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Liu C, Hu J, Zhen G, Chen J, Chen H, Huang S, Liu Y. Droplet Interactions with Hot Surfaces: Boiling Modes, Leidenfrost Temperature, Dynamics, and Applications. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2025:e2501592. [PMID: 40317884 DOI: 10.1002/smll.202501592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2025] [Revised: 04/14/2025] [Indexed: 05/07/2025]
Abstract
The interaction of droplets with high-temperature solid surfaces is critical in processes like machining cooling and internal combustion engine operations. As surface temperature rises, droplets transition through distinct boiling regimes: film evaporation, contact boiling, transition boiling, and film boiling. In the film boiling regime, droplets are suspended on a vapor layer formed by their evaporation, known as the Leidenfrost effect, which occurs above the Leidenfrost point-the minimum temperature for this phenomenon. While the vapors layer impairs heat transfer by acting as an insulator, it also facilitates droplet mobility, enabling applications in fluid motion control and driving research interest in this area. This review provides a comprehensive overview of droplet interactions with heated surfaces. It begins with a classification of boiling regimes and the criteria defining them, followed by an analysis of factors influencing the Leidenfrost point, including surface properties, liquid characteristics, and external conditions. The motion behaviors of droplets on high-temperature structured surfaces such as horizontal transport, vertical detachment, and rotation are then explored. Finally, potential applications for controlling droplet behavior on hot surfaces are discussed, including enhanced heat transfer, self-cleaning, drag reduction, and energy conversion, while highlighting emerging directions for future research.
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Affiliation(s)
- Cong Liu
- School of Mechanical Engineering, Yanshan University, Qinhuangdao, 066000, China
| | - Jinming Hu
- School of Mechanical Engineering, Yanshan University, Qinhuangdao, 066000, China
| | - Guangwei Zhen
- School of Mechanical Engineering, Yanshan University, Qinhuangdao, 066000, China
| | - Jigang Chen
- School of Mechanical Engineering, Yanshan University, Qinhuangdao, 066000, China
| | - Hao Chen
- School of Mechanical Engineering, Yanshan University, Qinhuangdao, 066000, China
| | - Shuiquan Huang
- School of Mechanical Engineering, Yanshan University, Qinhuangdao, 066000, China
| | - Yahua Liu
- State Key Laboratory of High-performance Precision Manufacturing, Dalian University of Technology, Department of Anaesthesiology, Central Hospital of Dalian University of Technology, Dalian, 116033, China
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2
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Sun T, Yan Z, Xue L, Jiang Y, Wu S. Effect of Biomimetic Fish Scale Texture on Reciprocating Friction Pairs on Interfacial Lubricating Oil Transport. Biomimetics (Basel) 2025; 10:248. [PMID: 40277647 PMCID: PMC12024596 DOI: 10.3390/biomimetics10040248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2025] [Revised: 04/15/2025] [Accepted: 04/16/2025] [Indexed: 04/26/2025] Open
Abstract
Focusing on the difficulty of lubrication in the scavenging port area of a cylinder liner of an actual marine two-stroke diesel engine, the transportation of interface lubricating oil was studied. In this paper, a biomimetic fish scale texture composed of fan-shaped and arc-shaped curves is designed, and the numerical simulation model is established according to this texture. Through simulation research, the variation rules of pressure distribution, interfacial velocity, and outlet volume flow rate on the biomimetic fish scale texture surface at different velocities and temperatures are obtained. Moreover, the biomimetic fish scale texture is machined on the surface of a reciprocating friction pair by laser etching, and the oil transport speed of the interface is tested under different conditions. The results show that the existence of the biomimetic fish scale texture on the friction pair can effectively improve the pressure difference between interfaces during reciprocating motion. The pressure difference enhances the flow properties of interfacial lubricating oil, thereby improving its mass transport capacity. In addition, increasing the movement speed and oil temperature can increase the oil transport speed of interfacial lubricating oil. The results of the experiment suggest that, under continuous and discontinuous interface conditions, compared with a friction pair without texture, the improvement rate of the lubricating oil transport speed at the interface of the friction pair with the biomimetic fish scale texture can reach 40.7% and 69.1%, respectively.
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Affiliation(s)
- Tao Sun
- Marine Engineering College, Dalian Maritime University, Dalian 116026, China; (T.S.); (L.X.)
| | - Zhijun Yan
- Marine Engineering College, Dalian Maritime University, Dalian 116026, China; (T.S.); (L.X.)
| | - Lixia Xue
- Marine Engineering College, Dalian Maritime University, Dalian 116026, China; (T.S.); (L.X.)
| | - Yuanyuan Jiang
- Transportation Engineering College, Dalian Maritime University, Dalian 116026, China; (Y.J.); (S.W.)
| | - Shibo Wu
- Transportation Engineering College, Dalian Maritime University, Dalian 116026, China; (Y.J.); (S.W.)
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Li Y, Liu H, Huo L, Lei M, Lakhtakia A. Compositional-Asymmetry-Induced Transition of Directional Liquid Transport on Tilted and Janusian Nanohair Arrays. ACS APPLIED MATERIALS & INTERFACES 2025; 17:20418-20430. [PMID: 40099843 DOI: 10.1021/acsami.4c23088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/20/2025]
Abstract
Anisotropic wetting on certain surfaces endowed with structural asymmetry or compositional gradients commonly impedes the directional adjustment of liquid transport. We report here that directional liquid transport (DLT) against the tilt direction of nanohair and in the reverse direction was achieved on tilted-nanohair arrays (TNAs) and tilted-Janusian-nanohair arrays (TJNAs), respectively. Janusian compositional asymmetry on the surface of TJNAs was created by plasma polymer deposition on structurally asymmetric TNAs previously fabricated by Faraday-cage-assisted plasma nanotexturing. The structurally asymmetric TNAs led to DLT against the tilting direction due to the asymmetric wetting under the capillary imbibition between tilted nanohairs and the preferential coalescence of liquid against the tilt direction. The Janusian compositional asymmetry of TJNAs changing the capillarity imbibition condition between tilted nanohairs resulted in the transition of the liquid spreading direction along the tilt direction. The spreading direction along and against the tilt direction is predicted through a comprehensive analysis of the structural and compositional asymmetries of the TNAs and TJNAs.
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Affiliation(s)
- Yupeng Li
- Surface Engineering Laboratory, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China
| | - Haodong Liu
- Surface Engineering Laboratory, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China
| | - Lei Huo
- Surface Engineering Laboratory, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China
| | - Mingkai Lei
- Surface Engineering Laboratory, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China
| | - Akhlesh Lakhtakia
- NanoMM-Nanoengineered Metamaterials Group, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802, United States
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Dai Q, Du C, Huang W, Wang X. Regulation of Liquid Self-Transport Through Architectural-Thermal Coupling: Transitioning From Free Surfaces to Open Channels. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2025; 12:e2412483. [PMID: 39888291 PMCID: PMC12005752 DOI: 10.1002/advs.202412483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2024] [Revised: 12/15/2024] [Indexed: 02/01/2025]
Abstract
In this work, the regulation of liquid self-transport is achieved through architectural and thermal coupling, transitioning from free surfaces to open channels. Hierarchical structures inspired by the skin of a Texas horned lizard are designed, with the primary structure of wedged grooves and the secondary structure of capillary crura. This design enables advantages including long-distance self-transport, liquid storage and active reflux management on free surfaces, directional transportation, synthesis and detection of reagents in confined spaces, as well as controllable motion and enhanced heat dissipation in open channels. The regulation capacity can be precisely controlled by adjusting the secondary capillary crura and external thermal gradients. The regulation mechanism is further elucidated through microscopic flow observation and a deduced theoretical model. The proposed structures are expected to introduce a new concept for designing lubrication systems, microfluidic chips, methods for chemical synthesis, and heat transfer in the future.
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Affiliation(s)
- Qingwen Dai
- National Key Laboratory of Helicopter AeromechanicsNanjing University of Aeronautics & AstronauticsNanjing210016China
- College of Mechanical and Electrical EngineeringNanjing University of Aeronautics & AstronauticsNanjing210016China
| | - Chengxuan Du
- National Key Laboratory of Helicopter AeromechanicsNanjing University of Aeronautics & AstronauticsNanjing210016China
- College of Mechanical and Electrical EngineeringNanjing University of Aeronautics & AstronauticsNanjing210016China
| | - Wei Huang
- National Key Laboratory of Helicopter AeromechanicsNanjing University of Aeronautics & AstronauticsNanjing210016China
- College of Mechanical and Electrical EngineeringNanjing University of Aeronautics & AstronauticsNanjing210016China
| | - Xiaolei Wang
- National Key Laboratory of Helicopter AeromechanicsNanjing University of Aeronautics & AstronauticsNanjing210016China
- College of Mechanical and Electrical EngineeringNanjing University of Aeronautics & AstronauticsNanjing210016China
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5
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Cha H, Kim MK, Chang HC, Zhang L, Miljkovic N. Pinning-Induced Microdroplet Self-Transport. ACS NANO 2025; 19:11049-11057. [PMID: 40079899 DOI: 10.1021/acsnano.4c16960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/15/2025]
Abstract
Droplets are prone to adhere or "pin" on solid surfaces which contain unavoidable micro- and nanoscale surface defects formed through chemical and topographical heterogeneity. To initiate droplet motion, potential energy gradients, surface energy gradients, or external energy input are needed. Here, in contrast to established wisdom, we show that properly designed surface heterogeneity can promote microdroplet self-transport without any external force or anisotropy. In the presence of topological defects, microdroplets can take advantage of contact line pinning to generate contact line and corresponding contact angle asymmetry, leading to spontaneous motion over distances 10-20 times larger than the droplet radius. The outcomes of this work present an alternative pathway for taking advantage of intrinsic surface heterogeneity to achieve droplet mobility in a range of applications, where passive droplet motion is desired.
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Affiliation(s)
- Hyeongyun Cha
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
- International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Moon-Kyung Kim
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Ho Chan Chang
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Lenan Zhang
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Nenad Miljkovic
- Department of Mechanical Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Electrical and Computer Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
- Materials Research Laboratory, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
- Institute for Sustainability, Energy and Environment (iSEE), University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
- Air Conditioning and Refrigeration Center, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
- International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
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Bai H, Zhao T, Cao M. Interfacial fluid manipulation with bioinspired strategies: special wettability and asymmetric structures. Chem Soc Rev 2025; 54:1733-1784. [PMID: 39745100 DOI: 10.1039/d4cs01073f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2025]
Abstract
The inspirations from nature always enlighten us to develop advanced science and technology. To survive in complicated and harsh environments, plants and animals have evolved remarkable capabilities to control fluid transfer via sophisticated designs such as wettability contrast, oriented micro-/nano-structures, and geometry gradients. Based on the bioinspired structures, the on-surface fluid manipulation exhibits spontaneous, continuous, smart, and integrated performances, which can promote the applications in the fields of heat transfer, microfluidics, heterogeneous catalysis, water harvesting, etc. Although fluid manipulating interfaces (FMIs) have provided plenty of ideas to optimize the current systems, a comprehensive review of history, classification, fabrication, and integration focusing on their interfacial chemistry and asymmetric structure is highly required. In this review, we systematically introduce development and highlight the state-of-the-art progress of bioinspired FMIs. Firstly, the biological prototype and development timeline are presented, and the underlying mechanism of on-surface fluid control on versatile structures is analyzed. Secondly, the definition and classification of FMIs as well as the strategy for controlling fluid/interface interaction are discussed. Thirdly, emergent applications of FMIs in practical scenarios including fog/vapor collection, fluid diodes, interfacial catalysis, etc. are presented. Furthermore, the challenges and prospects of interfacial liquid manipulation are concluded. We envision that this review should provide guidance for the incorporation of FMIs into suitable situations, which enlightens interdisciplinary research and practical applications in the fields of interface chemistry, materials design, bionic science, fluid dynamics, etc.
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Affiliation(s)
- Haoyu Bai
- School of materials science and engineering, Smart sensing interdisciplinary science center, Nankai university, Tianjin 300350, P. R. China.
| | - Tianhong Zhao
- School of materials science and engineering, Smart sensing interdisciplinary science center, Nankai university, Tianjin 300350, P. R. China.
| | - Moyuan Cao
- School of materials science and engineering, Smart sensing interdisciplinary science center, Nankai university, Tianjin 300350, P. R. China.
- Tianjin key laboratory of metal and molecule-based material chemistry, Nankai university, Tianjin 300192, P. R. China
- National institute for advanced materials, Nankai university, Tianjin 300350, P. R. China
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Li Z, Zhao R, Li T, Liu W, Liu Q, Fu M, Tang J, Wu W, Li H. Coalescence Mechanism Induced by Different Wetting States of Ti and Al Droplets on Rough Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:22835-22843. [PMID: 39431308 DOI: 10.1021/acs.langmuir.4c02841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2024]
Abstract
There is currently increasing interest in droplet transportation and coalescence on rough surfaces. However, the relationship among wettability, coalescence mode, and substrate characteristics (roughness and nanopillar height) remains unclear. In this work, two coalescence modes, climbing coalescence and contacting coalescence, are first observed in the dynamic behaviors of Ti and Al droplets on rough substrates. Due to the nonsynchronized wetting state transition of the droplets, the coalescence mode with increasing substrate characteristics differs, transitioning from contacting coalescence to climbing coalescence and then returning to the contacting mode. In general, the mode of coalescence correlates closely with the respective wetting states. Typically, Ti and Al droplets coalesce in the contacting mode when they have the same wetting state, but if they have different wetting states, they coalesce in the climbing mode. Our results emphasize the complicated relationship between the surface structure and the wettability of droplets, which could provide insights into self-assembly, three-dimensional printing, and microfluidic devices.
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Affiliation(s)
- Zhichao Li
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, China
| | - Ruopu Zhao
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, China
| | - Tao Li
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, China
- Department of Physics, Hong Kong University of Science and Technology, Kowloon 999077, Hong Kong, China
| | - Wenlong Liu
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, China
| | - Qingshui Liu
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, China
| | - Mengshuang Fu
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, China
| | - Jifeng Tang
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, China
| | - Weikang Wu
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, China
| | - Hui Li
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, China
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8
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Zhang T, Li M, Dong F, Huang F, Chuyo K, Wu J. Coalescence and Rebound Dynamics in Two Droplets Train Impacting on a Heterogeneous Wettability Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:22190-22201. [PMID: 39395012 DOI: 10.1021/acs.langmuir.4c02742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2024]
Abstract
Droplets that can be steered and rebound off surfaces are fundamentally interesting and important due to their promising potential in numerous applications, such as anti-icing and -fogging, spray coating, and self-cleaning. Heterogeneous wettability surfaces have been shown to be an effective means of droplet manipulation. This paper combines numerical simulation with theoretical analysis to investigate the dynamics of two droplets training impacting on and bouncing off a heterogeneous surface (superhydrophobic substrate decorated with a hydrophilic strip). First, the time evolutions of the droplet morphology and velocity vectors are examined to explore the particular dynamic behaviors. At different ratios of the impact velocity, three distinct rebound patterns are observed, and a regime diagram is established. After that, the effects of the impact conditions and surface wettability on the rebound performance of the coalesced droplet are studied systematically. Special attention is paid to the variations of the rebound height and the lateral transportation distance with the Weber number of two droplets and the distance between the impacting point and the hydrophilic stripe. Moreover, a theoretical analysis of two droplets' impact is performed based on the energy conservation. The obtained scaling laws match well with the numerical data in the trend. Our research may strengthen the understanding of the interactions between droplets, which is valuable for the manipulation of multiple droplets in related fields.
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Affiliation(s)
- Tongwei Zhang
- School of Automotive and Traffic Engineering, Jiangsu University, Zhenjiang 212013, China
- Key Laboratory of Unsteady Aerodynamics and Flow Control, Ministry of Industry and Information Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Meixuan Li
- Key Laboratory of Unsteady Aerodynamics and Flow Control, Ministry of Industry and Information Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Fei Dong
- School of Automotive and Traffic Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Fuxiang Huang
- School of Automotive and Traffic Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Kaku Chuyo
- R&D Center, Jiangsu Chaoli Electric Co. Ltd., Zhenjiang 212321, China
| | - Jie Wu
- Key Laboratory of Unsteady Aerodynamics and Flow Control, Ministry of Industry and Information Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
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Chen X, Yang G, Cao X, Zhu X, Wang X, Chen S, Cui Y, Ge H, Li Y. Bioinspired Hierarchical T Structures for Tunable Wettability and Droplet Manipulation by Facile and Scalable Nanoimprinting. ACS APPLIED MATERIALS & INTERFACES 2024; 16:54807-54817. [PMID: 39166707 DOI: 10.1021/acsami.4c10416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/23/2024]
Abstract
Developing surfaces that effectively repel low-surface-tension liquids with tunable adhesive properties remains a pivotal challenge. Micronano hierarchical re-entrant structures emerge as a promising solution, offering a robust structural defense against liquid penetration, minimizing area fraction, and creating narrow gaps that generate substantial upward Laplace pressure. However, the absence of an efficient, scalable, and tunable construction method has impeded their widespread applications. Here, drawing inspiration from springtail epidermal structures, octopus suckers, and rose petals, we present a scalable manufacturing strategy for artificial micronano hierarchical T-shaped structures. This strategy employs double-transfer UV-curing nanoimprint lithography to form nanostructures on microstructured surfaces, offering high structural tunability. This approach enables precise control over topography, feature size, and arrangement of nano- and microscale sections, resulting in superamphiphobic surfaces that exhibit high contact angles (>150°) and tunable adhesive forces for low-surface-energy liquids. These surfaces can be applied to droplet-based microreactors, programmable droplet-transfer systems, and self-cleaning surfaces suitable for various liquids, particularly those with low surface tension. Remarkably, we have also succeeded in fabricating the hierarchical structures on flexible and transparent substrates. We demonstrate the advantages of this strategy in the fabrication of hierarchical micronanostructures, opening up a wide range of potential applications.
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Affiliation(s)
- Xiaofeng Chen
- Department of Materials Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, P. R. China
- National Laboratory of Solid State Microstructures, Nanjing 210093, P. R. China
| | - Guiyan Yang
- Department of Materials Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, P. R. China
- National Laboratory of Solid State Microstructures, Nanjing 210093, P. R. China
| | - Xinhe Cao
- Department of Materials Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, P. R. China
- National Laboratory of Solid State Microstructures, Nanjing 210093, P. R. China
| | - Xinyue Zhu
- Department of Materials Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, P. R. China
- National Laboratory of Solid State Microstructures, Nanjing 210093, P. R. China
| | - Xinyu Wang
- Department of Materials Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, P. R. China
- National Laboratory of Solid State Microstructures, Nanjing 210093, P. R. China
| | - Si Chen
- Department of Materials Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, P. R. China
- National Laboratory of Solid State Microstructures, Nanjing 210093, P. R. China
| | - Yushuang Cui
- Department of Materials Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, P. R. China
- National Laboratory of Solid State Microstructures, Nanjing 210093, P. R. China
| | - Haixiong Ge
- Department of Materials Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, P. R. China
- National Laboratory of Solid State Microstructures, Nanjing 210093, P. R. China
| | - Yang Li
- College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009, Jiangsu, P. R. China
- State Key Laboratory of Materials-Orient Chemical Engineering, Nanjing Tech University, Nanjing 210009, Jiangsu, P. R. China
- Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites, Nanjing Tech University, Nanjing, Jiangsu 210009, P. R. China
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10
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Chae Y, Bae J, Kim T. Direct patterning of liquid materials on flat and curved substrates using flexible molds with through-hole and post arrays. RSC Adv 2024; 14:31217-31226. [PMID: 39355329 PMCID: PMC11443316 DOI: 10.1039/d4ra05252h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2024] [Accepted: 09/25/2024] [Indexed: 10/03/2024] Open
Abstract
Liquids undergo continuous deformation in the presence of external shear stresses; however, they are pinned between structures owing to their viscosity. Therefore, reshaping the liquids using their intrinsic material properties and structural interfaces is possible. In this study, we used the template-guided forming (TGF) method to reshape and produce oil patterns on flat and curved substrates. To produce oil patterns, we developed two oil patterning methods: direct heating-based oil patterning (DHOP) and solvent evaporation-based oil patterning (SEOP), which were characterized using various oils and solvents. To overcome the limitation of relying solely on liquid patterning that undergoes complete evaporation, we successfully fabricated liquid films using oil and nonpolar organic solvents that exhibit long-term stability. Therefore, achieving durability and control over the film thickness using nonpolar organic solvents has great potential for future applications in microfluidics. Furthermore, we demonstrated that the SEOP method in conjunction with TGF can produce various and unconventional patterns of an organic photoresist (SU-8), which cannot be produced through standard photolithography. Hence, we conclude that the proposed TFG-based oil pattering methods could be highly useful for producing unconventional and unprecedented patterns on flat and curved substrates for various applications, including microelectronics, optics, filtration and separation, biomedical engineering, and nanotechnology.
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Affiliation(s)
- Youngchul Chae
- Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST) 50 UNIST-gil Ulsan 44919 Republic of Korea +82-52-217-2409 +82-52-217-2313
| | - Juyeol Bae
- School of Mechanical Engineering, Chonnam National University 77 Yongbong-ro, Buk-gu Gwangju 61186 Republic of Korea
| | - Taesung Kim
- Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST) 50 UNIST-gil Ulsan 44919 Republic of Korea +82-52-217-2409 +82-52-217-2313
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST) 50 UNIST-gil Ulsan 44919 Republic of Korea
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11
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Josyula T, Kumar Malla L, Thomas TM, Kalichetty SS, Sinha Mahapatra P, Pattamatta A. Fundamentals and Applications of Surface Wetting. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:8293-8326. [PMID: 38587490 DOI: 10.1021/acs.langmuir.3c03339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
In an era defined by an insatiable thirst for sustainable energy solutions, responsible water management, and cutting-edge lab-on-a-chip diagnostics, surface wettability plays a pivotal role in these fields. The seamless integration of fundamental research and the following demonstration of applications on these groundbreaking technologies hinges on manipulating fluid through surface wettability, significantly optimizing performance, enhancing efficiency, and advancing overall sustainability. This Review explores the behavior of liquids when they engage with engineered surfaces, delving into the far-reaching implications of these interactions in various applications. Specifically, we explore surface wetting, dissecting it into three distinctive facets. First, we delve into the fundamental principles that underpin surface wetting. Next, we navigate the intricate liquid-surface interactions, unraveling the complex interplay of various fluid dynamics, as well as heat- and mass-transport mechanisms. Finally, we report on the practical realm, where we scrutinize the myriad applications of these principles in everyday processes and real-world scenarios.
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Affiliation(s)
- Tejaswi Josyula
- Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, India
| | - Laxman Kumar Malla
- School of Mechanical Sciences, Odisha University of Technology and Research, Bhubaneswar 751029, India
| | - Tibin M Thomas
- Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, India
| | | | - Pallab Sinha Mahapatra
- Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, India
| | - Arvind Pattamatta
- Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, India
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12
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Yang P, Yin K, Song X, Wang L, Deng Q, Pei J, He Y, Arnusch CJ. Airflow Triggered Water Film Self-Sculpturing on Femtosecond Laser-Induced Heterogeneously Wetted Micro/Nanostructured Surfaces. NANO LETTERS 2024; 24:3133-3141. [PMID: 38477056 DOI: 10.1021/acs.nanolett.3c05042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
Liquid manipulation is essential for daily life and modern industry, and it is widely used in various fields, including seawater desalination, microfluidic robots, and biomedical engineering. Nevertheless, the current research focuses on the manipulation of individual droplets. There are a few projects for water film management. Here, we proposed a facile method of wind-triggered water film self-sculpturing based on a heterogeneous wettability surface, which is achieved by the femtosecond laser direct writing technology and femtosecond laser deposition. Under the conditions of various airflow velocities and water film thicknesses, three distinct behaviors of the water film were analyzed. As a result, when the water film thickness is lower than 4.9 mm, the self-sculpture process will occur until the whole superhydrophobic surface dewetting. Four potential applications are demonstrated, including encryption, oil containers, reconfigurable patterning, and self-splitting devices. This work provides a new approach for manipulating a water film of fluid control engineering.
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Affiliation(s)
- Pengyu Yang
- Hunan Key Laboratory of Nanophotonics and Devices, School of Physics, Central South University, Changsha 410083, China
| | - Kai Yin
- Hunan Key Laboratory of Nanophotonics and Devices, School of Physics, Central South University, Changsha 410083, China
- The State Key Laboratory of High Performance and Complex Manufacturing, College of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China
| | - Xinghao Song
- Hunan Key Laboratory of Nanophotonics and Devices, School of Physics, Central South University, Changsha 410083, China
| | - Lingxiao Wang
- Hunan Key Laboratory of Nanophotonics and Devices, School of Physics, Central South University, Changsha 410083, China
| | - Qinwen Deng
- Hunan Key Laboratory of Nanophotonics and Devices, School of Physics, Central South University, Changsha 410083, China
| | - Jiaqing Pei
- Hunan Key Laboratory of Nanophotonics and Devices, School of Physics, Central South University, Changsha 410083, China
| | - Yuchun He
- Hunan Key Laboratory of Nanophotonics and Devices, School of Physics, Central South University, Changsha 410083, China
| | - Christopher J Arnusch
- Department of Desalination and Water Treatment, Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede-Boqer Campus, Midreshet Ben-Gurion 8499000, Israel
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13
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Huang Y, Wen G, Fan Y, He M, Sun W, Tian X, Huang S. Magnetic-Actuated Jumping of Droplets on Superhydrophobic Grooved Surfaces: A Versatile Strategy for Three-Dimensional Droplet Transportation. ACS NANO 2024; 18:6359-6372. [PMID: 38363638 DOI: 10.1021/acsnano.3c11197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
On-demand droplet transportation is of great significance for numerous applications. Although various strategies have been developed for droplet transportation, out-of-surface three-dimensional (3D) transportation of droplets remains challenging. Here, a versatile droplet transportation strategy based on magnetic-actuated jumping (MAJ) of droplets on superhydrophobic grooved surfaces (SHGSs) is presented, which enables 3D, remote, and precise manipulation of droplets even in enclosed narrow spaces. To trigger MAJ, an electromagnetic field is utilized to deform the droplet on the SHGS with the aid of an attached magnetic particle, thereby the droplet acquires excess surface energy. When the electromagnetic field is quickly removed, the excess surface energy is partly converted into kinetic energy, allowing the droplet to jump atop the surface. Through high-speed imaging and numerical simulation, the working mechanism and size matching effect of MAJ are unveiled. It is found that the MAJ behavior can only be observed if the sizes of the droplets and the superhydrophobic grooves are matched, otherwise unwanted entrapment or pinch-off effects would lead to failure of MAJ. A regime diagram which serves as a guideline to design SHGSs for MAJ is proposed. The droplet transportation capacities of MAJ, including in-surface and out-of-surface directional transportation, climbing stairs, and crossing obstacles, are also demonstrated. With the ability to remotely manipulate droplets in enclosed narrow spaces without using any mechanical moving parts, MAJ can be used to design miniaturized fluidic platforms, which exhibit great potential for applications in bioassays, microfluidics, droplet-based switches, and microreactions.
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Affiliation(s)
- Yusheng Huang
- School of Materials Science and Engineering, State Key Laboratory of Optoelectronic Materials and Technologies, Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, Sun Yat-sen University, Guangzhou 510006, China
| | - Guifeng Wen
- School of Materials Science and Engineering, State Key Laboratory of Optoelectronic Materials and Technologies, Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, Sun Yat-sen University, Guangzhou 510006, China
| | - Yue Fan
- School of Materials Science and Engineering, State Key Laboratory of Optoelectronic Materials and Technologies, Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, Sun Yat-sen University, Guangzhou 510006, China
| | - Maomao He
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Wen Sun
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Xuelin Tian
- School of Materials Science and Engineering, State Key Laboratory of Optoelectronic Materials and Technologies, Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, Sun Yat-sen University, Guangzhou 510006, China
| | - Shilin Huang
- School of Materials Science and Engineering, State Key Laboratory of Optoelectronic Materials and Technologies, Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, Sun Yat-sen University, Guangzhou 510006, China
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14
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Sun P, Hao X, Jin Y, Yin Y, Wu C, Zhang J, Gao L, Wang S, Wang Z. Heterogenous Slippery Surfaces: Enabling Spontaneous and Rapid Transport of Viscous Liquids with Viscosities Exceeding 10 000 mPa s. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2304218. [PMID: 37649201 DOI: 10.1002/smll.202304218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 08/07/2023] [Indexed: 09/01/2023]
Abstract
Superhydrophobic and slippery lubricant-infused surfaces have garnered significant attention for their potential to passively transport low-viscosity liquids like water (1 mPa s). Despite exciting progress, these designs have proven ineffective for transporting high-viscosity liquids such as polydimethylsiloxane (5500 mPa s) due to their inherent limitations imposed by the homogenous surface design, resulting in high viscous drags and compromised capillary forces. Here, a heterogenous water-infused divergent surface (WIDS) is proposed that achieves spontaneous, rapid, and long-distance transport of viscous liquids. WIDS reduces viscous drag by spatially isolating the viscous liquids and surface roughness through its heterogenous, slippery topological design, and generates capillary forces through its heterogenous wetting distributions. The essential role of surface heterogeneity in viscous liquid transport is theoretically and experimentally verified. Remarkably, such a heterogenous paradigm enables transporting liquids with viscosities exceeding 12 500 mPa s, which is two orders of magnitude higher than state-of-the-art techniques. Furthermore, this heterogenous design is generic for various viscous liquids and can be made flexible, making it promising for various systems that require viscous liquid management, such as micropatterning.
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Affiliation(s)
- Pengcheng Sun
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, P. R. China
| | - Xiuqing Hao
- Department of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu, 210000, P. R. China
| | - Yuankai Jin
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, P. R. China
| | - Yingying Yin
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, P. R. China
| | - Chenyang Wu
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, P. R. China
| | - Jie Zhang
- Department of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu, 210000, P. R. China
| | - Lujia Gao
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, P. R. China
| | - Steven Wang
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, 999077, P. R. China
| | - Zuankai Wang
- Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hong Kong, 999077, P. R. China
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15
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Zhang K, Xiang W, Liu J, Xie Z. Flexible droplet transportation and coalescence via controllable thermal fields. Anal Chim Acta 2023; 1277:341669. [PMID: 37604623 DOI: 10.1016/j.aca.2023.341669] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 07/03/2023] [Accepted: 07/26/2023] [Indexed: 08/23/2023]
Abstract
Flexible droplet transportation and coalescence are significant for lots of applications such as material synthesis and analytical detection. Herein, we present an effective method for controllable droplet transportation and coalescence via thermal fields. The device used for droplet manipulation is composed of a glass substrate with indium tin oxide-made microheaers and a microchannel with two transport branches and a central chamber, and it's manipulated by sequentially powering the microheaters located at the bottom of microchannel. The fluid will be unevenly heated when the microheater is actuated, leading to the formation of thermal buoyancy convection and the decrease of interfacial tension of fluids. Subsequently, the microdroplets can be transported from the inlets of microchannel to the target position by the buoyancy flow-induced Stokes drag. And the droplet migration velocity can be flexibly adjusted by changing the voltage applied on the microheater. After being transported to the center of central chamber, the coalescence behaviors of microdroplets can be triggered if the microheater located at the bottom of central chamber is continuously actuated. The droplet coalescence is the combined effect of decreased fluid interfacial tension, the shortened droplet distance by buoyancy flow and the increased instability of droplet under the elevated temperature. The droplet coalescence efficiency is also related to the voltage of microheater, by increasing the voltage from 3.5 V to 7 V, the needed time for droplet coalescence dramatically decrease from 220s to 1.4 s. Finally, by the droplet coalescence-triggered calcium hydroxide precipitation reaction, we demonstrate the applicability of the droplet manipulation method on specific sample detection. Therefore, this approach used for droplet transportation and coalescence can be attractive for many droplet-based applications such as analytical detection.
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Affiliation(s)
- Kailiang Zhang
- College of Mechanical and Electrical Engineering, Northeast Forestry University, Harbin, 150001, PR China
| | - Wei Xiang
- College of Mechanical and Electrical Engineering, Northeast Forestry University, Harbin, 150001, PR China
| | - Jiuqing Liu
- College of Mechanical and Electrical Engineering, Northeast Forestry University, Harbin, 150001, PR China
| | - Zhijie Xie
- College of Mechanical and Electrical Engineering, Northeast Forestry University, Harbin, 150001, PR China.
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16
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Hou H, Wu X, Hu Z, Gao S, Wu Y, Lin Y, Dai L, Zou G, Liu L, Yuan Z. High-speed directional transport of condensate droplets on superhydrophobic saw-tooth surfaces. J Colloid Interface Sci 2023; 649:290-301. [PMID: 37352560 DOI: 10.1016/j.jcis.2023.06.113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 06/12/2023] [Accepted: 06/16/2023] [Indexed: 06/25/2023]
Abstract
HYPOTHESIS Most droplets on high-efficiency condensing surfaces have radii of less than 100 μm, but conventional droplet transport methods (such as wettability-gradient surfaces and structural-curvature-gradient surfaces) that rely on the unbalanced force of three-phase lines can only transport millimeter-sized droplets efficiently. Regulating high-speed directional transport of condensate droplets is still challenging. Therefore, we present a method for condensate droplet transportation, based on the reaction force of the superhydrophobic saw-tooth surfaces to the liquid bridge, the condensate droplets could be transported at high speed and over long distances. EXPERIMENTS The superhydrophobic saw-tooth surfaces are fabricated by femtosecond laser ablation and chemical etching. Condensation experiments and luminescent particle characterization experiments on different surfaces are conducted. Aided by the theoretical analysis, we illustrate the remarkable performance of condensate droplet transportation on saw-tooth surfaces. FINDINGS Compared with conventional methods, our method improves the transport velocity and relative transport distance by 1-2 orders of magnitude and achieves directional transport of the smallest condensate droplet of about 2 μm. Furthermore, the superhydrophobic saw-tooth surfaces enable multi-hop directional jumping of condensate droplets, leading to cross-scale increases in transport distances from microns to decimeters.
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Affiliation(s)
- 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
| | - 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
| | - 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
| | - Yuxi Wu
- Department of Mechanical 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
| | - 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
| | - Guisheng Zou
- Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
| | - Lei Liu
- Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
| | - Zhiping Yuan
- Department of Energy and Power Engineering, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China.
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17
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Zeng Y, Khor JW, van Neel TL, Tu WC, Berthier J, Thongpang S, Berthier E, Theberge AB. Miniaturizing chemistry and biology using droplets in open systems. Nat Rev Chem 2023; 7:439-455. [PMID: 37117816 PMCID: PMC10107581 DOI: 10.1038/s41570-023-00483-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/24/2023] [Indexed: 04/30/2023]
Abstract
Open droplet microfluidic systems manipulate droplets on the picolitre-to-microlitre scale in an open environment. They combine the compartmentalization and control offered by traditional droplet-based microfluidics with the accessibility and ease-of-use of open microfluidics, bringing unique advantages to applications such as combinatorial reactions, droplet analysis and cell culture. Open systems provide direct access to droplets and allow on-demand droplet manipulation within the system without needing pumps or tubes, which makes the systems accessible to biologists without sophisticated setups. Furthermore, these systems can be produced with simple manufacturing and assembly steps that allow for manufacturing at scale and the translation of the method into clinical research. This Review introduces the different types of open droplet microfluidic system, presents the physical concepts leveraged by these systems and highlights key applications.
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Affiliation(s)
- Yuting Zeng
- Department of Chemistry, University of Washington, Seattle, WA, USA
| | - Jian Wei Khor
- Department of Chemistry, University of Washington, Seattle, WA, USA
| | - Tammi L van Neel
- Department of Chemistry, University of Washington, Seattle, WA, USA
| | - Wan-Chen Tu
- Department of Chemistry, University of Washington, Seattle, WA, USA
| | - Jean Berthier
- Department of Chemistry, University of Washington, Seattle, WA, USA
| | - Sanitta Thongpang
- Department of Chemistry, University of Washington, Seattle, WA, USA
- Department of Biomedical Engineering, Faculty of Engineering, Mahidol University, Nakorn Pathom, Thailand
| | - Erwin Berthier
- Department of Chemistry, University of Washington, Seattle, WA, USA.
| | - Ashleigh B Theberge
- Department of Chemistry, University of Washington, Seattle, WA, USA.
- Department of Urology, School of Medicine, University of Washington, Seattle, WA, USA.
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18
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Liu W, Lu Y, Shen Y, Chen H, Ni Y, Xu Y. Spontaneous Transport Mechanics of Water Droplets under a Synergistic Action of Designed Pattern and Non-Wetting Gradient. ACS OMEGA 2023; 8:16450-16458. [PMID: 37179628 PMCID: PMC10173426 DOI: 10.1021/acsomega.3c01536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 04/18/2023] [Indexed: 05/15/2023]
Abstract
The controllable spontaneous transport of water droplets on solid surfaces has a broad application background in daily life. Herein, a patterned surface with two different non-wetting characteristics was developed to control the droplet transport behavior. Consequently, the patterned surface exhibited great water-repellant properties in the superhydrophobic region, and the water contact angle reached 160° ± 0.2°. Meanwhile, the water contact angle on the wedge-shaped hydrophilic region dropped to 22° after UV irradiation treatment. On this basis, the maximum transport distance of water droplets could be observed on the sample surface with a small wedge angle of 5° (10.62 mm), and the maximum average transport velocity of droplets was obtained on the sample surface with a large wedge angle of 10° (218.01 mm/s). In terms of spontaneous droplet transport on an inclined surface (4°), both the 8 μL droplet and 50 μL droplet could move upward against gravity, which showed that the sample surface possessed an obvious driving force for droplet transport. Surface non-wetting gradient and the wedge-shaped pattern provided unbalanced surface tension to produce the driving forces in the process of droplet transport, and the Laplace pressure as well is produced inside the water droplet during this process. This work provides a new strategy to develop a patterned superhydrophobic surface for droplet transport.
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Affiliation(s)
- Weilan Liu
- Institute
of Advanced Materials (IAM), College of Materials Science and Engineering, Nanjing Tech University, 30 Puzhu South Road, Nanjing 211816, P. R. China
| | - Yang Lu
- Institute
of Advanced Materials (IAM), College of Materials Science and Engineering, Nanjing Tech University, 30 Puzhu South Road, Nanjing 211816, P. R. China
- College
of Materials Science and Technology, Nanjing
University of Aeronautics and Astronautics, Nanjing 211100, P. R. China
| | - Yizhou Shen
- Institute
of Advanced Materials (IAM), College of Materials Science and Engineering, Nanjing Tech University, 30 Puzhu South Road, Nanjing 211816, P. R. China
- College
of Materials Science and Technology, Nanjing
University of Aeronautics and Astronautics, Nanjing 211100, P. R. China
- . Phone: +86 25 52112911
| | - Haifeng Chen
- Department
of Materials Chemistry, Qiuzhen School, Huzhou University, 759#
East 2nd Road, Huzhou 313000, P. R. China
| | - Yaru Ni
- Institute
of Advanced Materials (IAM), College of Materials Science and Engineering, Nanjing Tech University, 30 Puzhu South Road, Nanjing 211816, P. R. China
- . Phone: +86 25 83587220
| | - Yangjiangshan Xu
- College
of Materials Science and Technology, Nanjing
University of Aeronautics and Astronautics, Nanjing 211100, P. R. China
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19
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Hao S, Xie Z, Yang W, Zhang L, Wang W, Kou J, Wu F, Fan J. Wetting-State-Induced Turning of Water Droplet Moving Direction on the Surface. ACS NANO 2023; 17:2182-2189. [PMID: 36728518 DOI: 10.1021/acsnano.2c08383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The spontaneous directional movement of water droplets on a wedge-shaped groove has gained extensive attention due to the advantage of not requiring energy input and its potential wide applications. However, manipulating the direction of movement of water droplets on a wedge-shaped groove has been not fully achieved, and the fundamental understanding of its underlying mechanism remains unclear. Here, molecular dynamics simulations and theoretical analyses are combined to reveal the mechanism of movement in opposite directions of a water droplet at the same position on the wedge-shaped groove interface. It is shown that the moving direction of the water droplet is related to its wetting state on the surface, i.e., the Wenzel and the Cassie states. A water droplet initially in the Wenzel and Cassie states will move toward the diverging and the converging ends, respectively. This phenomenon is attributed to the opposite roles played by the groove substrate and the upper layers in the two wetting states. Moreover, it is found that the water droplet is likely to move faster on a surface with a higher groove, larger opening angle and stronger hydrophobicity. These findings are expected to be of benefit for fully understanding droplet movement and shedding light on the regulation of the direction of movement of the droplets on the groove surface.
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Affiliation(s)
- Shaoqian Hao
- Institute of Condensed Matter Physics, Zhejiang Provincial Key Laboratory of Solid State Optoelectronic Devicces, and Zhejiang Institute of Photonelectronics, Zhejiang Normal University, Jinhua321004, China
- Institute of Theoretical Physics, State Key Laboratory of Quantum Optics and Quantum Optics Devices, Shanxi University, Taiyuan030006, China
| | - Zhang Xie
- Institute of Condensed Matter Physics, Zhejiang Provincial Key Laboratory of Solid State Optoelectronic Devicces, and Zhejiang Institute of Photonelectronics, Zhejiang Normal University, Jinhua321004, China
| | - Wenxin Yang
- School of Petroleum Engineering, China University of Petroleum (East China), Qingdao266580, China and
| | - Lei Zhang
- School of Petroleum Engineering, China University of Petroleum (East China), Qingdao266580, China and
| | - Wenyuan Wang
- Institute of Condensed Matter Physics, Zhejiang Provincial Key Laboratory of Solid State Optoelectronic Devicces, and Zhejiang Institute of Photonelectronics, Zhejiang Normal University, Jinhua321004, China
| | - Jianlong Kou
- Institute of Condensed Matter Physics, Zhejiang Provincial Key Laboratory of Solid State Optoelectronic Devicces, and Zhejiang Institute of Photonelectronics, Zhejiang Normal University, Jinhua321004, China
| | - Fengmin Wu
- Institute of Condensed Matter Physics, Zhejiang Provincial Key Laboratory of Solid State Optoelectronic Devicces, and Zhejiang Institute of Photonelectronics, Zhejiang Normal University, Jinhua321004, China
- Institute of Theoretical Physics, State Key Laboratory of Quantum Optics and Quantum Optics Devices, Shanxi University, Taiyuan030006, China
| | - Jintu Fan
- Department of Fiber Science and Apparel Design, Cornell University, Ithaca, New York14853-4401, United States
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20
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Abstract
Liquid-repellent surfaces, especially smooth solid surfaces with covalently grafted flexible polymer brushes or alkyl monolayers, are the focus of an expanding research area. Surface-tethered flexible species are highly mobile at room temperature, giving solid surfaces a unique liquid-like quality and unprecedented dynamical repellency towards various liquids regardless of their surface tension. Omniphobic liquid-like surfaces (LLSs) are a promising alternative to air-mediated superhydrophobic or superoleophobic surfaces and lubricant-mediated slippery surfaces, avoiding fabrication complexity and air/lubricant loss issues. More importantly, the liquid-like molecular layer controls many important interface properties, such as slip, friction and adhesion, which may enable novel functions and applications that are inaccessible with conventional solid coatings. In this Review, we introduce LLSs and their inherent dynamic omniphobic mechanisms. Particular emphasis is given to the fundamental principles of surface design and the consequences of the liquid-like nature for task-specific applications. We also provide an overview of the key challenges and opportunities for omniphobic LLSs.
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Affiliation(s)
- Liwei Chen
- School of Materials Science and Engineering, Key Laboratory for Polymer Composite & Functional Materials of Ministry of Education, Guangzhou Key Laboratory of Flexible Electronic Materials and Wearable Devices, Sun Yat-sen University, Guangzhou, P. R. China
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou, P. R. China
| | - Shilin Huang
- School of Materials Science and Engineering, Key Laboratory for Polymer Composite & Functional Materials of Ministry of Education, Guangzhou Key Laboratory of Flexible Electronic Materials and Wearable Devices, Sun Yat-sen University, Guangzhou, P. R. China
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou, P. R. China
| | - Robin H A Ras
- Department of Applied Physics, Aalto University School of Science, Espoo, Finland.
- Center of Excellence in Life-Inspired Hybrid Materials (LIBER), Aalto University, Espoo, Finland.
| | - Xuelin Tian
- School of Materials Science and Engineering, Key Laboratory for Polymer Composite & Functional Materials of Ministry of Education, Guangzhou Key Laboratory of Flexible Electronic Materials and Wearable Devices, Sun Yat-sen University, Guangzhou, P. R. China.
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou, P. R. China.
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21
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Wang F, Guo F, Wang Z, He H, Sun Y, Liang W, Yang B. Surface Charge Density Gradient Printing To Drive Droplet Transport: A Numerical Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:13697-13706. [PMID: 36317786 DOI: 10.1021/acs.langmuir.2c01772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Traditional strategies, such as morphological or chemical gradients, struggle to realize the high-velocity and long-distance transport for droplets on a solid surface because of the pinning hydrodynamic equilibrium. Thus, there is a continuing challenge for practical technology to drive droplet transport over the last decades. The surface charge density (SCD) gradient printing method overcame the theoretical limit of traditional strategies and tackled this challenge [Nat. Mater. 2019, 18: 936], which utilized the asymmetric electric force to realize the high-velocity and long-distance droplet transport along a preprinted SCD gradient pathway. In the present work, by coupling the electrostatics and the hydrodynamics, we developed an unexplored numerical model for the water droplet transporting along the charged superhydrophobic surface. Subsequently, the effects of SCD gradients on the droplet transport were systematically discussed, and an optimized method for SCD gradient printing was proposed according to the numerical results. The present approach can provide early guidance for the SCD gradient printing to drive droplet transport on a solid surface.
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Affiliation(s)
- Fangxin Wang
- College of Architectural Science and Engineering, Yangzhou University, Yangzhou225127, P.R. China
- College of Aerospace and Civil Engineering, Harbin Engineering University, Harbin150001, P.R. China
| | - Fuzheng Guo
- College of Architectural Science and Engineering, Yangzhou University, Yangzhou225127, P.R. China
| | - Zhenqing Wang
- College of Aerospace and Civil Engineering, Harbin Engineering University, Harbin150001, P.R. China
| | - Hailing He
- Department of Chemical Engineering, Tsinghua University, Beijing100084, P.R. China
| | - Yun Sun
- College of Architectural Science and Engineering, Yangzhou University, Yangzhou225127, P.R. China
| | - Wenyan Liang
- College of Aerospace and Civil Engineering, Harbin Engineering University, Harbin150001, P.R. China
| | - Bin Yang
- School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai200092, P.R. China
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22
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Zhang Q, Bai X, Li Y, Zhang X, Tian D, Jiang L. Ultrastable Super-Hydrophobic Surface with an Ordered Scaly Structure for Decompression and Guiding Liquid Manipulation. ACS NANO 2022; 16:16843-16852. [PMID: 36222751 DOI: 10.1021/acsnano.2c06749] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Directional droplet manipulation is very crucial in microfluidics, intelligent liquid management, etc. However, excessive liquid pressure tends to destroy the solid-gas-liquid (SAL) composite interface, creating a highly adhesive surface, which is not conducive to liquid transport. Herein, we propose a strategy to enhance the surface durability, in which the surface cannot withstand liquid pressure only by "blocking" but must instead guide liquid transport for "decompression". Learning from the water resistance of water strider legs and the drag reduction of shark skin, we present a continuous integrated system to obtain an ultrastable super-hydrophobic surface with a highly ordered scaly structure via a liquid flow-induced alignment method for lossless unidirectional liquid transport. The nonwetting scaly structure can both buffer liquid pressure and drive droplet motion to further reduce the vertical pressure of the liquid. Moreover, droplets can be manipulated unidirectionally using a voice. This work could aid in manufacturing scalable anisotropic micro-nanostructure surfaces, which inspires efforts in realizing lossless continuous liquid control on demand and related microfluidic applications.
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Affiliation(s)
- Qiuya Zhang
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology, School of Chemistry, Beihang University, Beijing100191, P. R. China
- School of Physics, Beihang University, Beijing100191, P. R. China
| | - Xiuhui Bai
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology, School of Chemistry, Beihang University, Beijing100191, P. R. China
| | - Yan Li
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology, School of Chemistry, Beihang University, Beijing100191, P. R. China
| | - Xiaofang Zhang
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing100083, P. R. China
| | - Dongliang Tian
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology, School of Chemistry, Beihang University, Beijing100191, P. R. China
- Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing100191, P. R. China
| | - Lei Jiang
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology, School of Chemistry, Beihang University, Beijing100191, P. R. China
- Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing100191, P. R. China
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing100191, P. R. China
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23
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Kang SM, An JH. Robust and Transparent Lossless Directional Omniphobic Ultra-Thin Sticker-Type Film with Re-entrant Micro-Stripe Arrays. ACS APPLIED MATERIALS & INTERFACES 2022; 14:39646-39653. [PMID: 35979700 DOI: 10.1021/acsami.2c12398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Directional droplet-sliding control without wetting the surface is immensely required in advanced surface engineering, including biological and chemical analyses or green technology. However, the development of robust and transparent thin sticker-type directional omniphobic films for portable usage in smart microfluidic platforms is rare. In this study, we report a novel perfluoropolyether (PFPE) directional omniphobic film (PDOF). The PDOF is a robust and transparent ultra-thin sticker-type film that can control the anisotropic sliding of various liquid droplets on the surface. The PFPE is a chemically stable and turgid material compared to polydimethylsiloxane (PDMS), which is often used to fabricate liquid-repellent thin films. A well-designed fabrication criterion through adhesion engineering in the soft-molding process was developed using the PFPE to obtain a PDOF with a thickness of 56 μm, with re-entrant micro-stripe structures on the surface. The fabricated PDOF showed intriguing liquid sliding properties based on the direction and spacing of the microstructures. This aspect is defined as an anisotropic factor.
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Affiliation(s)
- Seong Min Kang
- Department of Mechanical Engineering, Chungnam National University, Daejeon 34134, Korea
| | - Joon Hyung An
- Department of Mechanical Engineering, Chungnam National University, Daejeon 34134, Korea
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24
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Chu F, Yan X, Miljkovic N. How Superhydrophobic Grooves Drive Single-Droplet Jumping. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:4452-4460. [PMID: 35348343 DOI: 10.1021/acs.langmuir.2c00373] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Rapid shedding of microdroplets enhances the performance of self-cleaning, anti-icing, water-harvesting, and condensation heat-transfer surfaces. Coalescence-induced droplet jumping represents one of the most efficient microdroplet shedding approaches and is fundamentally limited by weak fluid-substrate dynamics, resulting in a departure velocity smaller than 0.3u, where u is the capillary-inertia-scaled droplet velocity. Laplace pressure-driven single-droplet jumping from rationally designed superhydrophobic grooves has been shown to break conventional capillary-inertia energy transfer paradigms by squeezing and launching single droplets independent of coalescence. However, this interesting droplet shedding mechanism remains poorly understood. Here, we investigate single-droplet jumping from superhydrophobic grooves by examining its dependence upon surface and droplet configurations. Using a volume of fluid (VOF) simulation framework benchmarked with optical visualizations, we verify the Laplace pressure contrast established within the groove-confined droplet that governs single-droplet jumping. An optimal departure velocity of 1.13u is achieved, well beyond what is currently available using condensation on homogeneous or hierarchical superhydrophobic structures. We further develop a jumping/non-jumping regime map in terms of surface wettability and initial droplet volume and demonstrate directional jumping under asymmetric confinement. Our work reveals key fluid-structure interactions required for the tuning of droplet jumping dynamics and guides the design of interfaces and materials for enhanced microdroplet shedding for a plethora of applications.
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Affiliation(s)
- Fuqiang Chu
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, People's Republic of China
| | - Xiao Yan
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Nenad Miljkovic
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
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25
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Xue J, Wu T, Qiu J, Xia Y. Accelerating Cell Migration along Radially Aligned Nanofibers through the Addition of Electrosprayed Nanoparticles in a Radial Density Gradient. PARTICLE & PARTICLE SYSTEMS CHARACTERIZATION : MEASUREMENT AND DESCRIPTION OF PARTICLE PROPERTIES AND BEHAVIOR IN POWDERS AND OTHER DISPERSE SYSTEMS 2022; 39:2100280. [PMID: 36091327 PMCID: PMC9455824 DOI: 10.1002/ppsc.202100280] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Scaffolds capable of promoting cell migration from the periphery towards the center along the radial direction hold promises for tissue regeneration. Here we report a simple and general method based on masked electrospray for the fabrication of such scaffolds by depositing collagen nanoparticles on radially-aligned nanofibers in a radial density gradient. Placed between the metallic needle and the collector, an aperture with tunable opening sizes serves as the mask. By increasing the size of the opening at a fixed speed, the electrosprayed particles take a radial density gradient that decreases from the center to the periphery. When deposited on a glass slide, the radial density gradient of collagen nanoparticles promotes the migration of fibroblasts from the periphery towards the center. By replacing the glass slide with a scaffold comprised of radially-aligned nanofibers, a synergetic effect arises to further accelerate cell migration along the radial direction. The synergistic effect can be attributed to a unique combination of the topographic cue arising from the aligned nanofibers and the haptotactic cue enabled by the graded nanoparticles. This work demonstrates a method to maximize cell migration from the periphery towards the center through a combination of topographic and haptotactic cues.
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Affiliation(s)
- Jiajia Xue
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, United States
| | - Tong Wu
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, United States
| | - Jichuan Qiu
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, United States
| | - Younan Xia
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, United States
- School of Chemistry and Biochemistry, School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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26
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Lee Y, Amberg G, Shiomi J. Vibration sorting of small droplets on hydrophilic surface by asymmetric contact-line friction. PNAS NEXUS 2022; 1:pgac027. [PMID: 36713314 PMCID: PMC9802364 DOI: 10.1093/pnasnexus/pgac027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 02/16/2022] [Accepted: 03/09/2022] [Indexed: 02/01/2023]
Abstract
Droplet spreading and transport phenomenon is ubiquitous and has been studied by engineered surfaces with a variety of topographic features. To obtain a directional bias in dynamic wetting, hydrophobic surfaces with a geometrical asymmetry are generally used, attributing the directionality to one-sided pinning. Although the pinning may be useful for directional wetting, it usually limits the droplet mobility, especially for small volumes and over wettable surfaces. Here, we demonstrate a pinning-less approach to rapidly transport millimeter sized droplets on a partially wetting surface. Placing droplets on an asymmetrically structured surfaces with micron-scale roughness and applying symmetric horizontal vibration, they travel rapidly in one direction without pinning. The key, here, is to generate capillary-driven rapid contact-line motion within the time-scale of period of vibration. At the right regime where a friction factor local at the contact line dominates the rapid capillary motion, the asymmetric surface geometry can induce smooth and continuous contact-line movement back and forth at different speed, realizing directional motion of droplets even with small volumes over the wettable surface. We found that the translational speed is selective and strongly dependent on the droplet volume, oscillation frequency, and surface pattern properties, and thus droplets with a specific volume can be efficiently sorted out.
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Affiliation(s)
- Yaerim Lee
- Department of Mechanical Engineering, The University of Tokyo, 7-3-1 Bunkyo-ku, Hongo, Tokyo 113-8656, Japan
| | - Gustav Amberg
- Department of Mechanics, Linné Flow Centre, The Royal Institute of Technology, SE-100 44 Stockholm, Sweden
- Södertörn University, Alfred Nobels allé 7, 141 89 Huddinge, Sweden
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27
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Roy T, Chaurasia SS, Cruz JM, Pimienta V, Parmananda P. Modes of synchrony in self-propelled pentanol drops. SOFT MATTER 2022; 18:1688-1695. [PMID: 35146497 DOI: 10.1039/d1sm01488a] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We report various modes of synchrony observed for a population of two, three and four pentanol drops in a rectangular channel at the air-water interface. Initially, the autonomous oscillations of a single 1-pentanol drop were studied in a ferroin DI water solution pre-mixed with some volume of pentanol. A pentanol drop performs continuous motion on the air-water interface due to Marangoni forces. A linear channel was prepared to study the uniaxial movement of the drop(s). Thereafter, a systematic study of the self-propelled motion of a 1-pentanol drop was reported as a function of the drop volume. Subsequently, the coupled dynamics were studied for two, three and four drops, respectively. We observed anti-phase oscillations in a pair of pentanol drops. In the case of three drops, relay synchronization was observed, wherein consecutive pairs of drops were exhibiting out-of-phase oscillations and alternate drops were performing in-phase oscillations. Four pentanol drops showed two different modes of synchrony: one was relay synchrony and the other was out-of-phase oscillations between two pairs of drops (within a pair, the drops exhibit in-phase oscillations).
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Affiliation(s)
- Tanushree Roy
- Department of Physics, IIT Bombay, Mumbai 400076, Maharashtra, India.
| | | | - José-Manuel Cruz
- Facultad de Ciencias en Física y Matemáticas, Universidad Autónoma de Chiapas, Tuxtla Gutiérrez, Chiapas 29050, Mexico
| | - V Pimienta
- Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, Université Paul Sabatier, 118 route de Narbonne 31062, Toulouse Cedex 9, France
| | - P Parmananda
- Department of Physics, IIT Bombay, Mumbai 400076, Maharashtra, India.
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28
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Lowrey S, Misiiuk K, Blaikie R, Sommers A. Survey of Micro/Nanofabricated Chemical, Topographical, and Compound Passive Wetting Gradient Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:605-619. [PMID: 34498455 DOI: 10.1021/acs.langmuir.1c00612] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Surface wetting gradients are desirable due to their ability to passively transport liquid droplets without the aid of gravity. Such surfaces can be prepared through topographical or chemical methods or a compound approach involving both methods. By altering the surface free energy across a surface, a droplet that contacts such a surface will experience an actuation force toward the hydrophilic region. Such transport properties make these surfaces attractive for a range of applications from thermal management to microfluidics to the investigation of biomolecular interactions. This paper reviews passive wetting gradients that have been demonstrated over the last three decades, focusing on the types of surfaces that have been developed to date along with the materials that have been used. The corresponding wetting ranges and physical lengths over which droplet mobility has been achieved on these various types of gradient surfaces are compared to guide future developments.
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Affiliation(s)
- Sam Lowrey
- Department of Physics, University of Otago, Dunedin 9016, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Wellington, Wellington 6012, New Zealand
| | - Kirill Misiiuk
- Department of Physics, University of Otago, Dunedin 9016, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Wellington, Wellington 6012, New Zealand
| | - Richard Blaikie
- Department of Physics, University of Otago, Dunedin 9016, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Wellington, Wellington 6012, New Zealand
| | - Andrew Sommers
- Department of Mechanical & Manufacturing Engineering, Miami University, Oxford, Ohio 45056, United States
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29
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Li Y, Zhang Q, Chen R, Yan Y, Sun Z, Zhang X, Tian D, Jiang L. Stretch-Enhanced Anisotropic Wetting on Transparent Elastomer Film for Controlled Liquid Transport. ACS NANO 2021; 15:19981-19989. [PMID: 34841855 DOI: 10.1021/acsnano.1c07512] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Direction-controlled wetting surfaces, special for lubricating oil infused anisotropic surfaces, have attracted great research interest in directional liquid collection, expelling, transfer, and separation. Nonetheless, there are still existing difficulties in achieving directional and continuous liquid transport. Herein, we present a strategy to achieve directional liquid transport on transparent lubricating oil infused elastomer film with V-shaped prisms microarray (VPM). The results reveal that the water wetting direction in the parallel and staggered arrangement of the VPM structure surface with lubricating oil infusion is the opposite, which is completely different from the wetting direction on the usual VPM surface in air. Moreover, asymmetric stretching can enhance or weaken the directional water wetting tendency on the lubricating oil infused VPM elastomer film and even can reverse the droplet wetting direction. In a closed moist environment, tiny droplets gradually coalesce and then slip away from the lubricating oil infused VPM surface to keep the surface transparent, due to the cooperation of imbalanced Laplace pressure, resulting from the anisotropic geometric structures, varying VPMs spacing, and gravity. Thus, this work provides a paradigm to design and fabricate a type of surface engineering material in the application fields of directional expelling, liquid collection, anti-biofouling, anti-icing, drag reduction, anticorrosion, etc.
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Affiliation(s)
- Yan Li
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, P. R. China
| | - Qiuya Zhang
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, P. R. China
| | - Rui Chen
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, P. R. China
| | - Yufeng Yan
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, P. R. China
| | - Zhenning Sun
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, P. R. China
| | - Xiaofang Zhang
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, P. R. China
| | - Dongliang Tian
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, P. R. China
- Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, P. R. China
| | - Lei Jiang
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, P. R. China
- Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, P. R. China
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100191, P. R. China
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30
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Tang Q, Liu X, Cui X, Su Z, Zheng H, Tang J, Joo SW. Contactless Discharge-Driven Droplet Motion on a Nonslippery Polymer Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:14697-14702. [PMID: 34894688 DOI: 10.1021/acs.langmuir.1c02462] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Droplet manipulation is the cornerstone of many modern technologies. It is still challenging to drive the droplet motion on nonslippery surfaces flexibly. We present a droplet manipulation method on nonslippery polymer surfaces based on the corona discharge. With the corona discharge of two-needle electrodes with opposite polarities, the droplet's charge polarity can be switched, which results in the directionally droplet transport on a charged polymer surface with the oscillation. Here, such droplet behaviors are presented in detail. Dependence of the motion on the critical distance and driving distance between the droplet and the needle electrode is revealed. The driving mechanism is verified by experiments and simulations. This work enriches the droplet manipulation techniques on nonslippery surfaces for various applications, such as combinatory chemistry, biochemical, and medical detection.
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Affiliation(s)
- Qiang Tang
- The Institute of Technological Sciences, Wuhan University, Wuhan 430072, China
| | - Xiaofeng Liu
- School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China
| | - Xiaxia Cui
- The Institute of Technological Sciences, Wuhan University, Wuhan 430072, China
| | - Zhenpeng Su
- School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China
| | - Huai Zheng
- The Institute of Technological Sciences, Wuhan University, Wuhan 430072, China
- School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China
| | - Jau Tang
- The Institute of Technological Sciences, Wuhan University, Wuhan 430072, China
| | - Sang Woo Joo
- School of Mechanical Engineering, Yeungnam University, Gyeongsan 38541, South Korea
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31
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Zhu P, Wang L. Microfluidics-Enabled Soft Manufacture of Materials with Tailorable Wettability. Chem Rev 2021; 122:7010-7060. [PMID: 34918913 DOI: 10.1021/acs.chemrev.1c00530] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Microfluidics and wettability are interrelated and mutually reinforcing fields, experiencing synergistic growth. Surface wettability is paramount in regulating microfluidic flows for processing and manipulating fluids at the microscale. Microfluidics, in turn, has emerged as a versatile platform for tailoring the wettability of materials. We present a critical review on the microfluidics-enabled soft manufacture (MESM) of materials with well-controlled wettability and their multidisciplinary applications. Microfluidics provides a variety of liquid templates for engineering materials with exquisite composition and morphology, laying the foundation for precisely controlling the wettability. Depending on the degree of ordering, liquid templates are divided into individual droplets, one-dimensional (1D) arrays, and two-dimensional (2D) or three-dimensional (3D) assemblies for the modular fabrication of microparticles, microfibers, and monolithic porous materials, respectively. Future exploration of MESM will enrich the diversity of chemical composition and physical structure for wettability control and thus markedly broaden the application horizons across engineering, physics, chemistry, biology, and medicine. This review aims to systematize this emerging yet robust technology, with the hope of aiding the realization of its full potential.
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Affiliation(s)
- Pingan Zhu
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, China
| | - Liqiu Wang
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
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32
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Programmable droplet manipulation and wetting with soft magnetic carpets. Proc Natl Acad Sci U S A 2021; 118:2111291118. [PMID: 34753822 PMCID: PMC8609634 DOI: 10.1073/pnas.2111291118] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2021] [Indexed: 12/20/2022] Open
Abstract
A set of magnetically responsive, soft hairs, which form a soft magnetic carpet, can be infused with a liquid to achieve switchable wetting. Applying a pattern of magnetic field results in a reconfigurable wetting pattern on the soft magnetic carpet. Combining this switchable wetting with a travelling magnetic field wave can allow us to spatially manipulate droplets. The efficiency of the droplet manipulation depends on the size and the contact angle of the droplet, which allows a pathway to sort and separate different droplets. Temporal and spatial control over multiple droplets allows us to conduct droplet reactions, which has a potential to be used for automated analytical testing and screening. The ability to regulate interfacial and wetting properties is highly demanded in anti-icing, anti-biofouling, and medical and energy applications. Recent work on liquid-infused systems achieved switching wetting properties, which allow us to turn between slip and pin states. However, patterning the wetting of surfaces in a dynamic fashion still remains a challenge. In this work, we use programmable wetting to activate and propel droplets over large distances. We achieve this with liquid-infused soft magnetic carpets (SMCs) that consist of pillars that are responsive to external magnetic stimuli. Liquid-infused SMCs, which are sticky for a water droplet, become slippery upon application of a magnetic field. Application of a patterned magnetic field results in a patterned wetting on the SMC. A traveling magnetic field wave translates the patterned wetting on the substrate, which allows droplet manipulation. The droplet speed increases with an increased contact angle and with the droplet size, which offers a potential method to sort and separate droplets with respect to their contact angle or size. Furthermore, programmable control of the droplet allows us to conduct reactions by combining droplets loaded with reagents. Such an ability of conducting small-scale reactions on SMCs has the potential to be used for automated analytical testing, diagnostics, and screening, with a potential to reduce the chemical waste.
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33
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Kumar DJP, Borkar C, Dayal P. Fast-Moving Self-Propelled Droplets of a Nanocatalyzed Belousov-Zhabotinsky Reaction. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:12586-12595. [PMID: 34670083 DOI: 10.1021/acs.langmuir.1c01887] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Self-sustained locomotion by virtue of an internalized chemical reaction is a characteristic feature of living systems and has inspired researchers to develop such self-moving biomimetic systems. Here, we harness a self-oscillating Belousov-Zhabotinsky (BZ) reaction, a well-known chemical oscillator, with enhanced kinetics by virtue of our graphene-based catalytic mats, to elucidate the spontaneous locomotion of BZ reaction droplets. Specifically, our nanocatalysts comprise ruthenium nanoparticle decorations on graphene oxide, reduced graphene oxide, and graphene nanosheets, thereby creating 0D-2D heterostructures. We demonstrate that when these nanocatalyzed droplets of the BZ reaction are placed in an oil-surfactant medium, they exhibit a macroscopic translatory motion at the velocities of few millimeters per second. This motion is brought about by the combination of enhanced kinetics of the BZ reaction and the Marangoni effect. Our investigations reveal that the velocity of locomotion increases with the electrical conductivity of our nanocomposites. Moreover, we also show that the positive feedback generated by the reaction-diffusion phenomena results in an asymmetric distribution of surface tension that, in turn, facilitates the self-propelled motion of the BZ droplets. Finally, we explore a system of multiple nanocatalyzed BZ droplets and reveal a variety of motions caused by their mutual interactions. Our findings suggest that through the use of 0D-2D hybrid nanomaterials, it is possible to design fast-moving self-propelled synthetic objects for a variety of biomimetic applications.
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Affiliation(s)
- D Jaya Prasanna Kumar
- Department of Chemical Engineering, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat 382355, India
| | - Chaitra Borkar
- Department of Chemical Engineering, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat 382355, India
| | - Pratyush Dayal
- Department of Chemical Engineering, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat 382355, India
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34
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Hu S, Reddyhoff T, Li J, Cao X, Shi X, Peng Z, deMello AJ, Dini D. Biomimetic Water-Repelling Surfaces with Robustly Flexible Structures. ACS APPLIED MATERIALS & INTERFACES 2021; 13:31310-31319. [PMID: 34171192 DOI: 10.1021/acsami.1c10157] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Biomimetic liquid-repelling surfaces have been the subject of considerable scientific research and technological application. To design such surfaces, a flexibility-based oscillation strategy has been shown to resolve the problem of liquid-surface positioning encountered by the previous, rigidity-based asymmetry strategy; however, its usage is limited by weak mechanical robustness and confined repellency enhancement. Here, we design a flexible surface comprising mesoscale heads and microscale spring sets, in analogy to the mushroomlike geometry discovered on springtail cuticles, and then realize this through three-dimensional projection microstereolithography. Such a surface exhibits strong mechanical robustness against ubiquitous normal and shear compression and even endures tribological friction. Simultaneously, the surface elevates water repellency for impacting droplets by enhancing impalement resistance and reducing contact time, partially reaching an improvement of ∼80% via structural tilting movements. This is the first demonstration of flexible interfacial structures to robustly endure tribological friction as well as to promote water repellency, approaching real-world applications of water repelling. Also, a flexibility gradient is created on the surface to directionally manipulate droplets, paving the way for droplet transport.
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Affiliation(s)
- Songtao Hu
- State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Tom Reddyhoff
- Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Jinbang Li
- School of Mechanical Engineering and Mechanics, Ningbo University, Ningbo 315211, China
| | - Xiaobao Cao
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich 8093, Switzerland
| | - Xi Shi
- State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhike Peng
- State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Andrew J deMello
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich 8093, Switzerland
| | - Daniele Dini
- Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, United Kingdom
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35
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Wang Z, Yang J, Dai X, Guo J, Li S, Sherazi TA, Zhang S. An integrated Janus porous membrane with controllable under-oil directional water transport and fluid gating property for oil/water emulsion separation. J Memb Sci 2021. [DOI: 10.1016/j.memsci.2021.119229] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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36
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Shrestha B, Ezazi M, Kwon G. Engineered Nanoparticles with Decoupled Photocatalysis and Wettability for Membrane-Based Desalination and Separation of Oil-Saline Water Mixtures. NANOMATERIALS 2021; 11:nano11061397. [PMID: 34070494 PMCID: PMC8227411 DOI: 10.3390/nano11061397] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 05/21/2021] [Accepted: 05/22/2021] [Indexed: 12/14/2022]
Abstract
Membrane-based separation technologies are the cornerstone of remediating unconventional water sources, including brackish and industrial or municipal wastewater, as they are relatively energy-efficient and versatile. However, membrane fouling by dissolved and suspended substances in the feed stream remains a primary challenge that currently prevents these membranes from being used in real practices. Thus, we directly address this challenge by applying a superhydrophilic and oleophobic coating to a commercial membrane surface which can be utilized to separate and desalinate an oil and saline water mixture, in addition to photocatalytically degrading the organic substances. We fabricated the photocatalytic membrane by coating a commercial membrane with an ultraviolet (UV) light-curable adhesive. Then, we sprayed it with a mixture of photocatalytic nitrogen-doped titania (N-TiO2) and perfluoro silane-grafted silica (F-SiO2) nanoparticles. The membrane was placed under a UV light, which resulted in a chemically heterogeneous surface with intercalating high and low surface energy regions (i.e., N-TiO2 and F-SiO2, respectively) that were securely bound to the commercial membrane surface. We demonstrated that the coated membrane could be utilized for continuous separation and desalination of an oil–saline water mixture and for simultaneous photocatalytic degradation of the organic substances adsorbed on the membrane surface upon visible light irradiation.
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Xiao X, Li S, Zhu X, Xiao X, Zhang C, Jiang F, Yu C, Jiang L. Bioinspired Two-Dimensional Structure with Asymmetric Wettability Barriers for Unidirectional and Long-Distance Gas Bubble Delivery Underwater. NANO LETTERS 2021; 21:2117-2123. [PMID: 33599507 DOI: 10.1021/acs.nanolett.0c04814] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Gas bubble manipulations in liquid have long been a concern because of their vital roles in various gas-related fields. To deal with the weakness in long-distance gas transportation of previous works, we took inspiration from the ridgelike structure on Nepenthes pitcher's peristome and successfully prepared a two-dimensional superaerophilic surface decorated with asymmetric aerophobic barriers capable of unidirectional and long-distance gas bubble delivery. For the first time, this process was investigated by in situ bubble-releasing experiments recorded by a high-speed camera and finite element modeling, which demonstrates a kinetic process regulated by the anisotropic motion resistance arising from the patterns. Furthermore, the Nepenthes alata-inspired two-dimensional surface (NATS) was integrated into a water electrolysis system for H2 directional transportation and efficient collection. As a result, the NATS design was proved to be a potential solution for facile manipulation of gas bubbles and provides a simple, adaptive, and reliable strategy for long-range gas transport underwater.
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Affiliation(s)
- Xiao Xiao
- Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, China
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Shukun Li
- Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, China
| | - Xiandong Zhu
- Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, China
| | - Xiao Xiao
- Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing 100191, China
| | - Chunhui Zhang
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fengmin Jiang
- Beijing Institute of Technology, Beijing 100080, China
| | - Cunming Yu
- Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, 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
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Zhu P, Chen C, Nandakumar K, Wang L. Nonspecular Reflection of Droplets. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2006695. [PMID: 33345437 DOI: 10.1002/smll.202006695] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Indexed: 06/12/2023]
Abstract
The bouncing of droplets on super-repellent surfaces normally resembles specular reflection that obeys the law of reflection. Here, the nonspecular reflection of droplet impingement onto solid surfaces with a dimple for energy-efficient, omnidirectional droplet transport is reported. With the dimple of the radius being comparable to that of the droplet, all the symmetries in the law of reflection can be broken down so that the droplet is endowed with a translational velocity finely tunable in both its direction and magnitude simply by varying the radii of the droplet and the dimple, the impinging position, and droplet Weber number. Tailoring the initial and translational velocity of impinging droplets would steer their reflected trajectories at will, thus enabling versatile droplet manipulation including trapping, shedding, antigravity transport, targeted positioning, and on-demand coalescence of droplets.
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Affiliation(s)
- Pingan Zhu
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, China
- HKU-Zhejiang Institute of Research and Innovation (HKU-ZIRI), Hangzhou, Zhejiang, 311300, China
| | - Chengmin Chen
- Energy Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, 250014, China
- School of Energy and Power Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, 250014, China
| | - Krishnaswamy Nandakumar
- Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Liqiu Wang
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
- HKU-Zhejiang Institute of Research and Innovation (HKU-ZIRI), Hangzhou, Zhejiang, 311300, China
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Soltani M, Golovin K. Anisotropy-induced directional self-transportation of low surface tension liquids: a review. RSC Adv 2020; 10:40569-40581. [PMID: 35520851 PMCID: PMC9057580 DOI: 10.1039/d0ra08627d] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 11/02/2020] [Indexed: 11/29/2022] Open
Abstract
Inspired by natural surfaces such as butterfly wings, cactus leaves, or the Nepenthes alata plant, synthetic materials may be engineered to directionally transport liquids on their surface without external energy input. This advantageous feature has been adopted for various mechanical and chemical processes, e.g. fog harvesting, lubrication, lossless chemical reactions, etc. Many studies have focused on the manipulation and transport of water or aqueous droplets, but significantly fewer have extended their work to low surface tension (LST) liquids, although these fluids are involved in numerous industrial and everyday processes. LST liquids completely wet most surfaces which makes spontaneous transportation an active challenge. This review focuses on recently developed strategies for passively and directionally transporting LST liquids.
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Affiliation(s)
- Mohammad Soltani
- Okanagan Polymer Engineering Research & Applications Laboratory, Faculty of Applied Science, University of British Columbia Canada
| | - Kevin Golovin
- Okanagan Polymer Engineering Research & Applications Laboratory, Faculty of Applied Science, University of British Columbia Canada
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Zhang Y, Gan Y, Zhang L, Zhang D, Chen H. Surface-Tension-Confined Channel with Biomimetic Microstructures for Unidirectional Liquid Spreading. MICROMACHINES 2020; 11:E978. [PMID: 33143205 PMCID: PMC7692703 DOI: 10.3390/mi11110978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 10/26/2020] [Accepted: 10/29/2020] [Indexed: 06/11/2023]
Abstract
Unidirectional liquid spreading without energy input is of significant interest for the broad applications in diverse fields such as water harvesting, drop transfer, oil-water separation and microfluidic devices. However, the controllability of liquid motion and the simplification of manufacturing process remain challenges. Inspired by the peristome of Nepenthes alata, a surface-tension-confined (STC) channel with biomimetic microcavities was fabricated facilely through UV exposure photolithography and partial plasma treatment. Perfect asymmetric liquid spreading was achieved by combination of microcavities and hydrophobic boundary, and the stability of pinning effect was demonstrated. The influences of structural features of microcavities on both liquid spreading and liquid pinning were investigated and the underlying mechanism was revealed. We also demonstrated the spontaneous unidirectional transport of liquid in 3D space and on tilting slope. In addition, through changing pits arrangement and wettability pattern, complex liquid motion paths and microreactors were realized. This work will open a new way for liquid manipulation and lab-on-chip applications.
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Affiliation(s)
- Yi Zhang
- School of Mechanical Engineering and Automation, Beihang University, Beijing 100191, China; (Y.Z.); (Y.G.); (L.Z.); (D.Z.)
| | - Yang Gan
- School of Mechanical Engineering and Automation, Beihang University, Beijing 100191, China; (Y.Z.); (Y.G.); (L.Z.); (D.Z.)
| | - Liwen Zhang
- School of Mechanical Engineering and Automation, Beihang University, Beijing 100191, China; (Y.Z.); (Y.G.); (L.Z.); (D.Z.)
| | - Deyuan Zhang
- School of Mechanical Engineering and Automation, Beihang University, Beijing 100191, China; (Y.Z.); (Y.G.); (L.Z.); (D.Z.)
- Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Huawei Chen
- School of Mechanical Engineering and Automation, Beihang University, Beijing 100191, China; (Y.Z.); (Y.G.); (L.Z.); (D.Z.)
- Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
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41
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Shi X, Zhang Y, Wu D, Wu T, Jiang S, Jiao Y, Wu S, Zhang Y, Hu Y, Ding W, Chu J. Femtosecond Laser-Assisted Top-Restricted Self-Growth Re-Entrant Structures on Shape Memory Polymer for Dynamic Pressure Resistance. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:12346-12356. [PMID: 32967422 DOI: 10.1021/acs.langmuir.0c02335] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Bioinspired surface material with re-entrant texture has been proven effective in exhibiting good pressure resistance to droplets with low surface tension under static conditions. In this work, we combined femtosecond laser cutting with shape memory polymer (SMP) and tape to fabricate re-entrant micropillar arrays by proposing a top-restricted self-growth (TRSG) strategy. Our proposed TRSG strategy simplifies the fabrication process and improves the processing efficiency of the re-entrant structure-based surface material. The structural parameters of the re-entrant micropillar array (microdisk diameter D, center-to-center distance P, and height H) can be adjusted through our TRSG processing method. To better characterize the anti-infiltration ability of various re-entrant micropillars, we studied the dynamic process of ethylene glycol droplet deformation by applying external vertical vibration to the surface material. Three parameters (vibration mode, amplitude, and frequency) of the external excitation and structural parameters of the re-entrant micropillar array were systemically investigated. We found that the surface material had better dynamic pressure resistance when P and D of the re-entrant texture were 650 and 500 μm, respectively, after heating for 6 min. This work provides new insights into the preparation and characterization of the surface material, which may find potential applications in microdroplet manipulation, drug testing, and biological sensors.
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Affiliation(s)
- Xiangchao Shi
- Department of Electronic Science and Technology, University of Science and Technology of China, Hefei 230026, China
| | - Yachao Zhang
- CAS Key Laboratory of Mechanical Behaviour and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China
| | - Dong Wu
- CAS Key Laboratory of Mechanical Behaviour and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China
| | - Tao Wu
- Department of Modern Mechanics, University of Science and Technology of China, Hefei 230026, China
| | - Shaojun Jiang
- CAS Key Laboratory of Mechanical Behaviour and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China
| | - Yunlong Jiao
- Institute of Tribology, Hefei University of Technology, Hefei 230009, China
| | - Sizhu Wu
- School of Instrument Science and Optoelectronics Engineering, Hefei University of Technology, Hefei 230009, China
| | - Yiyuan Zhang
- CAS Key Laboratory of Mechanical Behaviour and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China
| | - Yanlei Hu
- CAS Key Laboratory of Mechanical Behaviour and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China
| | - Weiping Ding
- Department of Electronic Science and Technology, University of Science and Technology of China, Hefei 230026, China
| | - Jiaru Chu
- CAS Key Laboratory of Mechanical Behaviour and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China
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42
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Self-propelled droplet transport on shaped-liquid surfaces. Sci Rep 2020; 10:14987. [PMID: 32917910 PMCID: PMC7486897 DOI: 10.1038/s41598-020-70988-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 06/24/2020] [Indexed: 11/29/2022] Open
Abstract
The transport of small amounts of liquids on solid surfaces is fundamental for microfluidics applications. Technologies allowing control of droplets of liquid on flat surfaces generally involve the generation of a wettability contrast. This approach is however limited by the resistance to motion caused by the direct contact between the droplet and the solid. We show here that this resistance can be drastically reduced by preventing direct contact with the help of dual-length scale micro-structures and the concept of “liquid-surfaces”. These new surfaces allow the gentle transport of droplets along defined paths and with fine control of their speed. Moreover, their high adhesion permits the capture of impacting droplets, opening new possibilities in applications such as fog harvesting and heat transfer.
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Li Y, Li J, Liu L, Yan Y, Zhang Q, Zhang N, He L, Liu Y, Zhang X, Tian D, Leng J, Jiang L. Switchable Wettability and Adhesion of Micro/Nanostructured Elastomer Surface via Electric Field for Dynamic Liquid Droplet Manipulation. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:2000772. [PMID: 32999834 PMCID: PMC7509640 DOI: 10.1002/advs.202000772] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 06/11/2020] [Indexed: 05/13/2023]
Abstract
Dynamic control of liquid wetting behavior on smart surfaces has attracted considerable concern owing to their important applications in directional motion, confined wetting and selective separation. Despite much progress in this regard, there still remains challenges in dynamic liquid droplet manipulation with fast response, no loss and anti-contamination. Herein, a strategy to achieve dynamic droplet manipulation and transportation on the electric field adaptive superhydrophobic elastomer surface is demonstrated. The superhydrophobic elastomer surface is fabricated by combining the micro/nanostructured clusters of hydrophobic TiO2 nanoparticles with the elastomer film, on which the micro/nanostructure can be dynamically and reversibly tuned by electric field due to the electric field adaptive deformation of elastomer film. Accordingly, fast and reversible transition of wetting state between Cassie state and Wenzel state and tunable adhesion on the surface via electric field induced morphology transformation can be obtained. Moreover, the motion states of the surface droplets can be controlled dynamically and precisely, such as jumping and pinning, catching and releasing, and controllable liquid transfer without loss and contamination. Thus this work would open the avenue for dynamic liquid manipulation and transportation, and gear up the broad application prospects in liquid transfer, selective separation, anti-fog, anti-ice, microfluidics devices, etc.
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Affiliation(s)
- Yan Li
- Key Laboratory of Bio‐Inspired Smart Interfacial Science and Technology of Ministry of EducationSchool of ChemistryBeihang UniversityBeijing100191P. R. China
| | - Jinrong Li
- National Key Laboratory of Science and Technology on Advanced Composites in Special EnvironmentsHarbin Institute of TechnologyHarbinHeilongjiang150080P. R. China
| | - Liwu Liu
- Department of Astronautical Science and MechanicsHarbin Institute of TechnologyHarbinHeilongjiang150001P. R. China
| | - Yufeng Yan
- Key Laboratory of Bio‐Inspired Smart Interfacial Science and Technology of Ministry of EducationSchool of ChemistryBeihang UniversityBeijing100191P. R. China
| | - Qiuya Zhang
- Key Laboratory of Bio‐Inspired Smart Interfacial Science and Technology of Ministry of EducationSchool of ChemistryBeihang UniversityBeijing100191P. R. China
| | - Na Zhang
- Key Laboratory of Bio‐Inspired Smart Interfacial Science and Technology of Ministry of EducationSchool of ChemistryBeihang UniversityBeijing100191P. R. China
| | - Linlin He
- Key Laboratory of Bio‐Inspired Smart Interfacial Science and Technology of Ministry of EducationSchool of ChemistryBeihang UniversityBeijing100191P. R. China
| | - Yanju Liu
- Department of Astronautical Science and MechanicsHarbin Institute of TechnologyHarbinHeilongjiang150001P. R. China
| | - Xiaofang Zhang
- School of Mathematics and PhysicsUniversity of Science and Technology BeijingBeijing100083P. R. China
| | - Dongliang Tian
- Key Laboratory of Bio‐Inspired Smart Interfacial Science and Technology of Ministry of EducationSchool of ChemistryBeihang UniversityBeijing100191P. R. China
- Beijing Advanced Innovation Center for Biomedical EngineeringBeihang UniversityBeijing100191P. R. China
| | - Jinsong Leng
- National Key Laboratory of Science and Technology on Advanced Composites in Special EnvironmentsHarbin Institute of TechnologyHarbinHeilongjiang150080P. R. China
| | - Lei Jiang
- Key Laboratory of Bio‐Inspired Smart Interfacial Science and Technology of Ministry of EducationSchool of ChemistryBeihang UniversityBeijing100191P. R. China
- Beijing Advanced Innovation Center for Biomedical EngineeringBeihang UniversityBeijing100191P. R. China
- Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing100191P. R. China
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Tang B, Meng C, Zhuang L, Groenewold J, Qian Y, Sun Z, Liu X, Gao J, Zhou G. Field-Induced Wettability Gradients for No-Loss Transport of Oil Droplets on Slippery Surfaces. ACS APPLIED MATERIALS & INTERFACES 2020; 12:38723-38729. [PMID: 32846489 DOI: 10.1021/acsami.0c06389] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Transporting oil droplets is crucial for a wide range of industrial and biomedical applications but remains highly challenging due to the large contact angle hysteresis on most solid surfaces. A liquid-infused slippery surface has a low hysteresis contact angle and is a highly promising platform if sufficient wettability gradient can be created. Current strategies used to create wettability gradient typically rely on the engineering of the chemical composition or geometrical structure. However, these strategies are inefficient on a slippery surface because the infused liquid tends to conceal the gradient in the chemical composition and small-scale geometrical structure. Magnifying the structure, on the other hand, will significantly distort the surface topography, which is unwanted in practice. In this study, we address this challenge by introducing a field-induced wettability gradient on a flat slippery surface. By printing radial electrodes array, we can pattern the electric field, which induces gradient contact angles. Theoretical analysis and experimental results reveal that the droplet transport behavior can be captured by a nondimensional electric Bond number. Our surface enables no-loss transport of various types of droplets, which we expect to find important applications such as heat transfer, anticontamination, microfluidics, and biochemical analysis.
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Affiliation(s)
- Biao Tang
- National Center for International Research on Green Optoelectronics, Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, P. R. China
| | - Chuanzhi Meng
- National Center for International Research on Green Optoelectronics, Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, P. R. China
| | - Lei Zhuang
- National Center for International Research on Green Optoelectronics, Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, P. R. China
| | - Jan Groenewold
- National Center for International Research on Green Optoelectronics, Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, P. R. China
- Van't Hoff Laboratory for Physical and Colloid Chemistry, Debye Research Institute, Utrecht University, Padualaan 8, Utrecht 3584 CH, The Netherlands
| | - Yuyang Qian
- National Center for International Research on Green Optoelectronics, Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, P. R. China
| | - Zhongqian Sun
- National Center for International Research on Green Optoelectronics, Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, P. R. China
| | - Xueli Liu
- Faculty of Science and Technology, University of Twente, Enschede 7500 AE, The Netherlands
| | - Jun Gao
- Faculty of Science and Technology, University of Twente, Enschede 7500 AE, The Netherlands
| | - Guofu Zhou
- National Center for International Research on Green Optoelectronics, Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, P. R. China
- Shenzhen Guohua Optoelectronics Tech. Co. Ltd., Academy of Shenzhen Guohua, Optoelectronics, Shenzhen 518110, P. R. China
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Wang L, Li J, Zhang B, Feng S, Zhang M, Wu D, Lu Y, Kai JJ, Liu J, Wang Z, Jiang L. Counterintuitive Ballistic and Directional Liquid Transport on a Flexible Droplet Rectifier. RESEARCH 2020; 2020:6472313. [PMID: 32885170 PMCID: PMC7453356 DOI: 10.34133/2020/6472313] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 07/20/2020] [Indexed: 11/06/2022]
Abstract
Achieving the directional and long-range droplet transport on solid surfaces is widely preferred for many practical applications but has proven to be challenging. Particularly, directionality and transport distance of droplets on hydrophobic surfaces are mutually exclusive. Here, we report that drain fly, a ubiquitous insect maintaining nonwetting property even in very high humidity, develops a unique ballistic droplet transport mechanism to meet these demanding challenges. The drain fly serves as a flexible rectifier to allow for a directional and long-range propagation as well as self-removal of a droplet, thus suppressing unwanted liquid flooding. Further investigation reveals that this phenomenon is owing to the synergistic conjunction of multiscale roughness, structural periodicity, and flexibility, which rectifies the random and localized droplet nucleation (nanoscale and microscale) into a directed and global migration (millimeter-scale). The mechanism we have identified opens up a new approach toward the design of artificial rectifiers for broad applications.
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Affiliation(s)
- Lei Wang
- Beijing Key Lab of Cryo-Biomedical Engineering and Key Lab of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Jing Li
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong 999077, China
| | - Bo Zhang
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Shile Feng
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong 999077, China
| | - Mei Zhang
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong 999077, China
| | - Dong Wu
- 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, Anhui 230027, China
| | - Yang Lu
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong 999077, China
| | - Ji Jung Kai
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong 999077, China
| | - Jing Liu
- Beijing Key Lab of Cryo-Biomedical Engineering and Key Lab of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Zuankai Wang
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong 999077, China
| | - Lei Jiang
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
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46
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Hu S, Cao X, Reddyhoff T, Puhan D, Vladescu SC, Wang J, Shi X, Peng Z, deMello AJ, Dini D. Liquid repellency enhancement through flexible microstructures. SCIENCE ADVANCES 2020; 6:eaba9721. [PMID: 32923610 PMCID: PMC7457340 DOI: 10.1126/sciadv.aba9721] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 06/18/2020] [Indexed: 05/29/2023]
Abstract
Artificial liquid-repellent surfaces have attracted substantial scientific and industrial attention with a focus on creating functional topological features; however, the role of the underlying structures has been overlooked. Recent developments in micro-nanofabrication allow us now to construct a skin-muscle type system combining interfacial liquid repellence atop a mechanically functional structure. Specifically, we design surfaces comprising bioinspired, mushroom-like repelling heads and spring-like flexible supports, which are realized by three-dimensional direct laser lithography. The flexible supports elevate liquid repellency by resisting droplet impalement and reducing contact time. This, previously unknown, use of spring-like flexible supports to enhance liquid repellency provides an excellent level of control over droplet manipulation. Moreover, this extends repellent microstructure research from statics to dynamics and is envisioned to yield functionalities and possibilities by linking functional surfaces and mechanical metamaterials.
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Affiliation(s)
- Songtao Hu
- State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiaobao Cao
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich 8093, Switzerland
| | - Tom Reddyhoff
- Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, UK
| | - Debashis Puhan
- Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, UK
| | | | - Jing Wang
- Institute of Environmental Engineering, ETH Zurich, Zurich 8093, Switzerland
- Laboratory for Advanced Analytical Technologies, Empa, Dübendorf 8600, Switzerland
| | - Xi Shi
- State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhike Peng
- State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Andrew J. deMello
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich 8093, Switzerland
| | - Daniele Dini
- Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, UK
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47
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Chu F, Luo J, Hao C, Zhang J, Wu X, Wen D. Directional Transportation of Impacting Droplets on Wettability-Controlled Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:5855-5862. [PMID: 32390439 DOI: 10.1021/acs.langmuir.0c00601] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Although a superhydrophobic surface could realize rapid rebounding (i.e., short contact time) of an orthogonal impacting droplet, the rebounding along the original impacting route may limit its engineering application; in contrast, the directional transportation seems to be more promising. Here, we achieve directional transportation of a droplet impacting a wettability-controlled surface. When the droplet eccentrically impacts on the boundary between the superhydrophobic part and the hydrophilic part, it undergoes spreading, retracting, departure, throwing, and breaking up stages, and finally bounces off directionally. The directional transportation distance could even reach more than ten times the droplet size, considered the adhesion length (i.e., covering length on the hydrophilic part by the droplet at the maximum spreading) is optimized. However, there is a critical adhesion length, above which the directional transportation does not occur. To be more generalized, the adhesion length is de-dimensionalized by the maximum spreading radius, and the results show that as the dimensionless adhesion length increases, the transportation distance first increases and then decreases to zero. Under the present impacting conditions, the optimal dimensionless adhesion length corresponding to the maximum transportation distance is near 0.4, and the critical dimensionless adhesion length is about 0.7. These results provide a fundamental understanding of droplet directional transportation and could be useful for related engineering applications.
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Affiliation(s)
- Fuqiang Chu
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
- School of Aeronautic Science and Engineering, Beihang University, Beijing 100191, China
| | - Jia Luo
- School of Aeronautic Science and Engineering, Beihang University, Beijing 100191, China
- Shenyuan Honors College, Beihang University, Beijing 100191, China
| | - Chonglei Hao
- School of Mechanical Engineering and Automation, Harbin Institute of Technology, Shenzhen 518055, China
| | - Jun Zhang
- School of Aeronautic Science and Engineering, Beihang University, Beijing 100191, China
| | - Xiaomin Wu
- Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China
| | - Dongsheng Wen
- School of Aeronautic Science and Engineering, Beihang University, Beijing 100191, China
- School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, U.K
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Zhang P, Chen C, Su X, Mai J, Gu Y, Tian Z, Zhu H, Zhong Z, Fu H, Yang S, Chakrabarty K, Huang TJ. Acoustic streaming vortices enable contactless, digital control of droplets. SCIENCE ADVANCES 2020; 6:eaba0606. [PMID: 32577516 PMCID: PMC7286667 DOI: 10.1126/sciadv.aba0606] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 03/31/2020] [Indexed: 05/22/2023]
Abstract
Advances in lab-on-a-chip technologies are driven by the pursuit of programmable microscale bioreactors or fluidic processors that mimic electronic functionality, scalability, and convenience. However, few fluidic mechanisms allow for basic logic operations on rewritable fluidic paths due to cross-contamination, which leads to random interference between "fluidic bits" or droplets. Here, we introduce a mechanism that allows for contact-free gating of individual droplets based on the scalable features of acoustic streaming vortices (ASVs). By shifting the hydrodynamic equilibrium positions inside interconnected ASVs with multitonal electrical signals, different functions such as controlling the routing and gating of droplets on rewritable fluidic paths are demonstrated with minimal biochemical cross-contamination. Electrical control of this ASV-based mechanism allows for unidirectional routing and active gating behaviors, which can potentially be scaled to functional fluidic processors that can regulate the flow of droplets in a manner similar to the current in transistor arrays.
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Affiliation(s)
- Peiran Zhang
- Department of Mechanical Engineering and Materials Science, Duke University, NC 27708, USA
| | - Chuyi Chen
- Department of Mechanical Engineering and Materials Science, Duke University, NC 27708, USA
| | - Xingyu Su
- Department of Mechanical Engineering and Materials Science, Duke University, NC 27708, USA
| | - John Mai
- Alfred E. Mann Institute for Biomedical Engineering, University of Southern California, Los Angeles, CA 90007, USA
| | - Yuyang Gu
- Department of Mechanical Engineering and Materials Science, Duke University, NC 27708, USA
| | - Zhenhua Tian
- Department of Mechanical Engineering and Materials Science, Duke University, NC 27708, USA
| | - Haodong Zhu
- Department of Mechanical Engineering and Materials Science, Duke University, NC 27708, USA
| | - Zhanwei Zhong
- Department of Electrical and Computer Engineering, Duke University, NC 27708, USA
| | - Hai Fu
- Department of Mechanical Engineering and Materials Science, Duke University, NC 27708, USA
| | - Shujie Yang
- Department of Mechanical Engineering and Materials Science, Duke University, NC 27708, USA
| | | | - Tony Jun Huang
- Department of Mechanical Engineering and Materials Science, Duke University, NC 27708, USA
- Corresponding author.
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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: 1.4] [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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50
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Wang Z, Song S, Yang J, Liu X, Sherazi TA, Li S, Zhang S. Controllable Janus porous membrane with liquids manipulation for diverse intelligent energy-free applications. J Memb Sci 2020. [DOI: 10.1016/j.memsci.2020.117954] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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