51
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Liu J, Feng Z, Ouyang W, Shui L, Liu Z. Spontaneous Movement of a Droplet on a Conical Substrate: Theoretical Analysis of the Driving Force. ACS OMEGA 2022; 7:20975-20982. [PMID: 35755370 PMCID: PMC9219097 DOI: 10.1021/acsomega.2c01713] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 05/27/2022] [Indexed: 06/15/2023]
Abstract
Experiments and simulations have shown that a droplet can move spontaneously and directionally on a conical substrate. The driving force originating from the gradient of curvatures is revealed as the self-propulsion mechanism. Theoretical analysis of the driving force is highly desirable; currently, most of them are based on a perturbative theory with assuming a weakly curved substrate. However, this assumption is valid only when the size of the droplet is far smaller than the curvature radius of the substrate. In this paper, we derive a more accurate analytical model for describing the driving force by exploring the geometric characteristics of a spherical droplet on a cylindrical substrate. In contrast to the perturbative solution, our model is valid under a much weaker condition, i.e., the contact region between the droplet and the substrate is small compared with the curvature radius of the substrate. Therefore, we show that for superhydrophobic surfaces, the derived analytical model is applicable even if the droplet is very close to the apex of a conical substrate. Our approach opens an avenue for studying the behavior of droplets on the tip of the conical substrate theoretically and could also provide guidance for the experimental design of curved surfaces to control the directional motion of droplets.
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52
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Yang C, Zeng Q, Huang J, Guo Z. Droplet manipulation on superhydrophobic surfaces based on external stimulation: A review. Adv Colloid Interface Sci 2022; 306:102724. [DOI: 10.1016/j.cis.2022.102724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 06/14/2022] [Accepted: 06/22/2022] [Indexed: 11/01/2022]
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53
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AlPO
4
film with rose surface structure: One‐step coating process, superhydrophilic and rapid super‐spreading. NANO SELECT 2022. [DOI: 10.1002/nano.202100308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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54
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Li C, Liu M, Yao Y, Zhang B, Peng Z, Chen S. Locust-Inspired Direction-Dependent Transport Based on a Magnetic-Responsive Asymmetric-Microplate-Arrayed Surface. ACS APPLIED MATERIALS & INTERFACES 2022; 14:23817-23825. [PMID: 35548931 DOI: 10.1021/acsami.2c01882] [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
Inspired by the highly efficient jumping mechanism of locusts, a magnetic-responsive asymmetric-microplate-arrayed surface is designed. Elastic energy can be stored in the microplate and rapidly released by loading and removing a magnetic field. Similar to the bouncing behavior of the locust, objects deposited on the surface of the microplate-arrayed surface will bounce suddenly. It is found that the continuous transport behavior can be induced in the moving magnetic field and the direction-dependent transport is well achieved by preparing the secondary microstructure. The results show that both the weight and transport velocity of the transported object in the forward transport direction are much greater than those in the reverse transport direction. Furthermore, the anisotropic transport property can be strengthened with the increase of the height of the secondary structure. Such surfaces can transport objects with either soft or hard stiffness, as well as objects with different geometric configurations, and the transport path can be arbitrarily programmed. Based on the transport mechanism, a flexible microconvey belt is further designed, which can transport objects in any controlled direction. Such a simple technique can provide new design ideas for directional microtransport requirements.
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Affiliation(s)
- Chenghao Li
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures, Beijing Institute of Technology, Beijing 100081, China
| | - Ming Liu
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures, Beijing Institute of Technology, Beijing 100081, China
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yin Yao
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures, Beijing Institute of Technology, Beijing 100081, China
| | - Bo Zhang
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures, Beijing Institute of Technology, Beijing 100081, China
| | - Zhilong Peng
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures, Beijing Institute of Technology, Beijing 100081, China
| | - Shaohua Chen
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures, Beijing Institute of Technology, Beijing 100081, China
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55
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Tian N, Chen K, Wei J, Zhang J. Robust Superamphiphobic Fabrics with Excellent Hot Liquid Repellency and Hot Water Vapor Resistance. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:5891-5899. [PMID: 35482598 DOI: 10.1021/acs.langmuir.2c00532] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Superamphiphobic surfaces progress rapidly but suffer from the issues of low repellency to hot liquids, complicated and nonaqueous preparation methods, and low durability. Here, a simple waterborne approach is developed to fabricate robust superamphiphobic fabrics with excellent hot liquid repellency and hot water vapor resistance. First, a perfluorodecyl polysiloxane (FD-POS) aqueous suspension was prepared by hydrolytic cocondensation of (3-glycidyloxy propyl)trimethoxysilane and 1H,1H,2H,2H-perfluorodecyltriethoxysilane with SiO2 particles. Then, the superamphiphobic fabrics were fabricated by dipping polyester fabrics in the suspension, which were then cured. The fabrics show excellent superamphiphobicity owing to the combination of the hierarchical micro-/nanostructure and FD-POS with very low surface energy. The superamphiphobic fabrics feature excellent hot liquid repellency even for a large volume of 130.0 °C soybean oil and condensed small droplets from ∼90.0 °C water vapor. This is attributed to its high superamphiphobicity, excellent hot water vapor resistance, and outstanding thermal durability. In addition, the superamphiphobic fabrics exhibit high mechanical and chemical durability against washing, abrasion, and immersion in corrosive or organic liquids. Thus, hot liquid repellent superamphiphobic fabrics may find applications in various fields such as antiadhesion of various hot liquids and in efficiently preventing scalding.
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Affiliation(s)
- Ning Tian
- Center of Eco-material and Green Chemistry, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Kai Chen
- Center of Eco-material and Green Chemistry, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Jinfei Wei
- Center of Eco-material and Green Chemistry, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
| | - Junping Zhang
- Center of Eco-material and Green Chemistry, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
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56
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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: 3.5] [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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57
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Tang Z, Luan K, Xu B, Liu H. Unidirectional transport of both wettable and nonwettable liquids on an asymmetrically concave structured surface. FUNDAMENTAL RESEARCH 2022. [DOI: 10.1016/j.fmre.2022.03.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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58
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Liu M, Li C, Peng Z, Chen S, Zhang B. Simple but Efficient Method To Transport Droplets on Arbitrarily Controllable Paths. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:3917-3924. [PMID: 35297634 DOI: 10.1021/acs.langmuir.2c00194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The flexible manipulation of droplets manifests a wide spectrum of applications, such as micro-flow control, drug-targeted therapy, and microelectromechanical system heat dissipation. How to realize the efficient control of droplets has become a problem of concern. In this paper, a simple method that can realize the transport of droplets along any controllable path is proposed. It not only has a simple preparation process and clear transport mechanism but is also easy to realize in manipulation technology. A magnetic-sensitive surface is prepared by filling a polymer matrix with magnetic particles and immersing in a lubricant. Under the action of an external magnetic field, rough microstructures are generated locally on the surface, forming the wettability gradient with the area far away from the field. Moving the magnetic field, the wettability gradient region moves accordingly and drives droplets to transport. To better control the transport path of droplets or realize a more complex path design, a ring-shaped magnetic field is further adopted, during which the droplet is automatically located in the ring-shaped region and moves with the movement of the ring-shaped magnetic field. The present technique is simple and easy to implement, which should be helpful in the field of precise regulation of the droplet position.
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Affiliation(s)
- Ming Liu
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Chenghao Li
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Zhilong Peng
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Shaohua Chen
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Bo Zhang
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures, Beijing Institute of Technology, Beijing 100081, People's Republic of China
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59
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Wei J, Liang Y, Chen X, Gorb SN, Wu Z, Li H, Wu J. Enhanced Flexibility of the Segmented Honey Bee Tongue with Hydrophobic Tongue Hairs. ACS APPLIED MATERIALS & INTERFACES 2022; 14:12911-12919. [PMID: 35257584 DOI: 10.1021/acsami.2c00431] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Fibrous surfaces in nature have already exhibited excellent functions that are normally ascribed to the synergistic effects of special structures and material properties. The honey bee tongue, foraging liquid food in nature, has a unique segmented surface covered with dense hairs. Since honey bees are capable of using their tongue to adapt to possibly the broadest range of feeding environments to exploit every possible source of liquids, the surface properties of the tongue, especially the covering hairs, would likely represent an evolutionary optimization. In this paper, we show that their tongue hairs are stiff and hydrophobic, the latter of which is highly unexpected as the structure is designed for liquid capturing. We found that such hydrophobicity can prevent those stiff hairs from being adhered to the soft tongue surface, which could significantly enhance the deformability of the tongue when honey bees feed at various surfaces and promote their adaptability to different environments. These findings bridge the relationship between surface wettability and structural characteristics, which may shed new light on designing flexible microstructured fiber systems to transport viscous liquids.
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Affiliation(s)
- Jiangkun Wei
- School of Aeronautics and Astronautics, Sun Yat-Sen University, Guangzhou 510006, P. R. China
| | - Yingqi Liang
- School of Aeronautics and Astronautics, Sun Yat-Sen University, Guangzhou 510006, P. R. China
| | - Xingdi Chen
- School of Aeronautics and Astronautics, Sun Yat-Sen University, Guangzhou 510006, P. R. China
| | - Stanislav N Gorb
- Functional Morphology and Biomechanics, Zoology Department, Kiel University, Am Botanischen Garten 9, 24118 Kiel, Germany
| | - Zhigang Wu
- School of Aeronautics and Astronautics, Sun Yat-Sen University, Guangzhou 510006, P. R. China
| | - Huizeng Li
- Key Laboratory of Green Printing, Institute of Chemistry, Chinese Academy of Sciences (ICCAS), Beijing 100190, P. R. China
| | - Jianing Wu
- School of Aeronautics and Astronautics, Sun Yat-Sen University, Guangzhou 510006, P. R. China
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60
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Qian C, Zhou F, Wang T, Li Q, Hu D, Chen X, Wang Z. Pancake Jumping of Sessile Droplets. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2103834. [PMID: 35032105 PMCID: PMC8895051 DOI: 10.1002/advs.202103834] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 12/06/2021] [Indexed: 05/26/2023]
Abstract
Rapid droplet shedding from surfaces is fundamentally interesting and important in numerous applications such as anti-icing, anti-fouling, dropwise condensation, and electricity generation. Recent efforts have demonstrated the complete rebound or pancake bouncing of impinging droplets by tuning the physicochemical properties of surfaces and applying external control, however, enabling sessile droplets to jump off surfaces in a bottom-to-up manner is challenging. Here, the rapid jumping of sessile droplets, even cold droplets, in a pancake shape is reported by engineering superhydrophobic magnetically responsive blades arrays. This largely unexplored droplet behavior, termed as pancake jumping, exhibits many advantages such as short interaction time and high energy conversion efficiency. The critical conditions for the occurrence of this new phenomenon are also identified. This work provides a new toolkit for the attainment of well-controlled and active steering of both sessile and impacting droplets for a wide range of applications.
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Affiliation(s)
- Chenlu Qian
- MIIT Key Laboratory of Thermal Control of Electronic EquipmentSchool of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing210094China
| | - Fan Zhou
- MIIT Key Laboratory of Thermal Control of Electronic EquipmentSchool of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing210094China
| | - Ting Wang
- Department of Mechanical EngineeringCity University of Hong KongHong Kong999077China
| | - Qiang Li
- MIIT Key Laboratory of Thermal Control of Electronic EquipmentSchool of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing210094China
| | - Dinghua Hu
- MIIT Key Laboratory of Thermal Control of Electronic EquipmentSchool of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing210094China
| | - Xuemei Chen
- MIIT Key Laboratory of Thermal Control of Electronic EquipmentSchool of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing210094China
| | - Zuankai Wang
- Department of Mechanical EngineeringCity University of Hong KongHong Kong999077China
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61
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Lu H, Shi W, Guo Y, Guan W, Lei C, Yu G. Materials Engineering for Atmospheric Water Harvesting: Progress and Perspectives. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2110079. [PMID: 35122451 DOI: 10.1002/adma.202110079] [Citation(s) in RCA: 51] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/06/2022] [Indexed: 06/14/2023]
Abstract
Atmospheric water harvesting (AWH) is emerging as a promising strategy to produce fresh water from abundant airborne moisture to overcome the global clean water shortage. The ubiquitous moisture resources allow AWH to be free from geographical restrictions and potentially realize decentralized applications, making it a vital parallel or supplementary freshwater production approach to liquid water resource-based technologies. Recent advances in regulating chemical properties and micro/nanostructures of moisture-harvesting materials have demonstrated new possibilities to promote enhanced device performance and new understandings. This perspective aims to provide a timely overview on the state-of-the-art materials design and how they serve as the active components in AWH. First, the key processes of AWH, including vapor condensation, droplet nucleation, growth, and departure are outlined, and the desired material properties based on the fundamental mechanisms are discussed. Then, how tailoring materials-water interactions at the molecular level play a vital role in realizing high water uptake and low energy consumption is shown. Last, the challenges and outlook on further improving AWH from material designs and system engineering aspects are highlighted.
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Affiliation(s)
- Hengyi Lu
- Materials Science and Engineering Program and Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Wen Shi
- Materials Science and Engineering Program and Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Youhong Guo
- Materials Science and Engineering Program and Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Weixin Guan
- Materials Science and Engineering Program and Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Chuxin Lei
- Materials Science and Engineering Program and Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Guihua Yu
- Materials Science and Engineering Program and Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
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62
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Zhao L, Seshadri S, Liang X, Bailey SJ, Haggmark M, Gordon M, Helgeson ME, Read de Alaniz J, Luzzatto-Fegiz P, Zhu Y. Depinning of Multiphase Fluid Using Light and Photo-Responsive Surfactants. ACS CENTRAL SCIENCE 2022; 8:235-245. [PMID: 35233455 PMCID: PMC8875439 DOI: 10.1021/acscentsci.1c01127] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Indexed: 05/03/2023]
Abstract
The development of noninvasive and robust strategies for manipulation of droplets and bubbles is crucial in applications such as boiling and condensation, electrocatalysis, and microfluidics. In this work, we realize the swift departure of droplets and bubbles from solid substrates by introducing photoresponsive surfactants and applying asymmetric illumination, thereby inducing a "photo-Marangoni" lift force. Experiments show that a pinned toluene droplet can depart the substrate in only 0.38 s upon illumination, and the volume of an air bubble at departure is reduced by 20%, indicating significantly faster departure. These benefits can be achieved with moderate light intensities and dilute surfactant concentrations, without specially fabricated substrates, which greatly facilitates practical applications. Simulations suggest that the net departure force includes contributions from viscous stresses directly caused by the Marangoni flow, as well as from pressure buildup due to flow stagnation at the contact line. The manipulation scheme proposed here shows potential for applications requiring droplet and bubble removal from working surfaces.
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Affiliation(s)
- Lei Zhao
- Department
of Mechanical Engineering, University of
California, Santa Barbara, Santa
Barbara, California 93106-5070, United States
| | - Serena Seshadri
- Department
of Chemistry, University of California at
Santa Barbara, Santa Barbara, California 93106-5070, United States
| | - Xichen Liang
- Department
of Chemical Engineering, University of California
at Santa Barbara, Santa Barbara, California 93106-5070, United States
| | - Sophia J. Bailey
- Department
of Chemistry, University of California at
Santa Barbara, Santa Barbara, California 93106-5070, United States
| | - Michael Haggmark
- Department
of Chemical Engineering, University of California
at Santa Barbara, Santa Barbara, California 93106-5070, United States
| | - Michael Gordon
- Department
of Chemical Engineering, University of California
at Santa Barbara, Santa Barbara, California 93106-5070, United States
| | - Matthew E. Helgeson
- Department
of Chemical Engineering, University of California
at Santa Barbara, Santa Barbara, California 93106-5070, United States
| | - Javier Read de Alaniz
- Department
of Chemistry, University of California at
Santa Barbara, Santa Barbara, California 93106-5070, United States
| | - Paolo Luzzatto-Fegiz
- Department
of Mechanical Engineering, University of
California, Santa Barbara, Santa
Barbara, California 93106-5070, United States
| | - Yangying Zhu
- Department
of Mechanical Engineering, University of
California, Santa Barbara, Santa
Barbara, California 93106-5070, United States
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63
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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: 8] [Impact Index Per Article: 4.0] [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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64
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Tang Y, Yang X, Li Y, Lu Y, Zhu D. Robust Micro-Nanostructured Superhydrophobic Surfaces for Long-Term Dropwise Condensation. NANO LETTERS 2021; 21:9824-9833. [PMID: 34472863 DOI: 10.1021/acs.nanolett.1c01584] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Design of hierarchical micromorphology represents an important strategy for developing functional surfaces but has yet to be achieved for promising long-term dropwise condensation. Herein, micropapillaes overlaid with nanograss were created to enhance dropwise condensation. By analyzing the nucleation and evolution of the condensate droplets, we elucidated that these hierarchical micro-nanostructures topologized tapered gaps, which produced upward pressure, to achieve spontaneous dislodging of condensate microdroplet out of gaps, and then to trigger microdroplet navigation before finally departing from the surface by coalescence-induced jumping. The high mobility of condensate delayed flooding and contributed to a very high heat transfer coefficient of 218 kW·m-2·K-1. Moreover, these micropapillaes served as forts that protected the nanograss from being destroyed, resulting in improved mechanical and chemical robustness. Our work proposed new examples of topology creation for long-term dropwise condensation heat transfer and shed light on application integration of such promising functional surfaces.
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Affiliation(s)
- Yu Tang
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Xiaolong Yang
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Yimin Li
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Yao Lu
- Department of Chemistry, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Di Zhu
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
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65
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Song YY, Yu ZP, Dong LM, Zhu ML, Ye ZC, Shi YJ, Liu Y. Cactus-Inspired Janus Membrane with a Conical Array of Wettability Gradient for Efficient Fog Collection. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:13703-13711. [PMID: 34767375 DOI: 10.1021/acs.langmuir.1c02368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Fog collection plays an important role in alleviating the global water shortage. Despite great progress in creating bionic surfaces to collect fog, water droplets still could adhere to the microscale hydrophilic region and reach the thermodynamic stable state before falling, which delays the transport of water and hinders the continuous fog collection. Inspired by lotus leaves and cactuses, we designed a Janus membrane that functions to both collect fog from the air and transport it to a certain region. The Janus membrane with opposite wettability contains conical microcolumns with a wettability gradient and hydrophilic copper mesh surface. The apexes of conical microcolumns are superhydrophobic and the rest are hydrophobic. The fog droplets were deposited, coalesced, and directionally transported to the bottom of the conical microcolumns. Then, the droplets unidirectionally passed through the membrane and flowed into the water film on the surface of the copper mesh. The asymmetric structural and wettability merits endow the Janus membrane with an improved fog collection of ∼7.05 g/cm2/h. The study is valuable for designing and developing fluid control equipment in fog collection, liquid manipulation, and microfluidics.
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Affiliation(s)
- Yun-Yun Song
- School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu, P. R. China
| | - Zhao-Peng Yu
- School of Automotive Engineering, Changshu Institute of Technology, No. 99 Hushan Road, Changshu, Suzhou 215500, P. R. China
| | - Li-Ming Dong
- School of Automotive Engineering, Changshu Institute of Technology, No. 99 Hushan Road, Changshu, Suzhou 215500, P. R. China
| | - Mao-Lin Zhu
- School of Automotive Engineering, Changshu Institute of Technology, No. 99 Hushan Road, Changshu, Suzhou 215500, P. R. China
| | - Zhi-Chun Ye
- School of Automotive Engineering, Changshu Institute of Technology, No. 99 Hushan Road, Changshu, Suzhou 215500, P. R. China
| | - Yuan-Ji Shi
- Department of Mechanical Engineering, Nanjing Institute of Industry Technology, Nanjing 210046, Jiangsu, P. R. China
| | - Yan Liu
- Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022, P. R. China
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66
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Zhuang K, Lu Y, Wang X, Yang X. Architecture-Driven Fast Droplet Transport without Mass Loss. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:12519-12528. [PMID: 34606720 DOI: 10.1021/acs.langmuir.1c01608] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Spontaneous droplet transport without mass loss has great potential applications in the fields of energy and biotechnology, but it remains challenging due to the difficulty in obtaining a sufficient driving force for the transport while suppressing droplet mass loss. Learning from the slippery peristome of Nepenthes alata and wedge topology of a shorebird beak that can spontaneously feed water against gravity, a combined system consisting of two face-to-face hydrophilic slippery liquid-infused porous surfaces (SLIPS) with variable beak-like opening and spacing was proposed to constrain the droplet in-between and initiate fast droplet transport over a long distance of 75 mm with a maximum speed of 12.2 mm·s-1 without mass loss by taking advantage of the Laplace pressure gradient induced by the asymmetric shape of the constrained droplet. The theoretical model based on the Navier-Stokes equation was developed to interpret the corresponding mechanism of the droplet transport process. In addition, in situ sophisticated droplet manipulations such as droplet mixing are readily feasible when applying flexible 304 stainless foil as the substrate of SLIPS. It is believed that extended research would contribute to new references for the precise and fast droplet motion control intended for energy harvest and water collection devices.
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Affiliation(s)
- Kai Zhuang
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Yao Lu
- Department of Chemistry, Queen Mary University of London, London E1 4NS, U.K
| | - Xiaolei Wang
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Xiaolong Yang
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
- Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, PR China
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67
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Han X, Tang X, Zhao H, Li W, Li J, Wang L. Spatio-temporal maneuvering of impacting drops. MATERIALS HORIZONS 2021; 8:3133-3140. [PMID: 34570140 DOI: 10.1039/d1mh00836f] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Controlling impacting drops on nonwetting surfaces is desired in multifarious processes. Efforts have been made to solely spatially control the drop movement after the impact or solely temporally reduce liquid-solid contact via surface design. We present a fin-stripe nonwetting surface that enables spatial offset maximization and temporal contact minimization simultaneously, just via structure design without the need for external energies. The wetting stripe provides a large wettability gradient for lateral movement, while the macroscale nonwetting fin restricts the drop movement direction and confines drop spreading for contact time reduction. The fin-stripe surface can decrease the contact time by roughly 30% and provide a normalized lateral distance of roughly 20, an order of magnitude larger than the reported values. Our surface enables effective spatio-temporal maneuvering of impacting drops, essential for various applications that involve liquid transport.
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Affiliation(s)
- Xing Han
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong.
- Zhejiang Institute of Research and Innovation, The University of Hong Kong, 311300 Hangzhou, Zhejiang, China
| | - Xin Tang
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong.
- Zhejiang Institute of Research and Innovation, The University of Hong Kong, 311300 Hangzhou, Zhejiang, China
| | - Haibo Zhao
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong.
- Zhejiang Institute of Research and Innovation, The University of Hong Kong, 311300 Hangzhou, Zhejiang, China
- Department of Mechanics and Aerospace Engineering, Southern University of Science and Technology, 518055 Shenzhen, Guangdong, China
| | - Wei Li
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong.
- Zhejiang Institute of Research and Innovation, The University of Hong Kong, 311300 Hangzhou, Zhejiang, China
| | - Jiaqian Li
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong.
- Zhejiang Institute of Research and Innovation, The University of Hong Kong, 311300 Hangzhou, Zhejiang, China
| | - Liqiu Wang
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong.
- Zhejiang Institute of Research and Innovation, The University of Hong Kong, 311300 Hangzhou, Zhejiang, China
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68
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Dong J, Fan FR, Tian ZQ. Droplet-based nanogenerators for energy harvesting and self-powered sensing. NANOSCALE 2021; 13:17290-17309. [PMID: 34647553 DOI: 10.1039/d1nr05386h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The energy crisis is a continuing topic for all human beings, threatening the development of human society. Accordingly, harvesting energy from the surrounding environment, such as wind, water flow and solar power, has become a promising direction for the research community. Water contains tremendous energy in a variety of forms, such as rivers, ocean waves, tides, and raindrops. Among them, raindrop energy is the most abundant. Raindrop energy not only can complement other forms of energy, such as solar energy, but also have potential applications in wearable and universal energy collectors. Over the past few years, droplet-based electricity nanogenerators (DENG) have attracted significant attention due to their advantages of small size and high power. To date, a variety of fundamental materials and ingenious structural designs have been proposed to achieve efficient droplet-based energy harvesting. The research and application of DENG in various fields have received widespread attention. In this review, we focus on the fundamental mechanism and recent progress of droplet-based nanogenerators in the following three aspects: droplet properties, energy harvesting and self-powered sensing. Finally, some challenges and further outlook for droplet-based nanogenerators are discussed to boost the future development of this promising field.
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Affiliation(s)
- Jianing Dong
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Tan Kah Kee Innovation Laboratory, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
| | - Feng Ru Fan
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Tan Kah Kee Innovation Laboratory, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
| | - Zhong-Qun Tian
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Tan Kah Kee Innovation Laboratory, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
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69
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Hao S, Xie Z, Li Z, Kou J, Wu F. Initial-position-driven opposite directional transport of a water droplet on a wedge-shaped groove. NANOSCALE 2021; 13:15963-15972. [PMID: 34523632 DOI: 10.1039/d1nr03467g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The transport direction of water droplets on a functionalized surface is of great significance due to its wide applications in microfluidics technology. The prevailing view is that a water droplet on a wedge-shaped groove always moves towards the wider end. In this paper, however, molecular dynamics simulations show that a water droplet can move towards the narrower end if placed at specific positions. It is found that the direction of water droplet transport on a grooved surface is related to its initial position. The water droplet moves towards the wider end only when it is placed near the wider end initially. If the water droplet is placed near the narrower end, it will move in the opposite direction. The novel phenomenon is attributed to the opposite interactions of the groove substrate and the groove upper layers with water droplets. Two effective models are proposed to exploit the physical origin of different transport directions of water droplets on a wedge-shaped groove surface. The study provides an insight into the design of nanostructured surfaces to effectively control the droplet motion.
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Affiliation(s)
- Shaoqian Hao
- Institute of Theoretical Physics, State Key Laboratory of Quantum Optics and Quantum Optics Devices, Shanxi University, Taiyuan 030006, China
| | - Zhang Xie
- Department of Physics, Zhejiang Normal University, Jinhua 321004, China.
| | - Zheng Li
- School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Jianlong Kou
- Department of Physics, Zhejiang Normal University, Jinhua 321004, China.
| | - Fengmin Wu
- Institute of Theoretical Physics, State Key Laboratory of Quantum Optics and Quantum Optics Devices, Shanxi University, Taiyuan 030006, China
- Department of Physics, Zhejiang Normal University, Jinhua 321004, China.
- Department of Physics, Zhejiang Sci-Tech University, Hangzhou 310018, China.
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70
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Feng S, Zhu P, Zheng H, Zhan H, Chen C, Li J, Wang L, Yao X, Liu Y, Wang Z. Three-dimensional capillary ratchet-induced liquid directional steering. Science 2021; 373:1344-1348. [PMID: 34529472 DOI: 10.1126/science.abg7552] [Citation(s) in RCA: 112] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
[Figure: see text].
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Affiliation(s)
- Shile Feng
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong SAR 999077, P. R. China.,Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116024, P. R. China
| | - Pingan Zhu
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong SAR 999077, P. R. China
| | - Huanxi Zheng
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong SAR 999077, P. R. China
| | - Haiyang Zhan
- Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116024, P. R. China
| | - Chen Chen
- Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116024, P. R. China
| | - Jiaqian Li
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong SAR 999077, P. R. China
| | - Liqiu Wang
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong SAR 999077, P. R. China
| | - Xi Yao
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong SAR 999077, P. R. China
| | - Yahua Liu
- Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116024, P. R. China
| | - Zuankai Wang
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong SAR 999077, P. R. China.,Center for Nature-Inspired Engineering, City University of Hong Kong, Hong Kong SAR 999077, P. R. China
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71
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Aerodynamics-assisted, efficient and scalable kirigami fog collectors. Nat Commun 2021; 12:5484. [PMID: 34531392 PMCID: PMC8445985 DOI: 10.1038/s41467-021-25764-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Accepted: 08/13/2021] [Indexed: 11/29/2022] Open
Abstract
To address the global water shortage crisis, one of the promising solutions is to collect freshwater from the environmental resources such as fog. However, the efficiency of conventional fog collectors remains low due to the viscous drag of fog-laden wind deflected around the collecting surface. Here, we show that the three-dimensional and centimetric kirigami structures can control the wind flow, forming quasi-stable counter-rotating vortices. The vortices regulate the trajectories of incoming fog clusters and eject extensive droplets to the substrate. As the characteristic structural length is increased to the size of vortices, we greatly reduce the dependence of fog collection on the structural delicacy. Together with gravity-directed gathering by the folds, the kirigami fog collector yields a collection efficiency of 16.1% at a low wind speed of 0.8 m/s and is robust against surface characteristics. The collection efficiency is maintained even on a 1 m2 collector in an outdoor setting. Water shortage not only occurs in arid regions, but also in humid area with little precipitation, despite abundant fog. Authors develop robust and scalable 3D centimetric kirigami structures to control wind flow and regulate the trajectories of incoming fog, yielding high fog collection efficiency.
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72
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Cheng Y, Wang M, Sun J, Liu M, Du B, Liu Y, Jin Y, Wen R, Lan Z, Zhou X, Ma X, Wang Z. Rapid and Persistent Suction Condensation on Hydrophilic Surfaces for High-Efficiency Water Collection. NANO LETTERS 2021; 21:7411-7418. [PMID: 34176267 DOI: 10.1021/acs.nanolett.1c01928] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Water collection by dew condensation emerges as a sustainable solution to water scarcity. However, the transient condensation process that involves droplet nucleation, growth, and transport imposes conflicting requirements on surface properties. It is challenging to satisfy all benefits for different condensation stages simultaneously. By mimicking the structures and functions of moss Rhacocarpus, here, we report the attainment of dropwise condensation for efficient water collection even on a hydrophilic surface gated by a liquid suction mechanism. The Rhacocarpus-inspired porous surface (RIPS), which possesses a three-level wettability gradient, facilitates a rapid, directional, and persistent droplet suction. Such suction condensation enables a low nucleation barrier, frequent surface refreshing, and well-defined maximum droplet shedding radius simultaneously. Thus, a maximum ∼160% enhancement in water collection performance compared to the hydrophobic surface is achieved. Our work provides new insights and a design route for developing engineered materials for a wide range of water-harvesting and phase-change heat-transfer applications.
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Affiliation(s)
- Yaqi Cheng
- State Key Laboratory of Fine Chemicals, Liaoning Key Laboratory of Clean Utilization of Chemical Resources, Institute of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong 999077, China
| | - Mingmei Wang
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong 999077, China
| | - Jing Sun
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong 999077, China
| | - Minjie Liu
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong 999077, China
| | - Bingang Du
- State Key Laboratory of Fine Chemicals, Liaoning Key Laboratory of Clean Utilization of Chemical Resources, Institute of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Yuanbo Liu
- State Key Laboratory of Fine Chemicals, Liaoning Key Laboratory of Clean Utilization of Chemical Resources, Institute of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Yuankai Jin
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong 999077, China
| | - Rongfu Wen
- State Key Laboratory of Fine Chemicals, Liaoning Key Laboratory of Clean Utilization of Chemical Resources, Institute of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Zhong Lan
- State Key Laboratory of Fine Chemicals, Liaoning Key Laboratory of Clean Utilization of Chemical Resources, Institute of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Xiaofeng Zhou
- Shanghai Key Laboratory of Multidimensional Information Processing, School of Communication and Electronic Engineering, East China Normal University, Shanghai 200241, China
| | - Xuehu Ma
- State Key Laboratory of Fine Chemicals, Liaoning Key Laboratory of Clean Utilization of Chemical Resources, Institute of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Zuankai Wang
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong 999077, China
- Research Center for Nature-Inspired Engineering, City University of Hong Kong, Hong Kong 999077, China
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73
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Pan W, Wu S, Huang L, Song J. Large-area fabrication of superhydrophobic micro-conical pillar arrays on various metallic substrates. NANOSCALE 2021; 13:14023-14034. [PMID: 34477683 DOI: 10.1039/d1nr02924j] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Superhydrophobic micro-conical pillar arrays have huge application prospects, from anti-icing to oil/water separation, corrosion resistance, and water droplet manipulation. However, there is still a lack of versatile methods with high processing efficiency to fabricate superhydrophobic micro-conical pillar arrays on various metallic substrates. Herein, a nanosecond laser ablation technology with versatility and high processing efficiency was developed to fabricate large-area superhydrophobic micro-conical pillar arrays. The simulation and experiments indicated that the height and the pillar inclination angle of micro-conical pillars could be easily controlled by adjusting the nanosecond laser parameters or the tilted angles of metallic substrates. The fabricated superhydrophobic micro-conical pillar arrays not only showed good mechanical robustness and chemical stability but also easily reduced the contact time for an impinging water droplet, showing potential application prospects in anti-icing from freezing rain. This kind of method with versatility and high processing efficiency will promote the practical applications of superhydrophobic micro-conical arrays.
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Affiliation(s)
- Weihao Pan
- Key Laboratory for Precision and Non-traditional Machining Technology of the Ministry of Education, Dalian University of Technology, Dalian 116024, P. R. China.
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74
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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: 3] [Impact Index Per Article: 1.0] [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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75
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Hu S, Cao X, Reddyhoff T, Shi X, Peng Z, deMello AJ, Dini D. Flexibility-Patterned Liquid-Repelling Surfaces. ACS APPLIED MATERIALS & INTERFACES 2021; 13:29092-29100. [PMID: 34078079 DOI: 10.1021/acsami.1c05243] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Droplets impacting solid surfaces is ubiquitous in nature and of practical importance in numerous industrial applications. For liquid-repelling applications, rigidity-based asymmetric redistribution and flexibility-based structural oscillation strategies have been proven on artificial surfaces; however, these are limited by strict impacting positioning. Here, we show that the gap between these two strategies can be bridged by a flexibility-patterned design similar to a trampoline park. Such a flexibility-patterned design is realized by three-dimensional projection micro-stereolithography and is shown to enhance liquid repellency in terms of droplet impalement resistance and contact time reduction. This is the first demonstration of the synergistic effect obtained by a hybrid solution that exploits asymmetric redistribution and structural oscillation in liquid-repelling applications, paving the rigidity-flexibility cooperative way of wettability tuning. Also, the flexibility-patterned surface is applied to accelerate liquid evaporation.
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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, U.K
| | - 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, U.K
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76
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Li P, Xu X, Yu Y, Wang L, Ji B. Biased Motions of a Droplet on the Inclined Micro-conical Superhydrophobic Surface. ACS APPLIED MATERIALS & INTERFACES 2021; 13:27687-27695. [PMID: 34100284 DOI: 10.1021/acsami.1c07209] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Anisotropic superhydrophobic surfaces that have many superior properties, such as directional self-cleaning, droplet transport, heat transfer, and so on, are widely used in various fields. Different from symmetric surfaces, a water droplet often shows directional spreading, moving, and bouncing on asymmetric surfaces. To investigate the mechanisms and achieve controllability of droplet motions on asymmetric surfaces, a series of surfaces with inclined micro-conical arrays are fabricated by integrating the methods of soft lithography, hot-pressing, and crystal growth. We found that the droplet would spread along the reverse direction of micro-cone's orientation but bounce and detach off the surface and move toward the direction of micro-cone's orientation. To understand these interesting performances, a mathematical model is established from the perspective of force balance, and a series of numerical simulations are performed. Additionally, the relationship between the droplet motions and the micro-structural parameters, including the inclined angle, line space, and height, are studied. This work may provide useful insights into droplet controlling, anisotropic surface designing, and its applications.
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Affiliation(s)
- Peiliu Li
- Biomechanics and Biomaterials Laboratory, Department of Mechanics, School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Xiangyu Xu
- Biomechanics and Biomaterials Laboratory, Department of Mechanics, School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yang Yu
- Biomechanics and Biomaterials Laboratory, Department of Mechanics, School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - 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
| | - Baohua Ji
- Biomechanics and Biomaterials Laboratory, Department of Engineering Mechanics, Zhejiang University, Hangzhou 310027, China
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77
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Li S, Fan Y, Liu Y, Niu S, Han Z, Ren L. Smart Bionic Surfaces with Switchable Wettability and Applications. JOURNAL OF BIONIC ENGINEERING 2021; 18:473-500. [PMID: 34131422 PMCID: PMC8193597 DOI: 10.1007/s42235-021-0038-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In order to satisfy the needs of different applications and more complex intelligent devices, smart control of surface wettability will be necessary and desirable, which gradually become a hot spot and focus in the field of interface wetting. Herein, we review interfacial wetting states related to switchable wettability on superwettable materials, including several classical wetting models and liquid adhesive behaviors based on the surface of natural creatures with special wettability. This review mainly focuses on the recent developments of the smart surfaces with switchable wettability and the corresponding regulatory mechanisms under external stimuli, which is mainly governed by the transformation of surface chemical composition and geometrical structures. Among that, various external stimuli such as physical stimulation (temperature, light, electric, magnetic, mechanical stress), chemical stimulation (pH, ion, solvent) and dual or multi-triggered stimulation have been sought out to realize the regulation of surface wettability. Moreover, we also summarize the applications of smart surfaces in different fields, such as oil/water separation, programmable transportation, anti-biofouling, detection and delivery, smart soft robotic etc. Furthermore, current limitations and future perspective in the development of smart wetting surfaces are also given. This review aims to offer deep insights into the recent developments and responsive mechanisms in smart biomimetic surfaces with switchable wettability under external various stimuli, so as to provide a guidance for the design of smart surfaces and expand the scope of both fundamental research and practical applications.
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Affiliation(s)
- Shuyi Li
- Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun, 130022 China
| | - Yuyan Fan
- Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun, 130022 China
| | - Yan Liu
- Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun, 130022 China
| | - Shichao Niu
- Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun, 130022 China
| | - Zhiwu Han
- Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun, 130022 China
| | - Luquan Ren
- Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun, 130022 China
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78
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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: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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79
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Liu M, Du H, Cheng Y, Zheng H, Jin Y, To S, Wang S, Wang Z. Explosive Pancake Bouncing on Hot Superhydrophilic Surfaces. ACS APPLIED MATERIALS & INTERFACES 2021; 13:24321-24328. [PMID: 33998790 DOI: 10.1021/acsami.1c05867] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The rapid detachment of liquid droplets from engineered surfaces in the form of complete rebound, pancake bouncing, or trampolining has been extensively studied over the past decade and is of practical importance in many industrial processes such as self-cleaning, anti-icing, energy conversion, and so on. The spontaneous trampolining of droplets needs an additional low-pressure environment and the manifestation of pancake bouncing on superhydrophobic surfaces requires meticulous control of macrotextures and impacting velocity. In this work, we report that the rapid pancake-like levitation of impinging droplets can be achieved on superhydrophilic surfaces through the application of heating. In particular, we discovered explosive pancake bouncing on hot superhydrophilic surfaces made of hierarchically non-interconnected honeycombs, which is in striking contrast to the partial levitation of droplets on the surface consisting of interconnected microposts. This enhanced droplet bouncing phenomenon, characterized by a significant reduction in contact time and increase in the bouncing height, is ascribed to the production and spatial confinement of pressurized vapor in non-interconnected structures. The manifestation of pancake bouncing on the superhydrophilic surface rendered by a bottom-to-up boiling process may find promising applications such as the removal of trapped solid particles.
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Affiliation(s)
- Minjie Liu
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China
| | - Hanheng Du
- State Key Laboratory of Ultra-precision Machining Technology, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong 999077, China
| | - Yaqi Cheng
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China
| | - Huanxi Zheng
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China
| | - Yuankai Jin
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China
| | - Suet To
- State Key Laboratory of Ultra-precision Machining Technology, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong 999077, China
| | - Steven Wang
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China
| | - Zuankai Wang
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China
- Research Center for Nature-Inspired Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China
- Shenzhen Research Institute of City University of Hong Kong, Shenzhen 518057, China
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80
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Ji J, Jiao Y, Song Q, Zhang Y, Liu X, Liu K. Bioinspired Geometry-Gradient Metal Slippery Surface by One-Step Laser Ablation for Continuous Liquid Directional Self-Transport. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:5436-5444. [PMID: 33899490 DOI: 10.1021/acs.langmuir.1c00911] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Liquid directional self-transport on the functional surface plays an important role in both industrial and academic fields. Inspired by the natural cactus spine and pitcher plant, we have successfully designed a kind of geometry-gradient slippery surface (GGSS) based on aluminum alloy materials which could actively achieve directional self-movement and also antigravity self-movement of various liquid droplets by topography gradient. The mechanism of liquid directional self-transport was theoretically explored through the mechanical analysis of the triple contact line, which was mainly related to the competition between the driven force induced by Laplace pressure and the adhesive force induced by viscous resistance. The adhesive force between the droplet and the surface was quantitatively measured using a homemade experimental apparatus and the results showed that the lateral adhesive force on the GGSS is much smaller than that on the original surface. Additionally, a series of quantitative experiments were conducted to explore the influence of droplet volume and vertex angle on the transport distance and velocity. Finally, we achieved the antigravity self-transport of the droplet on the inclined GGSS to further verify the self-transport ability of the GGSS. We believe that the proposed GGSS with liquid directional self-transport ability in the present work would provide some potential opportunities in modern tribo-systems to optimize the lubricating qualities, especially the lubrication and friction at the extreme contact interface.
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Affiliation(s)
- Jiawei Ji
- Institute of Tribology, School of Mechanical Engineering, Hefei University of Technology, Hefei 230009, China
| | - Yunlong Jiao
- Institute of Tribology, School of Mechanical Engineering, Hefei University of Technology, Hefei 230009, China
| | - Qingrui Song
- Institute of Tribology, School of Mechanical Engineering, Hefei University of Technology, Hefei 230009, China
| | - Yan Zhang
- Institute of Tribology, School of Mechanical Engineering, Hefei University of Technology, Hefei 230009, China
| | - Xiaojun Liu
- Institute of Tribology, School of Mechanical Engineering, Hefei University of Technology, Hefei 230009, China
| | - Kun Liu
- Institute of Tribology, School of Mechanical Engineering, Hefei University of Technology, Hefei 230009, China
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81
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Li J, Zhou X, Tao R, Zheng H, Wang Z. Directional Liquid Transport from the Cold Region to the Hot Region on a Topological Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:5059-5065. [PMID: 33860666 DOI: 10.1021/acs.langmuir.1c00627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Manifested from the "tears of wine" to the "coffee-ring effect", the directional transport of a liquid governed by the Marangoni effect is highly pervasive in our daily life and has brought a great number of applications. Similar to this surface tension gradient-dominated process, the fluid preferentially flows from the hot region to the cold region. In contrast to this perception, in this study, we report that water liquid deposited on a specially designed topological surface can flow from the low-temperature region to the high-temperature region in a spontaneous, long-range, and unidirectional manner. We show that such a behavior is mainly owing to a strong topological effect that outweighs the thermal gradient imposed along the surface. Moreover, the specific temperature range applied on the topological surface for the occurrence of such a unidirectional liquid transport phenomenon is also identified. Our findings would find important insights for developing next-generation cooling devices where a rapid flow from the condensation region to the evaporation/boiling region is preferred.
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Affiliation(s)
- Jiaqian Li
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong 999077, China
| | - Xiaofeng Zhou
- Shanghai Key Laboratory of Multidimensional Information Processing, Department of Electronic Engineering, East China Normal University, Shanghai 200241, China
| | - Ran Tao
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong 999077, China
| | - Huanxi Zheng
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong 999077, China
| | - Zuankai Wang
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong 999077, China
- Shenzhen Research Institute of City University of Hong Kong, Shenzhen 518000, China
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82
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Zhang F, Ge W, Wang C, Zheng X, Wang D, Zhang X, Wang X, Xue X, Qing G. Highly Strong and Solvent-Resistant Cellulose Nanocrystal Photonic Films for Optical Coatings. ACS APPLIED MATERIALS & INTERFACES 2021; 13:17118-17128. [PMID: 33793208 DOI: 10.1021/acsami.1c02753] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Cellulose nanocrystals (CNCs) are powerful photonic building blocks for the fabrication of biosourced colored films. A combination of the advantages of self-assembled CNCs and multiple templating agents offers access to the development of novel physicochemical sensors, structural coatings, and optic devices. However, due to the inherent brittleness and water instability of CNC-derived materials, their further applications are widely questionable and restrictive. Here, a soft polymer of poly(vinyl alcohol) (PVA) was introduced into the rigid CNC system to balance molecular interactions, whereafter two hard/soft nanocomposites were fastened through a cross-linking reaction of glutaraldehyde (GA), resulting in a highly flexible, water-stable, and chiral nematic CNC composite film through an evaporation-induced self-assembly technique. For a 1.5 wt % GA-cross-linked 70 wt % CNC loading film, its treatment with harsh hydrophilic exposure (soaking in a strong acid, strong base, and seawater) and various organic solvents show exceptional solvent-resistant abilities. Furthermore, the film can even withstand a weight of 167 g cm-2 without failure, which is a highly stiff and durable character. Importantly, the film remains a highly ordered chiral nematic organization, being able to act as a highly transparent substrate for selective reflection of left-handed circularly polarized light, preparing fully covered and patterned full-color coatings on various substrates. Our work paves the way for applications in low-cost, durable, and photonic cellulosic coatings.
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Affiliation(s)
- Fusheng Zhang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Wenna Ge
- School of Mechanical Engineering, Dalian University of Technology, Dalian 116024, P. R. China
| | - Cunli Wang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
| | - Xintong Zheng
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
| | - Dongdong Wang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
| | - Xiancheng Zhang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
| | - Xue Wang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
| | - Xingya Xue
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Guangyan Qing
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
- Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), College of Chemistry, Nankai University, Tianjin 300071, P. R. China
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83
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Du B, Cheng Y, Yang S, Xu W, Lan Z, Wen R, Ma X. Preferential Vapor Nucleation on Hierarchical Tapered Nanowire Bunches. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:774-784. [PMID: 33382946 DOI: 10.1021/acs.langmuir.0c03125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Controlling vapor nucleation on micro-/nanostructured surfaces is critical to achieving exciting droplet dynamics and condensation enhancement. However, the underlying mechanism of nucleation phenomena remains unclear because of its nature of nanoscale and transience, especially for the complex-structured surfaces. Manipulating vapor nucleation via the rational surface design of micro-/nanostructures is extremely challenging. Here, we fabricate hierarchical surfaces comprising tapered nanowire bunches and crisscross microgrooves. Nanosteps are formed around the top of the nanowire bunches, where the nanowires all around agglomerate densely because of surface tension. The theoretical analysis and molecular dynamics simulation show that nanostep morphologies that are around the top of the nanowire bunches can enable a lower energy barrier and a higher nucleation capability than those of the sparsely packed nanowires at the center and bottom of the nanowire bunches. Vapor condensation experiments demonstrate that the nucleation preferentially occurs around the top of the nanowire bunches. The results provide guidelines to design micro-/nanostructures for promoting vapor nucleation and droplet removal in condensation.
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Affiliation(s)
- Bingang Du
- State Key Laboratory of Fine Chemicals, Liaoning Key Laboratory of Clean Utilization of Chemical Resources, Institute of Chemical Engineering, Dalian University of Technology, Dalian 116024, PR China
| | - Yaqi Cheng
- State Key Laboratory of Fine Chemicals, Liaoning Key Laboratory of Clean Utilization of Chemical Resources, Institute of Chemical Engineering, Dalian University of Technology, Dalian 116024, PR China
| | - Siyan Yang
- State Key Laboratory of Fine Chemicals, Liaoning Key Laboratory of Clean Utilization of Chemical Resources, Institute of Chemical Engineering, Dalian University of Technology, Dalian 116024, PR China
| | - Wei Xu
- State Key Laboratory of Fine Chemicals, Liaoning Key Laboratory of Clean Utilization of Chemical Resources, Institute of Chemical Engineering, Dalian University of Technology, Dalian 116024, PR China
| | - Zhong Lan
- State Key Laboratory of Fine Chemicals, Liaoning Key Laboratory of Clean Utilization of Chemical Resources, Institute of Chemical Engineering, Dalian University of Technology, Dalian 116024, PR China
| | - Rongfu Wen
- State Key Laboratory of Fine Chemicals, Liaoning Key Laboratory of Clean Utilization of Chemical Resources, Institute of Chemical Engineering, Dalian University of Technology, Dalian 116024, PR China
| | - Xuehu Ma
- State Key Laboratory of Fine Chemicals, Liaoning Key Laboratory of Clean Utilization of Chemical Resources, Institute of Chemical Engineering, Dalian University of Technology, Dalian 116024, PR China
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84
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Dai L, Lin D, Wang X, Jiao N, Liu L. Integrated Assembly and Flexible Movement of Microparts Using Multifunctional Bubble Microrobots. ACS APPLIED MATERIALS & INTERFACES 2020; 12:57587-57597. [PMID: 33301292 DOI: 10.1021/acsami.0c17518] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Industrial robots have been widely used for manufacturing and assembly in factories. However, at the microscale, most assembly technologies can only pattern the micromodules together loosely and can hardly combine the micromodules to directly form an entity that cannot be easily dispersed. In this study, surface bubbles are made to function as microrobots on a chip. These microrobots can move, fix, lift, and drop microparts and integratively assemble them into a tightly connected entity. As an example, the assembly of a pair of microparts with dovetails is considered. A jacklike bubble robot is used to lift and drop a micropart with a tail, whereas a mobile microrobot is used to push the other micropart with the corresponding socket to the proper position so that the tail can be inserted into the socket. The assembled microparts with the tail-socket joint can move as an entity without separation. Similarly, different types of parts are integratively assembled to form various structures such as gears, snake-shaped chains, and vehicles, which are then driven by bubble microrobots to perform different forms of movement. This assembly technology is simple and efficient and is expected to play an important role in micro-operation, modular assembly, and tissue engineering.
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Affiliation(s)
- Liguo Dai
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016, China
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110016, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Daojing Lin
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016, China
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110016, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaodong Wang
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016, China
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110016, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Niandong Jiao
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016, China
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110016, China
| | - Lianqing Liu
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016, China
- Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110016, China
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85
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Chen Y, Liu J, Song J, Liu R, Zhao D, Hua S, Lu Y. Energy conversion based on superhydrophobic surfaces. Phys Chem Chem Phys 2020; 22:25430-25444. [PMID: 33169125 DOI: 10.1039/d0cp04257a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Covering about 70% of the earth's surface, water contains considerable energy that remains unexploited. Superhydrophobic surfaces (SHSs) possess excellent water repellency, and energy conversion based on SHSs has opened up a new avenue for efficient collection and utilization of water energy. Therefore, it is of great significance to efficiently prepare SHSs and apply them for energy conversion in different fields. In this review, we first summarize the fabrication methods of SHSs, and then provide an overview of the energy conversion forms based on SHSs. Finally, the related applications corresponding to the energy conversion forms are introduced, including renewable energy collection and utilization, wearable device design, use of liquid sensors, surface cooling and heat dissipation, self-propelled devices, droplet manipulation and lab-on-a-chip devices; and their challenges and future perspectives are highlighted.
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Affiliation(s)
- Yang Chen
- School of Mechanical Engineering, Dalian University of Technology, Dalian, 116024, P. R. China.
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86
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Yan X, Qin Y, Chen F, Zhao G, Sett S, Hoque MJ, Rabbi KF, Zhang X, Wang Z, Li L, Chen F, Feng J, Miljkovic N. Laplace Pressure Driven Single-Droplet Jumping on Structured Surfaces. ACS NANO 2020; 14:12796-12809. [PMID: 33052666 DOI: 10.1021/acsnano.0c03487] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Droplet transport on, and shedding from, surfaces is ubiquitous in nature and is a key phenomenon governing applications including biofluidics, self-cleaning, anti-icing, water harvesting, and electronics thermal management. Conventional methods to achieve spontaneous droplet shedding enabled by surface-droplet interactions suffer from low droplet transport velocities and energy conversion efficiencies. Here, by spatially confining the growing droplet and enabling relaxation via rationally designed grooves, we achieve single-droplet jumping of micrometer and millimeter droplets with dimensionless jumping velocities v* approaching 0.95, significantly higher than conventional passive approaches such as coalescence-induced droplet jumping (v* ≈ 0.2-0.3). The mechanisms governing single-droplet jumping are elucidated through the study of groove geometry and local pinning, providing guidelines for optimized surface design. We show that rational design of grooves enables flexible control of droplet-jumping velocity, direction, and size via tailoring of local pinning and Laplace pressure differences. We successfully exploit this previously unobserved mechanism as a means for rapid removal of droplets during steam condensation. Our study demonstrates a passive method for fast, efficient, directional, and surface-pinning-tolerant transport and shedding of droplets having micrometer to millimeter length scales.
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Affiliation(s)
- Xiao Yan
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Yimeng Qin
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Feipeng Chen
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Guanlei Zhao
- Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
| | - Soumyadip Sett
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Muhammad Jahidul Hoque
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Kazi Fazle Rabbi
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Xueqian Zhang
- Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
| | - Zi Wang
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Longnan Li
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Feng Chen
- Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
| | - Jie Feng
- 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
- Department of 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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87
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Abstract
Various creatures, such as spider silk and cacti, have harnessed their surface structures to collect fog for survival. These surfaces typically stay dry and have a large contact hysteresis enabling them to move a condensed water droplet, resulting in an intermittent transport state and a relatively reduced speed. In contrast to these creatures, here we demonstrate that Nepenthes alata offers a remarkably integrated system on its peristome surface to harvest water continuously in a humid environment. Multicurvature structures are equipped on the peristome to collect and transport water continuously in three steps: nucleation of droplets on the ratchet teeth, self-pumping of water collection that steadily increases by the concavity, and transport of the acquired water to overflow the whole arch channel of the peristome. The water-wetted peristome surface can further enhance the water transport speed by ∼300 times. The biomimetic design expands the application fields in water and organic fogs gathering to the evaporation tower, laboratory, kitchen, and chemical industry.
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88
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Shi Z, Lai X, Sun C, Zhang X, Zhang L, Pu Z, Wang R, Yu H, Li D. Step emulsification in microfluidic droplet generation: mechanisms and structures. Chem Commun (Camb) 2020; 56:9056-9066. [DOI: 10.1039/d0cc03628e] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Step emulsification for micro- and nano-droplet generation is reviewed in brief, including the emulsion mechanisms and microfluidic devices.
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Affiliation(s)
- Zhi Shi
- State Key Laboratory of Precision Measuring Technology and Instruments
- Tianjin University
- Tianjin
- China
| | - Xiaochen Lai
- State Key Laboratory of Precision Measuring Technology and Instruments
- Tianjin University
- Tianjin
- China
| | - Chengtao Sun
- State Key Laboratory of Precision Measuring Technology and Instruments
- Tianjin University
- Tianjin
- China
| | - Xingguo Zhang
- State Key Laboratory of Precision Measuring Technology and Instruments
- Tianjin University
- Tianjin
- China
| | - Lei Zhang
- State Key Laboratory of Precision Measuring Technology and Instruments
- Tianjin University
- Tianjin
- China
| | - Zhihua Pu
- State Key Laboratory of Precision Measuring Technology and Instruments
- Tianjin University
- Tianjin
- China
| | - Ridong Wang
- State Key Laboratory of Precision Measuring Technology and Instruments
- Tianjin University
- Tianjin
- China
| | - Haixia Yu
- Tianjin Key Laboratory of Biomedical Detecting Techniques and Instruments
- Tianjin University
- Tianjin
- China
| | - Dachao Li
- State Key Laboratory of Precision Measuring Technology and Instruments
- Tianjin University
- Tianjin
- China
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