and industrial processes. It is thus crucial to tune the impact outcomes for various applications. As a special outcome of droplet impact, the bouncing of droplets keeps the form of the droplets after the impact and minimizes the energy loss during the impact, being beneficial in many applications. A unified understanding of droplet bouncing is in high demand for effective development of new techniques to serve applications. This review shows the fundamentals, regulations, and applications of millimeter-sized droplet bouncing on solid surfaces and same/miscible liquids (liquid pool and another droplet). Regulation methods and current applications are summarized, and potential directions are proposed.
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Affiliation(s)
- Xing Han
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, 999077, Hong Kong
| | - Jiaqian Li
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, 999077, Hong Kong
| | - Xin Tang
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, 999077, Hong Kong
| | - Wei Li
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, 999077, Hong Kong
| | - Haibo Zhao
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, 999077, Hong Kong
- Department of Mechanics and Aerospace Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Ling Yang
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, 999077, Hong Kong
| | - Liqiu Wang
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, 999077, Hong Kong
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7
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Ni Y, Yuan C, Li S, Lu J, Yan L, Gu W, Xing W, Jing W. Temperature-induced hydrophobicity transition of MXene membrane for directly preparing W/O emulsions. Chin J Chem Eng 2022. [DOI: 10.1016/j.cjche.2022.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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8
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Liu C, Sun Y, Huanng J, Guo Z, Liu W. External-field-induced directional droplet transport: A review. Adv Colloid Interface Sci 2021; 295:102502. [PMID: 34390884 DOI: 10.1016/j.cis.2021.102502] [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: 06/02/2021] [Revised: 07/18/2021] [Accepted: 08/02/2021] [Indexed: 02/08/2023]
Abstract
Directional transport of fluids is crucial for vital activities of organisms and numerous industrial applications. This process has garnered widespread research attention due to the wide breadth of flexible applications such as medical diagnostics, drug delivery, and digital microfluidics. The rational design of functional surfaces that can achieve the subtle control of liquid behavior. Previous studies were mainly dependent on the special asymmetric structures, which inevitably have the problem of slow transport speed and short distance. To improve controllability, researchers have attempted to use external fields, such as thermal, light, electric fields, and magnetic fields, to achieve controllable droplet transport. On the fundamental side, much of their widespread applicably is due to the degree of control over droplet transport. This review provides an overview of recent progress in the last three years toward the transport of droplets with different mechanisms induced by various external stimuli, including light, electric, thermal, and magnetic field. First, the relevant basic theory and typical induced gradient for directional liquid transport are illustrated. We will then review the latest advances in the external-field-induced directional transport. Moreover, the most emerging applications such as digital microfluidics, harvesting of energy and water, heat transfer, and oil/water separation are also presented. Finally, we will outline possible future perspectives to attract more researchers interest and promote the development of this field.
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9
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Wei J, Xu X, Zhang J, Liu J. Measurement of Liquid Film Coverage on Vertical Plates with Hydrophilic and Structured Surface Treatments. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.0c05879] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Junqing Wei
- School of Electric Power, South China University of Technology, Guangzhou 510640, China
| | - Xiongwen Xu
- School of Electric Power, South China University of Technology, Guangzhou 510640, China
- Guangdong Province Key Laboratory of Efficient and Clean Energy Utilization, South China University of Technology, Guangzhou 510640, China
| | - Jia Zhang
- School of Electric Power, South China University of Technology, Guangzhou 510640, China
| | - Jinping Liu
- School of Electric Power, South China University of Technology, Guangzhou 510640, China
- State Key Laboratory of Subtropical Building Science, South China University of Technology, Guangzhou 510640, China
- Guangdong Province Key Laboratory of Efficient and Clean Energy Utilization, South China University of Technology, Guangzhou 510640, China
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10
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Zhang L, Zhao J, Xu J, Zhao J, Zhu Y, Li Y, You J. Switchable Isotropic/Anisotropic Wettability and Programmable Droplet Transportation on a Shape-Memory Honeycomb. ACS APPLIED MATERIALS & INTERFACES 2020; 12:42314-42320. [PMID: 32830490 DOI: 10.1021/acsami.0c11224] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Programmable droplet transportation is required urgently but is still challenging. In this work, breath figure was employed to fabricate shape-memory poly(lactic acid) (PLLA) honeycombs in which tiny crystals and an amorphous network act as the shape-fixed phase and recovery phase, respectively. Upon uniaxial tension, circle pores from the breath figure were deformed to elliptical pores, producing contact angle differences and anisotropic wetting behaviors in two directions. Both pore geometry and anisotropic wettability can be tailored via the draw ratio. On the PLLA honeycomb surface with a lower draw ratio, the contact angle difference is too small to induce droplet transportation along the desired direction. In the case of a higher draw ratio, however, the movement of water droplets has been controlled absolutely along the tension direction. The transition between them can be achieved reversibly during uniaxial tension and recovery processes based on the shape-memory effect. The enhanced flow control, which can be attributed to the synergism between optimal hydrophobicity and enlarged anisotropic wetting behaviors, endows water droplets with the ability to turn a corner spontaneously on a V-shaped surface including two regions exhibiting different oriented directions.
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Affiliation(s)
- Liang Zhang
- College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036, China
| | - Jingxin Zhao
- College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036, China
| | - Jinyan Xu
- College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036, China
| | - Jiaqin Zhao
- College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036, China
| | - Yutian Zhu
- College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036, China
| | - Yongjin Li
- College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036, China
| | - Jichun You
- College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036, China
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11
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Liu M, Li J, Zhou X, Li J, Feng S, Cheng Y, Wang S, Wang Z. Inhibiting Random Droplet Motion on Hot Surfaces by Engineering Symmetry-Breaking Janus-Mushroom Structure. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1907999. [PMID: 32078203 DOI: 10.1002/adma.201907999] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 02/08/2020] [Indexed: 06/10/2023]
Abstract
Concentrating impacting droplets onto a localized hotspot and inducing them to remain in a preferential heat transfer mode is essential for efficient thermal management such as spray cooling. Conventionally, droplets impacting on hot surfaces can randomly bounce off without becoming fully evaporated, resulting in low heat transfer efficiency. Although the directional and guided transport of impacting droplets to a preferential location can be achieved through the introduction of a structural gradient, the manifestation of such a motion requires the meticulous control of the spatial location where the droplet is released. Here, a novel surface consisting of regularly patterned posts with Janus-mushroom structure (JMS) is designed, in which the sidewalls of the individual posts are decorated with straight and curved morphologies. It is revealed that such structural symmetry-breaking in the individual posts leads to directional liquid penetration and vapor flow toward the straight sidewall, and also reduces the work of adhesion, altogether triggering collective and preferential droplet transport at a high temperature. By surrounding a conventional surface with JMS endowed with favorable directionality, it is possible to concentrate small impacting droplets preferentially onto a localized hotspot to achieve enhanced cooling efficiency.
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Affiliation(s)
- Minjie Liu
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, China
| | - Jing Li
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, China
| | - Xiaofeng Zhou
- Shanghai Key Laboratory of Multidimensional Information Processing, School of Communication and Electronic Engineering, East China Normal University, Shanghai, 200241, China
| | - Jiaqian Li
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, China
| | - Shile Feng
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, China
| | - Yaqi Cheng
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, China
| | - Steven Wang
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, China
| | - Zuankai Wang
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, China
- Shenzhen Research Institute of City University of Hong Kong, Shenzhen, 518057, China
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12
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Li J, Zhou X, Zhang Y, Hao C, Zhao F, Li M, Tang H, Ye W, Wang Z. Rectification of Mobile Leidenfrost Droplets by Planar Ratchets. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e1901751. [PMID: 31231945 DOI: 10.1002/smll.201901751] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 05/21/2019] [Indexed: 06/09/2023]
Abstract
The self-transportation of mobile Leidenfrost droplets with well-defined direction and velocity on millimetric ratchets is one of the most representative and spectacular phenomena in droplet dynamics. Despite extensive progress in the ability to control the spatiotemporal propagation of droplets, it remains elusive how the individual ratchet units, as well as the interactions within their arrays, are translated into the collective droplet dynamics. Here, simple planar ratchets characterized by uniform height normal to the surface are designed. It is revealed that on planar ratchets, the transport dynamics of Leidenfrost droplets is dependent not only on individual units, but also on the elegant coordination within their arrays dictated by their topography. The design of planar ratchets enriches the fundamental understanding of how the surface topography is translated into dynamic and collective droplet transport behaviors, and also imparts higher applicability in microelectromechanical system based fluidic devices.
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Affiliation(s)
- Jing Li
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, China
| | - Xiaofeng Zhou
- Department of Electronic Engineering, East China Normal University, Shanghai, 200241, China
| | - Yujie Zhang
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Hong Kong, 999077, China
| | - Chonglei Hao
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, China
| | - Fuwang Zhao
- Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hong Kong, 999077, China
| | - Minfei Li
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, China
| | - Hui Tang
- Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hong Kong, 999077, China
| | - Wenjing Ye
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Hong Kong, 999077, China
| | - Zuankai Wang
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, China
- Shenzhen Research Institute of City University of Hong Kong, Shenzhen, 518057, China
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13
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Li Z, Zhang D, Wang D, Zhang L, Feng L, Zhang X. A Bioinspired Flexible Film Fabricated by Surface-Tension-Assisted Replica Molding for Dynamic Control of Unidirectional Liquid Spreading. ACS APPLIED MATERIALS & INTERFACES 2019; 11:48505-48511. [PMID: 31790580 DOI: 10.1021/acsami.9b15385] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The unidirectional liquid spreading without external energy input has presently aroused widespread concern. Recently, on the peristome of Nepenthes alata, a novel 2D unidirectional liquid spreading has been reported. It has been revealed that its exquisite superhydrophilic multistage microstructure, overlapping microcavities with arc-shaped edges and wedge-shaped corners, is the main reason for this phenomenon. To fabricate a peristome-inspired surface, a replica molding method is highly efficient and provides an ideal structure. However, the curved shape of the finally formed surface cannot be adjusted, and a specific surface shows only one type of liquid spreading state, greatly limiting its potential application. Here, we aimed to develop a novel surface-tension-assisted replica molding method to fabricate an artificial peristome film. The artificial peristome film was fabricated by pouring styrenic block copolymers (SBS) dissolved in organic solvents into a negative replica prepared in polydimethylsiloxane (PDMS), based on the natural peristome. With volatilizing the organic solvent, the SBS agglomerates formed an artificial peristome film via surface tension effects. More importantly, the PDMS-negative replica swelled in the organic solvent and then returned to the original size, which is conducive for replicating microstructures. The liquid spreading speed could be dynamically controlled by stretching the artificial peristome film. We demonstrated that the microcavity wedge angle decreases with an increasing stretching ratio. A smaller wedge angle can result in a much stronger unidirectional liquid spreading ability. This study provides insight into the dynamic control of unidirectional liquid spreading for novel pump-free medical microfluidic devices.
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14
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Li J, Li J, Sun J, Feng S, Wang Z. Biological and Engineered Topological Droplet Rectifiers. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1806501. [PMID: 30697833 DOI: 10.1002/adma.201806501] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 11/18/2018] [Indexed: 06/09/2023]
Abstract
The power of the directional and spontaneous transport of liquid droplets is revealed through ubiquitous biological processes and numerous practical applications, where droplets are rectified to achieve preferential functions. Despite extensive progress, the fundamental understanding and the ability to exploit new strategies to rectify droplet transport remain elusive. Here, the latest progress in the fundamental understanding as well as the development of engineered droplet rectifiers that impart superior performance in a wide variety of working conditions, ranging from low temperature, ambient temperature, to high temperature, is discussed. For the first time, a phase diagram is formulated that naturally connects the droplet dynamics, including droplet formation modes, length scales, and phase states, with environmental conditions. Parallel approaches are then taken to discuss the basic physical mechanisms underlying biological droplet rectifiers, and a variety of strategies and manufacturing routes for the development of robust artificial droplet rectifiers. Finally, perspectives on how to create novel man-made rectifiers with functionalities beyond natural counterparts are presented.
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Affiliation(s)
- Jing Li
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, China
| | - Jiaqian Li
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, China
| | - Jing Sun
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, China
| | - Shile Feng
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, China
| | - Zuankai Wang
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, China
- Shenzhen Research Institute of City University of Hong Kong, Shenzhen, 518057, China
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15
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Li H, Fang W, Li Y, Yang Q, Li M, Li Q, Feng XQ, Song Y. Spontaneous droplets gyrating via asymmetric self-splitting on heterogeneous surfaces. Nat Commun 2019; 10:950. [PMID: 30837468 PMCID: PMC6401179 DOI: 10.1038/s41467-019-08919-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Accepted: 02/06/2019] [Indexed: 12/03/2022] Open
Abstract
Droplet impacting and bouncing off solid surface plays a vital role in various biological/physiological processes and engineering applications. However, due to a lack of accurate control of force transmission, the maneuver of the droplet movement and energy conversion is rather primitive. Here we show that the translational motion of an impacting droplet can be converted to gyration, with a maximum rotational speed exceeding 7300 revolutions per minute, through heterogeneous surface wettability regulation. The gyration behavior is enabled by the synergetic effect of the asymmetric pinning forces originated from surface heterogeneity and the excess surface energy of the spreading droplet after impact. The findings open a promising avenue for delicate control of liquid motion as well as actuating of solids. Controlling droplet impact and rebound behaviour can have applications in inkjet printing and self-cleaning. Here the authors show how a chemically-patterned surface with high-adhesive spirals surrounded by hydrophobic, low-adhesive regions leads to gyration behaviour of impacting droplets.
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Affiliation(s)
- Huizeng Li
- Key Laboratory of Green Printing, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, 100190, Beijing, P. R. China.,University of Chinese Academy of Sciences, 100049, Beijing, P. R. China
| | - Wei Fang
- AML, CNMM and Department of Engineering Mechanics, and State Key Laboratory of Tribology, Tsinghua University, 100084, Beijing, P. R. China
| | - Yanan Li
- Key Laboratory of Green Printing, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, 100190, Beijing, P. R. China
| | - Qiang Yang
- Key Laboratory of Green Printing, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, 100190, Beijing, P. R. China
| | - Mingzhu Li
- Key Laboratory of Green Printing, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, 100190, Beijing, P. R. China
| | - Qunyang Li
- AML, CNMM and Department of Engineering Mechanics, and State Key Laboratory of Tribology, Tsinghua University, 100084, Beijing, P. R. China
| | - Xi-Qiao Feng
- AML, CNMM and Department of Engineering Mechanics, and State Key Laboratory of Tribology, Tsinghua University, 100084, Beijing, P. R. China.
| | - Yanlin Song
- Key Laboratory of Green Printing, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, 100190, Beijing, P. R. China. .,University of Chinese Academy of Sciences, 100049, Beijing, P. R. China.
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16
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Liu J, Li S. Capillarity-driven migration of small objects: A critical review. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2019; 42:1. [PMID: 30612222 DOI: 10.1140/epje/i2019-11759-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Accepted: 11/30/2018] [Indexed: 06/09/2023]
Abstract
The phenomena on the capillarity-driven migration of small objects are full of interest for both scientific and engineering communities, and a critical review is thereby presented. The small objects mentioned here deal with the non-deformable objects, such as particles, rods, disks and metal sheets; and besides them, the soft objects are considered, such as droplets and bubbles. Two types of interfaces are analyzed, i.e., the solid-fluid interface and the fluid-fluid interface. Due to the easily deformable properties of the soft objects and distorted interfacial shapes induced by small objects, a more convenient way to obtain the driving force is through the potential energy of the system. The asymmetric factors causing the object migration include the asymmetric configuration of the interface, and the difference between the interfacial tensions. Finally, a simple outlook on the potential applications of small object migration is made. These behaviors may cast new light on the design of microfluidics and new devices, environment cleaning, oil and gas displacement and mineral industries.
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Affiliation(s)
- Jianlin Liu
- Department of Engineering Mechanics, College of Pipeline and Civil Engineering, China University of Petroleum (East China), 266580, Qingdao, China.
| | - Shanpeng Li
- Department of Engineering Mechanics, College of Pipeline and Civil Engineering, China University of Petroleum (East China), 266580, Qingdao, China
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17
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Wang Y, Wang R, Zhou Y, Huang Z, Wang J, Jiang L. Directional Droplet Propulsion on Gradient Boron Nitride Nanosheet Grid Surface Lubricated with a Vapor Film below the Leidenfrost Temperature. ACS NANO 2018; 12:11995-12003. [PMID: 30457835 DOI: 10.1021/acsnano.8b04039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Controlled propulsion of liquid droplets on a solid surface offers important applications in various fields, including fog harvesting, heat transfer, microfluidics, and microdevice technologies. The propulsion of the liquid droplet is realized only if the driven force exceeds the resistance force. Sometimes the directional propulsion of droplets only takes place at the Leidenfrost state to achieve enough lubrication for a vapor cushion. The thick vapor cushions levitate liquid droplets to reduce resistance force. However, it is still challenging to reduce the vapor cushion thickness and simultaneously realize the directional droplet's motion, especially below the Leidenfrost temperature. Here, a structurally hydrophobic boron nitride nanosheet (BNNS) grid surface was constructed with a two-direction topographical gradient, i. e., the perpendicular altitude gradient and the horizontal density gradient. The polar nature of the B-N bonds results in intrinsic hydrophilicity of the boron nitride layer, which increases the Leidenfrost point and facilitates wetting even at high temperature. Much thinner vapor-lubricating layers are competent in the droplet's directional motion below the Leidenfrost temperature of the BNNS grid surface because the air gap trapped within boron nitride nanosheet grids acts as a part of the lubrication layer.
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Affiliation(s)
- Yu Wang
- Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry , Beihang University , Beijing 100191 , China
- School of Materials Science and Engineering , Jiangxi University of Science and Technology , Ganzhou , Jiangxi 341000 , China
| | - Ruixiao Wang
- Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry , Beihang University , Beijing 100191 , China
| | - Yanjiao Zhou
- Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry , Beihang University , Beijing 100191 , China
| | - Zhenguo Huang
- Institute for Superconducting and Electronic Materials , University of Wollongong , Wollongong , New South Wales 2500 , Australia
| | - Jingming Wang
- Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry , Beihang University , Beijing 100191 , China
- Beijing Advanced Innovation Center for Biomedical Engineering , Beihang University , Beijing 100191 , China
| | - Lei Jiang
- Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry , Beihang University , Beijing 100191 , China
- Beijing Advanced Innovation Center for Biomedical Engineering , Beihang University , Beijing 100191 , China
- Laboratory of Bio-inspired Smart Interface Science, Technical Institute of Physics and Chemistry , Chinese Academy of Sciences , Beijing 100190 , China
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18
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Li H, Aili A, Alhosani MH, Ge Q, Zhang T. Directional Passive Transport of Microdroplets in Oil-Infused Diverging Channels for Effective Condensate Removal. ACS APPLIED MATERIALS & INTERFACES 2018; 10:20910-20919. [PMID: 29792417 DOI: 10.1021/acsami.8b00922] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Condensation widely exists in nature and industry, and its performance heavily relies on the efficiency of condensate removal. Recent advances in micro-/nanoscale surface engineering enable condensing droplet removal from solid surfaces without extra energy cost, but it is still challenging to achieve passive transport of microdroplets over long distances along horizontal surfaces. The mobility of these condensate droplets can be enhanced by lubricant oil infusion on flat surfaces and frequent coalescence, which lead to fast growth but random motion of droplets. In this work, we propose a novel design of diverging microchannels with oil-infused surfaces to achieve controllable, long-distance, and directional transport of condensing droplets on horizontal surfaces. This idea is experimentally demonstrated with diverging copper and silicon microchannels with nanoengineered surfaces. Along these hierarchical surface structures, microdroplets condense on the top channel wall and submerge into microchannels owing to the capillary pressure gradient in infusing oil. Confined by the microchannel walls, the submerged droplets deform and maintain the back-front curvature difference, which enables the motion of droplets along the channel diverging direction. Subsequent droplet coalescences inside the channel further enhance this directional transport. Moreover, fast-moving deformed droplets transfer their momentum to downstream spherical droplets through the infusing oil. As a result, simultaneous passive transport of multiple droplets (20-400 μm) is achieved over long distances (beyond 7 mm). On these oil-infused surfaces, satellite microdroplets can further nucleate and grow on an oil-cloaked droplet, demonstrating an enlarged surface area for condensation. Our findings on passive condensate removal offer great opportunities in condensation enhancement, self-cleaning, and other applications requiring directional droplet transport along horizontal surfaces.
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Affiliation(s)
- Hongxia Li
- Department of Mechanical and Materials Engineering , Masdar Institute, Khalifa University of Science and Technology , P.O. Box 54224, Abu Dhabi , UAE
| | - Ablimit Aili
- Department of Mechanical and Materials Engineering , Masdar Institute, Khalifa University of Science and Technology , P.O. Box 54224, Abu Dhabi , UAE
| | - Mohamed H Alhosani
- Department of Mechanical and Materials Engineering , Masdar Institute, Khalifa University of Science and Technology , P.O. Box 54224, Abu Dhabi , UAE
| | - Qiaoyu Ge
- Department of Mechanical and Materials Engineering , Masdar Institute, Khalifa University of Science and Technology , P.O. Box 54224, Abu Dhabi , UAE
| | - TieJun Zhang
- Department of Mechanical and Materials Engineering , Masdar Institute, Khalifa University of Science and Technology , P.O. Box 54224, Abu Dhabi , UAE
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19
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Gao F, Yao Y, Wang W, Wang X, Li L, Zhuang Q, Lin S. Light-Driven Transformation of Bio-Inspired Superhydrophobic Structure via Reconfigurable PAzoMA Microarrays: From Lotus Leaf to Rice Leaf. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b00059] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Fei Gao
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Yuan Yao
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Wei Wang
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Xiaofan Wang
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Lei Li
- College of Materials, Xiamen University, Xiamen 621005, China
| | - Qixin Zhuang
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Shaoliang Lin
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
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20
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Li Y, He L, Zhang X, Zhang N, Tian D. External-Field-Induced Gradient Wetting for Controllable Liquid Transport: From Movement on the Surface to Penetration into the Surface. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1703802. [PMID: 29052911 DOI: 10.1002/adma.201703802] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 09/02/2017] [Indexed: 06/07/2023]
Abstract
External-field-responsive liquid transport has received extensive research interest owing to its important applications in microfluidic devices, biological medical, liquid printing, separation, and so forth. To realize different levels of liquid transport on surfaces, the balance of the dynamic competing processes of gradient wetting and dewetting should be controlled to achieve good directionality, confined range, and selectivity of liquid wetting. Here, the recent progress in external-field-induced gradient wetting is summarized for controllable liquid transport from movement on the surface to penetration into the surface, particularly for liquid motion on, patterned wetting into, and permeation through films on superwetting surfaces with external field cooperation (e.g., light, electric fields, magnetic fields, temperature, pH, gas, solvent, and their combinations). The selected topics of external-field-induced liquid transport on the different levels of surfaces include directional liquid motion on the surface based on the wettability gradient under an external field, partial entry of a liquid into the surface to achieve patterned surface wettability for printing, and liquid-selective permeation of the film for separation. The future prospects of external-field-responsive liquid transport are also discussed.
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Affiliation(s)
- Yan Li
- Beijing Advanced Innovation Center for Biomedical Engineering, School of Chemistry, Beihang University, Beijing, 100191, P. R. China
| | - Linlin He
- Beijing Advanced Innovation Center for Biomedical Engineering, School of Chemistry, Beihang University, Beijing, 100191, P. R. China
| | - Xiaofang Zhang
- School of Mathematics and Physics, University of Science & Technology Beijing, Beijing, 100083, P. R. China
| | - Na Zhang
- Beijing Advanced Innovation Center for Biomedical Engineering, School of Chemistry, Beihang University, Beijing, 100191, P. R. China
| | - Dongliang Tian
- Beijing Advanced Innovation Center for Biomedical Engineering, School of Chemistry, Beihang University, Beijing, 100191, P. R. China
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21
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Self-propulsion of Leidenfrost Drops between Non-Parallel Structures. Sci Rep 2017; 7:12018. [PMID: 28931942 PMCID: PMC5607289 DOI: 10.1038/s41598-017-12279-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 09/07/2017] [Indexed: 11/09/2022] Open
Abstract
In this work, we explored self-propulsion of a Leidenfrost drop between non-parallel structures. A theoretical model was first developed to determine conditions for liquid drops to start moving away from the corner of two non-parallel plates. These conditions were then simplified for the case of a Leidenfrost drop. Furthermore, ejection speeds and travel distances of Leidenfrost drops were derived using a scaling law. Subsequently, the theoretical models were validated by experiments. Finally, three new devices have been developed to manipulate Leidenfrost drops in different ways.
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22
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Mrinal M, Wang X, Luo C. Self-Rotation-Induced Propulsion of a Leidenfrost Drop on a Ratchet. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:6307-6313. [PMID: 28582621 DOI: 10.1021/acs.langmuir.7b01420] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A Leidenfrost drop is capable of self-propelling on a ratchet, which consists of asymmetric teeth. In this work, the corresponding movements were first experimentally investigated. Because the detected motion could not be interpreted using existing propulsive mechanisms, a new propulsive mechanism was then developed, followed by force analysis using a scaling law.
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Affiliation(s)
- Manjarik Mrinal
- Department of Mechanical and Aerospace Engineering, University of Texas at Arlington , 500 W. First Street, Woolf Hall 226, Arlington, Texas 76019, United States
| | - Xiang Wang
- Department of Mechanical and Aerospace Engineering, University of Texas at Arlington , 500 W. First Street, Woolf Hall 226, Arlington, Texas 76019, United States
| | - Cheng Luo
- Department of Mechanical and Aerospace Engineering, University of Texas at Arlington , 500 W. First Street, Woolf Hall 226, Arlington, Texas 76019, United States
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23
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Zhong L, Guo Z. Effect of surface topography and wettability on the Leidenfrost effect. NANOSCALE 2017; 9:6219-6236. [PMID: 28470271 DOI: 10.1039/c7nr01845b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
When deposited on a superheated surface, a droplet can be levitated by its own vapour layer, a phenomenon that is referred to as the Leidenfrost effect. This dynamic effect has attracted interest for many potential applications, such as cooling, drag reduction and drop transport. A lot of effort has been paid to this mechanism over the past two and half centuries. Herein, we not only review the classical theories but also present the most recent theoretical advances in understanding the Leidenfrost effect. We first review the basic theories of the Leidenfrost effect, which mainly focuses on the relationship between the drop shape, vapour layer and lifetime. Then, the shift in the Leidenfrost point realized by fabricating special surface textures is introduced and the mechanisms behind this are analyzed. Furthermore, we present the reasons for the droplet transport in both classical Leidenfrost and pseudo-Leidenfrost regimes. Finally, the promising breakthroughs of the Leidenfrost effect are briefly addressed.
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Affiliation(s)
- Lieshuang Zhong
- Hubei Collaborative Innovation Centre for Advanced Organic Chemical Materials and Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei University, Wuhan 430062, People's Republic of China.
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24
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Li D, Feng S, Xing Y, Deng S, Zhou H, Zheng Y. Directional bouncing of droplets on oblique two-tier conical structures. RSC Adv 2017. [DOI: 10.1039/c7ra05820a] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The directional bouncing of droplets occurs on oblique two-tier conical structures, and the horizontal displacement is related to the oblique angle.
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Affiliation(s)
- Dan Li
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education
- School of Chemistry
- Beihang University
- Beijing
- P. R. China
| | - Shile Feng
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education
- School of Chemistry
- Beihang University
- Beijing
- P. R. China
| | - Yan Xing
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education
- School of Chemistry
- Beihang University
- Beijing
- P. R. China
| | - Siyan Deng
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education
- School of Chemistry
- Beihang University
- Beijing
- P. R. China
| | - Hu Zhou
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education
- School of Chemistry
- Beihang University
- Beijing
- 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
- P. R. China
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25
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Ionic imbalance induced self-propulsion of liquid metals. Nat Commun 2016; 7:12402. [PMID: 27488954 PMCID: PMC4976217 DOI: 10.1038/ncomms12402] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 06/29/2016] [Indexed: 12/19/2022] Open
Abstract
Components with self-propelling abilities are important building blocks of small autonomous systems and the characteristics of liquid metals are capable of fulfilling self-propulsion criteria. To date, there has been no exploration regarding the effect of electrolyte ionic content surrounding a liquid metal for symmetry breaking that generates motion. Here we show the controlled actuation of liquid metal droplets using only the ionic properties of the aqueous electrolyte. We demonstrate that pH or ionic concentration gradients across a liquid metal droplet induce both deformation and surface Marangoni flow. We show that the Lippmann dominated deformation results in maximum velocity for the self-propulsion of liquid metal droplets and illustrate several key applications, which take advantage of such electrolyte-induced motion. With this finding, it is possible to conceive the propulsion of small entities that are constructed and controlled entirely with fluids, progressing towards more advanced soft systems.
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26
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Li J, Hou Y, Liu Y, Hao C, Li M, Chaudhury MK, Yao S, Wang Z. Directional transport of high-temperature Janus droplets mediated by structural topography. NATURE PHYSICS 2016; 12:606-612. [DOI: 10.1038/nphys3643] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Accepted: 12/18/2015] [Indexed: 07/19/2023]
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27
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Hao C, Liu Y, Chen X, Li J, Zhang M, Zhao Y, Wang Z. Bioinspired Interfacial Materials with Enhanced Drop Mobility: From Fundamentals to Multifunctional Applications. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2016; 12:1825-1839. [PMID: 26865317 DOI: 10.1002/smll.201503060] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Revised: 11/19/2015] [Indexed: 06/05/2023]
Abstract
The development of bioinspired interfacial materials with enhanced drop mobility that mimic the innate functionalities of nature will have a significant impact on the energy, environment and global healthcare. Despite extensive progress, state of the art interfacial materials have not reached the level of maturity sufficient for industrial applications in terms of scalability, stability, and reliability. These are complicated by their operating environments and lack of facile approaches to control the local structural texture and chemical composition at multiple length scales. The recent advances in the fundamental understanding are reviewed, as well as practical applications of bioinspired interfacial materials, with an emphasis on the drop bouncing and coalescence-induced jumping behaviors. Perspectives on how to catalyze new discoveries and to foster technological adoption to move this exciting area forward are also suggested.
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Affiliation(s)
- Chonglei Hao
- Department of Mechanical and Biomedical Engineering, City University of Hong Kong, 999077, Hong Kong
| | - Yahua Liu
- Department of Mechanical and Biomedical Engineering, City University of Hong Kong, 999077, Hong Kong
| | - Xuemei Chen
- Department of Mechanical and Biomedical Engineering, City University of Hong Kong, 999077, Hong Kong
| | - Jing Li
- Department of Mechanical and Biomedical Engineering, City University of Hong Kong, 999077, Hong Kong
| | - Mei Zhang
- Department of Mechanical and Biomedical Engineering, City University of Hong Kong, 999077, Hong Kong
| | - Yanhua Zhao
- Department of Mechanical and Biomedical Engineering, City University of Hong Kong, 999077, Hong Kong
| | - Zuankai Wang
- Department of Mechanical and Biomedical Engineering, City University of Hong Kong, 999077, Hong Kong
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28
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Chen Y, Li D, Wang T, Zheng Y. Orientation-Induced Effects of Water Harvesting on Humps-on-Strings of Bioinspired Fibers. Sci Rep 2016; 6:19978. [PMID: 26812942 PMCID: PMC4728488 DOI: 10.1038/srep19978] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 12/09/2015] [Indexed: 11/08/2022] Open
Abstract
Smart water-collecting functions are naturally endowed on biological surfaces with unique wettable microstructures, e.g., beetle back with "alternate hydrophobic, hydrophilic micro-regions", and spider silk with wet-rebuilt "spindle-knot, joint" structures. Enlightened by the creature features, design of bio-inspired surfaces becomes the active issue in need of human beings for fresh water resource. Recently, as observed from spider web in nature, the net of spider silk is usually set in different situations and slopes in air, thus spider silks can be placed in all kinds of orientations as capturing water. Here, we show the styles and orientations of hump-on-string to control the ability of water collection as bioinspired silks are fabricated successfully. As different strings, sizes (height, length, pitch) of humps can become the controlling on volumes of extreme water drops. It is related to the different solid/liquid contact regions resulting in the as-modulated wet adhesion due to orientations of humps-on-strings. The conversion of high-low adhesion can be achieved to rely on orientations for the effect of capturing water drops. These studies offer an insight into enhancement of water collection efficiency and are helpful to design smart materials for controlled water drop capture and release via conversions of high-low adhesion.
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Affiliation(s)
- Yuan Chen
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing, 100191 (P. R. China)
| | - Dan Li
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing, 100191 (P. R. China)
| | - Ting Wang
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing, 100191 (P. R. China)
| | - Yongmei Zheng
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing, 100191 (P. R. China)
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29
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Su B, Tian Y, Jiang L. Bioinspired Interfaces with Superwettability: From Materials to Chemistry. J Am Chem Soc 2016; 138:1727-48. [DOI: 10.1021/jacs.5b12728] [Citation(s) in RCA: 790] [Impact Index Per Article: 98.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Bin Su
- Department
of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Ye Tian
- Beijing
National Laboratory for Molecular Sciences, Key Laboratory of Organic
Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
| | - Lei Jiang
- Laboratory
of Bioinspired Smart Interfacial Science, Technical Institute of Physics
and Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
- School
of Chemistry and Environment, Beihang University, Beijing 100191, P. R. China
- Department
of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia
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30
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Kim GH, Lee BH, Im H, Jeon SB, Kim D, Seol ML, Hwang H, Choi YK. Controlled anisotropic wetting of scalloped silicon nanogroove. RSC Adv 2016. [DOI: 10.1039/c6ra06379a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The anisotropic wetting characteristics of SNGs were investigated in dynamic and static regimes. The anisotropic wettability of the SNGs was successfully employed to control fluid flows in microfluidic channels.
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Affiliation(s)
- Gun-Hee Kim
- School of Electrical Engineering
- KAIST
- Daejeon 34141
- Republic of Korea
| | - Byung-Hyun Lee
- School of Electrical Engineering
- KAIST
- Daejeon 34141
- Republic of Korea
| | - Hwon Im
- School of Electrical Engineering
- KAIST
- Daejeon 34141
- Republic of Korea
| | - Seung-Bae Jeon
- School of Electrical Engineering
- KAIST
- Daejeon 34141
- Republic of Korea
| | - Daewon Kim
- School of Electrical Engineering
- KAIST
- Daejeon 34141
- Republic of Korea
| | - Myeong-Lok Seol
- School of Electrical Engineering
- KAIST
- Daejeon 34141
- Republic of Korea
| | - Hyundoo Hwang
- School of Engineering and Sciences
- Tecnológico de Monterrey
- Monterrey
- Mexico
| | - Yang-Kyu Choi
- School of Electrical Engineering
- KAIST
- Daejeon 34141
- Republic of Korea
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Mohammed M, Sundaresan R, Dickey MD. Self-Running Liquid Metal Drops that Delaminate Metal Films at Record Velocities. ACS APPLIED MATERIALS & INTERFACES 2015; 7:23163-23171. [PMID: 26423030 DOI: 10.1021/acsami.5b06978] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
This paper describes a new method to spontaneously accelerate droplets of liquid metal (eutectic gallium indium, EGaIn) to extremely fast velocities through a liquid medium and along predefined metallic paths. The droplet wets a thin metal trace (a film ∼100 nm thick, ∼ 1 mm wide) and generates a force that simultaneously delaminates the trace from the substrate (enhanced by spontaneous electrochemical reactions) while accelerating the droplet along the trace. The formation of a surface oxide on EGaIn prevents it from moving, but the use of an acidic medium or application of a reducing bias to the trace continuously removes the oxide skin to enable motion. The trace ultimately provides a sacrificial pathway for the metal and provides a mm-scale mimic to the templates used to guide molecular motors found in biology (e.g., actin filaments). The liquid metal can accelerate along linear, curved and U-shaped traces as well as uphill on surfaces inclined by 30 degrees. The droplets can accelerate through a viscous medium up to 180 mm/sec which is almost double the highest reported speed for self-running liquid metal droplets. The actuation of microscale objects found in nature (e.g., cells, microorganisms) inspires new mechanisms, such as these, to manipulate small objects. Droplets that are metallic may find additional applications in reconfigurable circuits, optics, heat transfer elements, and transient electronic circuits; the paper demonstrates the latter.
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Affiliation(s)
- Mohammed Mohammed
- Department of Chemical and Biomolecular Engineering, North Carolina State University , 911 Partners Way, Raleigh, North Carolina 27695, United States
| | - Rishi Sundaresan
- Department of Chemical and Biomolecular Engineering, North Carolina State University , 911 Partners Way, Raleigh, North Carolina 27695, United States
| | - Michael D Dickey
- Department of Chemical and Biomolecular Engineering, North Carolina State University , 911 Partners Way, Raleigh, North Carolina 27695, United States
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