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Ma H, Jiang Z, Yuan C, Cheng C, Wu J, Zhong Y, Tie J, Gao F, Zhan X, Zhang Q. Dynamical Adsorption Behavior Prediction of Dried Tobacco Leaf Heterogeneous Interfaces through Simulation and Image Recognition Techniques. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:19195-19208. [PMID: 39192631 DOI: 10.1021/acs.langmuir.4c02358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/29/2024]
Abstract
The process of spraying water and flavorings on dry tobacco is an important factor in the industrial environment and product quality. Tobacco as a complex porous fiber material, the interfacial transfer process of water is complex. In this study, machine learning and image recognition techniques were utilized to quickly obtain the structural parameters of the tobacco surface and construct a cellular structure model of the tobacco surface. In situ observation of the droplet impact spreading process was carried out using a high-speed camera to explore the droplet dissipation dynamics on different surfaces. And the competing processes of droplet wetting and evaporation under the influence of surface microstructure were determined by combining experimental studies and finite element simulation calculations. Based on the characteristics of tobacco pore size distribution, the infiltration under gas-liquid two-phase action was transformed into single-phase flow transfer under capillary force, and the continuous droplet infiltration process was simulated. A parallel artificial membrane permeability measurement method of bionic tobacco waxy layer was constructed for the screening of spray dosing copenetrant. This study brings new insights into the wetting of porous fibrous materials and is important for exploring the wetting process and additive development process influenced by the microstructure.
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Affiliation(s)
- Haowei Ma
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027, China
| | - Zhiqin Jiang
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027, China
| | - Chunbo Yuan
- Zhejiang China Tobacco Industry Company Limited, Ningbo 315000, China
| | - Changhe Cheng
- Zhejiang China Tobacco Industry Company Limited, Ningbo 315000, China
| | - Jian Wu
- Zhejiang China Tobacco Industry Company Limited, Ningbo 315000, China
| | - Yongjian Zhong
- Zhejiang China Tobacco Industry Company Limited, Ningbo 315000, China
| | - Jinxin Tie
- Zhejiang China Tobacco Industry Company Limited, Ningbo 315000, China
| | - Feng Gao
- Zhejiang Provincial Innovation Center of Advanced Chemicals Technology, Institute of Zhejiang University-Quzhou, Quzhou 324000, China
| | - Xiaoli Zhan
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027, China
- Zhejiang Provincial Innovation Center of Advanced Chemicals Technology, Institute of Zhejiang University-Quzhou, Quzhou 324000, China
| | - Qinghua Zhang
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027, China
- Zhejiang Provincial Innovation Center of Advanced Chemicals Technology, Institute of Zhejiang University-Quzhou, Quzhou 324000, China
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Kumar P, Harvie DJE. Energy Dissipation during Wenzel Wetting via Roughness Scale Interface Dynamics. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:16190-16207. [PMID: 39049496 DOI: 10.1021/acs.langmuir.4c01292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
A numerical method is proposed to simulate the roughness scale interface dynamics of a slow-moving fluid interface as it advances over a chemically homogeneous rough surface. Analysis of the governing augmented Navier-Stokes and Young's boundary condition equations shows how the local interface behavior can be represented via a series of incrementally advanced equilibrium interfacial morphologies. Combined with a roughness scale mechanical energy balance [Harvie, D. J. E. Contact-angle hysteresis on rough surfaces: mechanical energy balance framework. J. Fluid Mech. 2024, 986, A17], the simulations are used to calculate the energy dissipation associated with a surface decorated with a periodic array of round-edge square pillars. This dissipation is used to predict static contact angle hysteresis (CAH) from knowledge of just the surface roughness topography and equilibrium contact angle. We show that the energy dissipated varies approximately as ϕln ϕ (with ϕ being the area fraction), becoming zero as ϕ → 0. The CAH predicted by our method is in good agreement with the experimental results of Forsberg et al. [Forsberg, P. S.; Priest, C.; Brinkmann, M.; Sedev, R.; Ralston, J. Contact line pinning on microstructured surfaces for liquids in the Wenzel state. Langmuir 2010, 26, 860-865], thereby demonstrating that our numerical method of simulating interfacial dynamics adequately captures the real interface motion, as well as illustrating how far-field contact angle and energy dissipation approaches are consistent for this surface. We also compute CAH for an interface moving at 45° to the surface periodicity direction to show that the experimental measurements are bracketed by the 0° and 45° advance direction results. The proposed method opens up the field to quantitative analysis, surface functionalization, and design for different specific applications.
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Affiliation(s)
- Pawan Kumar
- Multiphysics Fluid Dynamics Group, Department of Chemical Engineering, The University of Melbourne, Parkville, 3010 Victoria, Australia
| | - Dalton J E Harvie
- Multiphysics Fluid Dynamics Group, Department of Chemical Engineering, The University of Melbourne, Parkville, 3010 Victoria, Australia
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Fan Y, Wang S, Huang Y, Tan Y, Gui L, Huang S, Tian X. Unconventional Dually-Mobile Superrepellent Surfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2402893. [PMID: 38848582 DOI: 10.1002/adma.202402893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 05/19/2024] [Indexed: 06/09/2024]
Abstract
The ability of water droplets to move freely on superrepellent surfaces is a crucial feature that enables effective liquid repellency. Common superrepellent surfaces allow free motion of droplets in the Cassie state, with the liquid resting on the surface textures. However, liquid impalement into the textures generally leads to a wetting transition to the Wenzel state and droplet immobilization on the surface, thereby destroying the liquid repellency. This study reports the creation of a novel type of superrepellent surface through rational structural control combined with liquid-like surface chemistry, which allows for the free movement of water droplets and effective repellency in both the Cassie and Wenzel states. Theoretical guidelines for designing such surfaces are provided, and experimental results are consistent with theoretical analysis. Furthermore, this work demonstrates the enhanced ice resistance of the dually-mobile superrepellent surfaces, along with their distinctive self-cleaning capability to eliminate internal contaminants. This study expands the understanding of superrepellency and offers new possibilities for the development of repellent surfaces with exceptional anti-wetting properties.
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Affiliation(s)
- Yue Fan
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou, 510006, China
- Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, Guangzhou Key Laboratory of Flexible Electronic Materials and Wearable Devices, Sun Yat-sen University, Guangzhou, 510006, China
| | - Shuai Wang
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou, 510006, China
- Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, Guangzhou Key Laboratory of Flexible Electronic Materials and Wearable Devices, Sun Yat-sen University, Guangzhou, 510006, China
| | - Yusheng Huang
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou, 510006, China
- Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, Guangzhou Key Laboratory of Flexible Electronic Materials and Wearable Devices, Sun Yat-sen University, Guangzhou, 510006, China
| | - Yao Tan
- School of Integrated Circuit Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Lishuang Gui
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou, 510006, China
- Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, Guangzhou Key Laboratory of Flexible Electronic Materials and Wearable Devices, Sun Yat-sen University, Guangzhou, 510006, China
| | - Shilin Huang
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou, 510006, China
- Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, Guangzhou Key Laboratory of Flexible Electronic Materials and Wearable Devices, Sun Yat-sen University, Guangzhou, 510006, China
| | - Xuelin Tian
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou, 510006, China
- Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, Guangzhou Key Laboratory of Flexible Electronic Materials and Wearable Devices, Sun Yat-sen University, Guangzhou, 510006, China
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Kumar P, Mulvaney P, Harvie DJE. Energy dissipation during homogeneous wetting of surfaces with randomly and periodically distributed cylindrical pillars. J Colloid Interface Sci 2024; 659:105-118. [PMID: 38159487 DOI: 10.1016/j.jcis.2023.12.134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 12/12/2023] [Accepted: 12/20/2023] [Indexed: 01/03/2024]
Abstract
HYPOTHESIS Understanding contact angle hysteresis on rough surfaces is important as most industrially relevant and naturally occurring surfaces possess some form of random or structured roughness. We hypothesise that hysteresis can be described by the dilute defect model of Joanny & de Gennes [1] and that the energy dissipation occurring during the stick-slip motion of the contact line is key to developing a predictive equation for hysteresis. EXPERIMENTS We measured hysteresis on surfaces with randomly distributed and periodically arranged microscopic cylindrical pillars for a variety of different liquids in air. The inherent (flat surface) contact angles tested range from lyophilic (θe=33.8°) to lyophobic (θe=112.0°). FINDINGS A methodology for averaging the measured advancing and receding contact angles on random surfaces is presented. Based on these results correlations for roughness-induced energy dissipation are derived, and an equation for predicting the advancing and receding contact angles during homogeneous (Wenzel) wetting on random surfaces is presented. Equations that predict the onset of the alternate wetting conditions of hemiwicking, split-advancing, split-receding and heterogeneous (Cassie) wetting are also derived, thus defining the range of validity for the homogeneous wetting equation. A 'cluster' concept is proposed to explain the measurably higher hysteresis exhibited by structured surfaces compared to random surfaces.
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Affiliation(s)
- Pawan Kumar
- Multiphysics Fluid Dynamics Group, Department of Chemical Engineering, University of Melbourne, Parkville, Melbourne, 3010, Victoria, Australia
| | - Paul Mulvaney
- ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Melbourne, Parkville, Melbourne, 3010, Victoria, Australia
| | - Dalton J E Harvie
- Multiphysics Fluid Dynamics Group, Department of Chemical Engineering, University of Melbourne, Parkville, Melbourne, 3010, Victoria, Australia.
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Li Q, Liu Y, He B, Wen B. Sliding Behavior of Droplets on a Tilted Substrate with a Chemical Step. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:14487-14499. [PMID: 37782898 DOI: 10.1021/acs.langmuir.3c01401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
Controlling and predicting the motion of droplets on a heterogeneous substrate have received widespread attention. In this paper, we numerically simulate the droplet sliding through a "chemical step", that is, different wetting properties at two sides of the step, on a tilted substrate by the multiphase lattice Boltzmann method (LBM). Three kinds of equilibrium statuses are reproduced by observing the deformation of the droplet and the velocities of the front contact line. This study shows the droplet obtains a driving force to break through the step by deformation in the initial stage that the droplet is blocked. The droplet spreads to two sides along the step when the front end is blocked and is stretched after the front end is passed over the step. The lengths of the lateral spreading and the longitudinal stretching and the time required to pass over the step depend on the strength of the step. In the sliding process, the kinetic energy is converted into surface energy as the droplet is blocked, and the gravitational potential energy is converted into surface and kinetic energy following the droplet passes over the step. If the droplet can slide through the step, the more strength in the step, the more the gravitational potential energy is converted, and the more the surface energy increases. When the strength of the step is small, unbalanced Young's force hinders the contact line moving forward after the central part of the front end of the droplet breaks through the step. While the velocity of droplet sliding slows down with the increasing strength of the step, the unbalanced Young's force pushes the contact line forward against the resistance. These observations throw insight into the dynamics of the droplets sliding on a heterogeneous surface, which may facilitate potential applications like microfluidics and liquid transportation.
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Affiliation(s)
- Quanying Li
- School of Computer Science and Engineering, Guangxi Normal University, Guilin 541004, China
| | - Yangsha Liu
- School of Computer Science and Engineering, Guangxi Normal University, Guilin 541004, China
| | - Bing He
- School of Computer Science and Engineering, Guangxi Normal University, Guilin 541004, China
- Key Lab of Education Blockchain and Intelligent Technology, Ministry of Education, Guangxi Normal University, Guilin 541004, China
- Guangxi Key Lab of Multi-Source Information Mining & Security, Guangxi Normal University, Guilin 541004, China
| | - Binghai Wen
- School of Computer Science and Engineering, Guangxi Normal University, Guilin 541004, China
- Key Lab of Education Blockchain and Intelligent Technology, Ministry of Education, Guangxi Normal University, Guilin 541004, China
- Guangxi Key Lab of Multi-Source Information Mining & Security, Guangxi Normal University, Guilin 541004, China
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Peng HY, Liu BY, Lo CC, Chen LJ, Seemann R, Brinkmann M. De-wetting of evaporating drops on regular patterns of triangular posts. J Chem Phys 2023; 159:024704. [PMID: 37428066 DOI: 10.1063/5.0151236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 06/19/2023] [Indexed: 07/11/2023] Open
Abstract
Directional wicking and spreading of liquids can be achieved by regular micro-patterns of specifically designed topographic features that break the reflection symmetry of the underlying pattern. The present study aims to understand the formation and stability of wetting films during the evaporation of volatile liquid drops on surfaces with a micro-pattern of triangular posts arranged in a rectangular lattice. Depending on the density and aspect ratio of the posts, we observe either spherical-cap shaped drops with a mobile three-phase contact line or the formation of circular or angular drops with a pinned three-phase contact line. Drops of the latter class eventually evolve into a liquid film extending to the initial footprint of the drop and a shrinking cap-shaped drop sitting on the film. The drop evolution is controlled by the density and aspect ratio of the posts, while no influence of the orientation of the triangular posts on the contact line mobility becomes evident. Our experiments corroborate previous results of systematic numerical energy minimization, predicting that conditions for a spontaneous retraction of a wicking liquid film depend weakly on the orientation of the film edge relative to the micro-pattern.
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Affiliation(s)
- Hsuan-Yi Peng
- Department of Chemical Engineering, National Taiwan University, 10617 Taipei, Taiwan
| | - Bang-Yan Liu
- Department of Chemical Engineering, National Taiwan University, 10617 Taipei, Taiwan
| | - Chi-Chun Lo
- Department of Chemical Engineering, National Taiwan University, 10617 Taipei, Taiwan
| | - Li-Jen Chen
- Department of Chemical Engineering, National Taiwan University, 10617 Taipei, Taiwan
| | - Ralf Seemann
- Experimental Physics and Center of Biophysics, Saarland University, 66123 Saarbrücken, Germany
| | - Martin Brinkmann
- Experimental Physics and Center of Biophysics, Saarland University, 66123 Saarbrücken, Germany
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Hauer L, Cai Z, Skabeev A, Vollmer D, Pham JT. Phase Separation in Wetting Ridges of Sliding Drops on Soft and Swollen Surfaces. PHYSICAL REVIEW LETTERS 2023; 130:058205. [PMID: 36800444 DOI: 10.1103/physrevlett.130.058205] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 01/11/2023] [Indexed: 06/18/2023]
Abstract
Drops in contact with swollen, elastomeric substrates can induce a capillary mediated phase separation in wetting ridges. Using confocal microscopy, we visualize phase separation of oligomeric silicone oil from a cross-linked silicone network during steady-state sliding of water drops. We find an inverse relationship between the oil tip height and the drop sliding speed, which is rationalized by competing transport timescales of the oil molecules: separation rate versus drop-advection speed. Separation rates in highly swollen networks are as fast as diffusion in pure melts.
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Affiliation(s)
- Lukas Hauer
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, 40506 Kentucky, USA
| | - Zhuoyun Cai
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, 40506 Kentucky, USA
| | - Artem Skabeev
- Institute of Organic Chemistry and Macromolecular Chemistry, Friedrich Schiller University Jena, Lessingstrasse 8, 07743 Jena, Germany
| | - Doris Vollmer
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Jonathan T Pham
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, 40506 Kentucky, USA
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Investigation of Ti/Al2O3 + TiO2 and Ti + TiO2/Al2O3 + TiO2 hybrid coatings as protection of ultra-light Mg–(Li)–Al–RE alloys against corrosion. Sci Rep 2022; 12:19363. [DOI: 10.1038/s41598-022-23452-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 10/31/2022] [Indexed: 11/13/2022] Open
Abstract
AbstractLow corrosion resistance is a significant problem of magnesium alloys, particularly ultra-light magnesium-lithium alloys. Surface treatment is one way to improve their corrosion resistance. The paper presents the results of tests of Ti/Al2O3 + TiO2 and Ti + TiO2/Al2O3 + TiO2 coatings obtained in a hybrid process combining PVD and ALD methods and ALD coating of Al2O3 + TiO2 type obtained on AE42 (Mg–4Li–2RE) and LAE442 (Mg–4Li–4Al–2RE). Structural studies were performed using scanning and transmission electron microscopy (SEM and TEM), atomic force microscopy and EDS and XPS spectroscopic methods. Potentiodynamic tests and electrochemical impedance spectroscopy EIS in 0.05 M NaCl solution were performed to determine the electrochemical properties of the tested materials. Moreover, tests of surface wettability and tribological properties using the ball-on-disc method were performed. Based on the analysis of anodic polarisation curves and Tafel analysis, it was found that the Ti + TiO2/Al2O3 + TiO2 coating showed the best potentiodynamic properties on both substrates. In particular, on the magnesium-lithium substrate, the value of the polarisation resistance of this hybrid coating is Rpol = 14 × 103 Ω × cm2, and the value of the corrosion current is jcorr = 0.4 µA/cm2. For the uncoated LAE442 substrate, the polarisation resistance is Rpol = 1.05 × 103 Ω × cm2, and the corrosion current value is jcorr = 5.49 µA/cm2. This improvement is due to the synergistic effect of the combined PVD and ALD technologies. The study confirmed the impact of hybrid coatings on improving the anti-corrosion and tribological properties of ultra-light magnesium alloys.
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Umlandt M, Kopyshev A, Pasechnik SV, Zakharov AV, Lomadze N, Santer S. Light-Triggered Manipulations of Droplets All in One: Reversible Wetting, Transport, Splitting, and Merging. ACS APPLIED MATERIALS & INTERFACES 2022; 14:41412-41420. [PMID: 36006795 DOI: 10.1021/acsami.2c10710] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Here, we establish different ways of light-triggered droplet manipulation such as reversible wetting, splitting, merging, and transport. The unique features of our approach are that the changes in the wetting properties of microscopic droplets of isotropic (oil) or anisotropic (liquid crystalline) liquids adsorbed on photoswitchable films can be triggered just by application of soft optical stimuli, which lead to dynamical, reversible changes in the local morphology of the structured surfaces. The adaptive films consist of an azobenzene-containing surfactant ionically attached to oppositely charged polymer chains. Under exposure to irradiation with light, the azobenzene photoisomerizes between two states, nonpolar trans-isomer and polar cis-isomer, resulting in the corresponding changes in the surface energy and orientation of the surfactant tails at the interface. Additionally, the local increase in the surface temperature due to absorption of light by the azobenzene groups enables diverse processes of manipulation of the adsorbed small droplets, such as the reversible increase of the droplet basal area up to 5 times, anisotropic wetting during irradiation with modulated light, and precise partition of the droplet into many small pieces, which can then be merged on demand to the desired number of larger droplets. Moreover, using a moving focused light spot, we experimentally demonstrate and theoretically explain the locomotion of the droplet over macroscopic distances with a velocity of up to 150 μm·s-1. Our findings could lead to the ultimate application of a programmable workbench for manipulating and operating an ensemble of droplets, just using simple and gentle optical stimuli.
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Affiliation(s)
- Maren Umlandt
- Institute of Physics and Astronomy, University of Potsdam, Potsdam14476, Germany
| | - Alexey Kopyshev
- Institute of Physics and Astronomy, University of Potsdam, Potsdam14476, Germany
| | - Sergey V Pasechnik
- Laboratory of Molecular Acoustics, MIREA-Russian Technological University, Moscow119454, Russia
| | - Alexandre V Zakharov
- Saint Petersburg Institute for Machine Sciences, The Russian Academy of Sciences, Saint Petersburg199178, Russia
| | - Nino Lomadze
- Institute of Physics and Astronomy, University of Potsdam, Potsdam14476, Germany
| | - Svetlana Santer
- Institute of Physics and Astronomy, University of Potsdam, Potsdam14476, Germany
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10
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Jiang L, Cheng Y, Wang S, Xu Z, Zhao Y. Non-Fluorine Oil Repellency: How Low the Intrinsic Wetting Threshold Can Be for Roughness-Induced Contact Angle Amplification? LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:5857-5864. [PMID: 35481750 DOI: 10.1021/acs.langmuir.2c00478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Surface chemistries for realizing oil repellency are mostly based on perfluoro compounds (PFCs) owing to their low surface energy. However, PFCs are not sustainable because of their persistent and bioaccumulative properties, and their usage, even short-chain ones, has begun to be phased out. To date, studies on non-fluorine oil repellency have been extremely rare, and the obtained oil repellency has been limited. Here, we report the non-fluorine oil repellency of a coating prepared on a tightly woven plain-weave fabric through hydrolysis and polycondensation of difunctional chlorosilane. The coated fabric exhibited a contact angle of 119.0° for castor oil and 81.4° for hexadecane, as well as a contact angle of 51.9° for decane with a surface tension as low as γLV = 23.5 mN m-1. According to the standard ISO 14419:2010, oil repellency was rated Grade 6. The solid surface tension of the coating was calculated to be γSV = 22.1 mN m-1. Through the test of the difference in contact angles between rough and smooth surfaces, the intrinsic wetting threshold (θIWT) for such a surface chemistry was determined to be ranging from 8.9 to 14.5°. A study on the effects of surface morphologies suggests that the realization of an oil-repellency rating of 6 and a θIWT as low as 8.9-14.5° strongly depends on the roughness topographies. We hope that this study will be useful for the design─and our understanding─of non-fluorine oil repellency for applications including stain-resistant textiles and grease-resistant food packaging.
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Affiliation(s)
- Lianyi Jiang
- College of Textile and Clothing Engineering, Soochow University, Suzhou 215123, China
| | - Yan Cheng
- College of Textile and Clothing Engineering, Soochow University, Suzhou 215123, China
| | - Shanchi Wang
- College of Textile and Clothing Engineering, Soochow University, Suzhou 215123, China
| | - Zhiguang Xu
- China-Australia Institute for Advanced Materials and Manufacturing, Jiaxing University, Jiaxing 314001, China
| | - Yan Zhao
- College of Textile and Clothing Engineering, Soochow University, Suzhou 215123, China
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11
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Al Balushi KM, Sefiane K, Orejon D. Binary mixture droplet wetting on micro-structure decorated surfaces. J Colloid Interface Sci 2022; 612:792-805. [PMID: 35065463 DOI: 10.1016/j.jcis.2021.12.171] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 12/17/2021] [Accepted: 12/26/2021] [Indexed: 10/19/2022]
Abstract
Liquid surface tension as well as solid structure play a paramount role on the intimate wetting and non-wetting regimes and interactions between liquids droplets and solid substrates. We hypothesise that the coupling of these two variables, independently addressed in the past, eventually offer a wider range of understanding to the surface science and interfacial communities. In this work, intrinsically hydrophobic micro-pillared surfaces varying in the spacing between structures, and pure ethanol, pure water and their binary mixtures (as well as acetone-water and ethylene glycol-water mixtures) are utilised, accessing a wide range of substrate solid fractions and liquid surface tensions experimentally. Wettability measurements are carried out at different azimuthal directions to exemplify the wetting/non-wetting behaviour as well as the droplet asymmetry function of both liquid composition and structure spacing. Our findings reveal that high water concentration droplets, i.e., high surface tension fluids, sit in the Cassie-Baxter regime while partial non-wetting Wenzel or mixed-mode regimes with enhanced droplet asymmetry ensuing for medium and high ethanol concentrations, i.e., low surface tension fluids, below certain micropillar spacing. Beyond micropillar spacing s ≥ 40 µm, the impact of the surface structure on the droplet shape is negligible, and droplets adopt a similar contact angle and circular shape as on a flat smooth hydrophobic surface. Wetting and non-wetting regimes are then supported by classical wetting theories and equations. A wetting regime map for a wide range of surface tension fluids and/or their mixtures on a wide domain of solid fractions is then proposed.
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Affiliation(s)
- Khaloud Moosa Al Balushi
- Institute for Multiscale Thermofluids, School of Engineering, The University of Edinburgh, Edinburgh EH9 3FD, Scotland, UK; Department of Engineering, The University of Technology and Applied Sciences, Suhar 311, Oman
| | - Khellil Sefiane
- Institute for Multiscale Thermofluids, School of Engineering, The University of Edinburgh, Edinburgh EH9 3FD, Scotland, UK
| | - Daniel Orejon
- Institute for Multiscale Thermofluids, School of Engineering, The University of Edinburgh, Edinburgh EH9 3FD, Scotland, UK; International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
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12
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Wawryk MM, Turpin GA, Tabor RF. Surface defects on wrinkled PDMS induce droplet anisotropy. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.128317] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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13
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Zhu C, Liu J, Xing Y, Li M, Zhang R, Li G, Gui X. Investigation of adhesion behavior between reactive oily bubble and low-rank coal. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2021.127809] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Akbari R, Antonini C. Contact angle measurements: From existing methods to an open-source tool. Adv Colloid Interface Sci 2021; 294:102470. [PMID: 34186300 DOI: 10.1016/j.cis.2021.102470] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/18/2021] [Accepted: 06/18/2021] [Indexed: 12/19/2022]
Abstract
Contact angle measurement is an effective way to investigate solid surface properties. The introduction of low-cost digital cameras, as well as software and libraries for image analysis, has made contact angle measurement potentially accessible to every laboratory. In this review, we provide a comparison of the main methods developed to evaluate contact angle from digital images, including the so-called Young-Laplace method, the circle and polynomial fittings, as well as the mask method. All methods have been implemented and compared analyzing virtual and real drop images in an open-source software, Dropen, developed as an app in MATLAB environment. The code enables single image analysis evaluation, for the robust automatic identification of the contact points and contact angle evaluation, with the goal of minimizing user inputs, automatizing the process and facilitating measurements for all users, from less experienced to advanced wetting experts. Dropen and its code are made available at BOA, the Bicocca Open Access public repository, for use and further development.
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15
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Abstract
Herein we compare various preparation methods for thin ZIF-8 layers on a Cu substrate for application as a host material for omniphobic lubricant-infused surfaces. Such omniphobic surfaces can be used in thermal engineering applications, for example to achieve dropwise condensation or anti-fouling and anti-icing surface properties. For these applications, a thin, conformal, homogeneous, mechanically and chemically stable coating is essential. In this study, thin ZIF-8 layers were deposited on a Cu substrate by different routes, such as (i) electrochemical anodic deposition on a Zn-covered Cu substrate, (ii) doctor blade technique for preparation of a composite layer containing PVDF binder and ZIF-8, as well as (iii) doctor blade technique for preparation of a two-layer composite on the Cu substrate containing a PVDF-film and a ZIF-8 layer. The morphology and topography of the coatings were compared by using profilometry, XRD, SEM and TEM techniques. After infusion with a perfluorinated oil, the wettability of the surfaces was assessed by contact angle measurements, and advantages of each preparation method were discussed.
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16
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An experimental and numerical study of droplet spreading and imbibition on microporous membranes. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.126191] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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17
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Parihar V, Chakraborty S, Das S, Chakraborty S, DasGupta S. Role of anisotropic pinning and liquid properties during partial rebound of droplets on unidirectionally structured hydrophobic surfaces. Chem Eng Sci 2021. [DOI: 10.1016/j.ces.2020.116197] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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18
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Woźniak A, Walke W, Jakóbik-Kolon A, Ziębowicz B, Brytan Z, Adamiak M. The Influence of ZnO Oxide Layer on the Physicochemical Behavior of Ti6Al4V Titanium Alloy. MATERIALS 2021; 14:ma14010230. [PMID: 33466481 PMCID: PMC7796469 DOI: 10.3390/ma14010230] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 12/26/2020] [Accepted: 12/28/2020] [Indexed: 01/14/2023]
Abstract
Titanium and its alloys are characterized by high biocompatibility and good corrosion resistance as a result of the ability to form a TiO2 oxide layer. However, based on literature data it can be concluded that titanium degradation products, in the form of titanium particles, metal-protein groups, oxides and ions, may cause allergic, inflammatory reactions and bone resorption. The corrosion process of Ti6Al4V in the human body environment may be intensified by a decreased pH and concentration of chloride compounds. The purpose of this article was to analyze the corrosion resistance of the Ti6Al4V alloy, obtained by the selective laser melting method in a corrosion solution of neutral pH and in a solution simulating peri-implant inflammatory conditions. Additionally, the influence of zinc oxide deposited by the atomic layer deposition method on the improvement of the physicochemical behavior of the Ti6Al4V alloy was analyzed. In order to characterize the ZnO layer, tests of chemical and phase composition as well as surface morphology investigation were performed. As part of the assessment of the physicochemical properties of the uncoated samples and those with the ZnO layer, tests of wetting angle, pitting corrosion and impedance corrosion were carried out. The number of ions released after the potentiodynamic test were measured using the inductively coupled plasma atomic emission spectrometry (ICP-AES) method. It can be concluded that samples after surface modification (with the ZnO layer) were characterized by favorable physicochemical properties and had higher corrosion resistance.
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Affiliation(s)
- Anna Woźniak
- Department of Materials Engineering and Biomaterials, Faculty of Mechanical Engineering, Silesian University of Technology, Konarskiego 18A Street, 44-100 Gliwice, Poland; (B.Z.); (Z.B.); (M.A.)
- Correspondence: ; Tel.: +48-32-2372603
| | - Witold Walke
- Department of Biomaterials and Medical Devices Engineering, Faculty of Biomedical Engineering, Silesian University of Technology, Roosevelta 40 Street, 41-800 Zabrze, Poland;
| | - Agata Jakóbik-Kolon
- Department of Inorganic, Analytical Chemistry and Electrochemistry, Faculty of Chemistry, Silesian University of Technology, B. Krzywoustego 6 Street, 44-100 Gliwice, Poland;
| | - Bogusław Ziębowicz
- Department of Materials Engineering and Biomaterials, Faculty of Mechanical Engineering, Silesian University of Technology, Konarskiego 18A Street, 44-100 Gliwice, Poland; (B.Z.); (Z.B.); (M.A.)
| | - Zbigniew Brytan
- Department of Materials Engineering and Biomaterials, Faculty of Mechanical Engineering, Silesian University of Technology, Konarskiego 18A Street, 44-100 Gliwice, Poland; (B.Z.); (Z.B.); (M.A.)
| | - Marcin Adamiak
- Department of Materials Engineering and Biomaterials, Faculty of Mechanical Engineering, Silesian University of Technology, Konarskiego 18A Street, 44-100 Gliwice, Poland; (B.Z.); (Z.B.); (M.A.)
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19
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Morikawa K, Kazoe Y, Takagi Y, Tsuyama Y, Pihosh Y, Tsukahara T, Kitamori T. Advanced Top-Down Fabrication for a Fused Silica Nanofluidic Device. MICROMACHINES 2020; 11:E995. [PMID: 33182488 PMCID: PMC7697862 DOI: 10.3390/mi11110995] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 10/29/2020] [Accepted: 10/29/2020] [Indexed: 02/07/2023]
Abstract
Nanofluidics have recently attracted significant attention with regard to the development of new functionalities and applications, and producing new functional devices utilizing nanofluidics will require the fabrication of nanochannels. Fused silica nanofluidic devices fabricated by top-down methods are a promising approach to realizing this goal. Our group previously demonstrated the analysis of a living single cell using such a device, incorporating nanochannels having different sizes (102-103 nm) and with branched and confluent structures and surface patterning. However, fabrication of geometrically-controlled nanochannels on the 101 nm size scale by top-down methods on a fused silica substrate, and the fabrication of micro-nano interfaces on a single substrate, remain challenging. In the present study, the smallest-ever square nanochannels (with a size of 50 nm) were fabricated on fused silica substrates by optimizing the electron beam exposure time, and the absence of channel breaks was confirmed by streaming current measurements. In addition, micro-nano interfaces between 103 nm nanochannels and 101 μm microchannels were fabricated on a single substrate by controlling the hydrophobicity of the nanochannel surfaces. A micro-nano interface for a single cell analysis device, in which a nanochannel was connected to a 101 μm single cell chamber, was also fabricated. These new fabrication procedures are expected to advance the basic technologies employed in the field of nanofluidics.
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Affiliation(s)
- Kyojiro Morikawa
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan; (Y.K.); (Y.T.); (Y.P.)
| | - Yutaka Kazoe
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan; (Y.K.); (Y.T.); (Y.P.)
| | - Yuto Takagi
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan; (Y.K.); (Y.T.); (Y.P.)
| | - Yoshiyuki Tsuyama
- Department of Bioengineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan;
| | - Yuriy Pihosh
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan; (Y.K.); (Y.T.); (Y.P.)
| | - Takehiko Tsukahara
- Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1-N1-6, Ookayama, Meguro-ku, Tokyo 152-8550, Japan;
| | - Takehiko Kitamori
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan; (Y.K.); (Y.T.); (Y.P.)
- Department of Bioengineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan;
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20
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Ozcelik HG, Satiroglu E, Barisik M. Size dependent influence of contact line pinning on wetting of nano-textured/patterned silica surfaces. NANOSCALE 2020; 12:21376-21391. [PMID: 33078810 DOI: 10.1039/d0nr05392a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Wetting behavior on a heterogeneous surface undergoes contact angle hysteresis as the droplet stabilized at a metastable state with a contact angle significantly different from its equilibrium value due to contact line pinning. However, there is a lack of consensus on how to calculate the influence of pinning forces. In general, the pinning effect can be characterized as (i) microscopic behavior when a droplet is pinned and the contact angle increases/decreases as the droplet volume increases/decreases and (ii) macroscopic behavior as the pinning effects decrease and ultimately, disappear with the increase of the droplet size. The current work studied both behaviors using molecular dynamics (MD) simulation with more than 300 different size water droplets on silica surfaces with three different patterns across two different wetting conditions. Results showed that the contact angle increases linearly with increasing droplet volume through the microscopic behavior, while the droplet is pinned on top of a certain number of patterns. When we normalized the droplet size with the corresponding pattern size, we observed a "wetting similarity" that linear microscopic contact angle variations over different size heterogeneities continuously line up. This shows that the pinning force remains constant and the resulting pinning effects are scalable by the size ratio between the droplet and pattern, independent of the size-scale. The slope of these microscopic linear variations decreases with an increase in the droplet size as observed through the macroscopic behavior. We further found a universal behavior in the variation of the corresponding pinning forces, independent of the wetting condition. In macroscopic behavior, pinning effects become negligible and the contact angle reaches the equilibrium value of the corresponding surface when the diameter of the free-standing droplet is approximately equal to 24 times the size of the surface structure. We found that the pinning effect is scalable with the droplet volume, not the size of the droplet base.
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Affiliation(s)
- H Gokberk Ozcelik
- Department of Mechanical Engineering, Izmir Institute of Technology, Izmir, 35430, Turkey.
| | - Ezgi Satiroglu
- Department of Energy Systems Engineering, Izmir Institute of Technology, Izmir, 35430, Turkey
| | - Murat Barisik
- Department of Mechanical Engineering, Izmir Institute of Technology, Izmir, 35430, Turkey.
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21
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Kumar M, Bhardwaj R, Sahu KC. Wetting Dynamics of a Water Droplet on Micropillar Surfaces with Radially Varying Pitches. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:5312-5323. [PMID: 32356997 DOI: 10.1021/acs.langmuir.0c00697] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The wetting dynamics of a sessile droplet on square micropillar substrates with radially varying pitches, prepared on silicon wafers using a photolithography technique, is investigated experimentally. Two configurations are considered, namely, substrates with radially increasing pitch and radially decreasing pitch. The droplet initially placed at the center experiences a wettability gradient because of the variation in pitch of the micropillar substrate leading to complex wetting dynamics. We observed that the droplet remains in the Cassie-Baxter state in the case of a radially increasing pitch and exhibits a higher contact angle than that on a smooth surface during its spreading stage. In contrast, the droplet experiences the Wenzel condition in the case of a radially decreasing pitch and assumes a lower contact angle relative to that observed on a smooth surface. The wetted diameter of the droplet in the radially decreasing pitch configuration is found to be smaller than that observed in the radially increasing pitch configuration. Our study also reveals that increasing the size of the pillars increases the wetted diameter of the droplet in both configurations. Theoretical models developed using the Cassie-Baxter and Wenzel states for the radially increasing and radially decreasing pitches satisfactorily predict the experimental behaviors.
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Affiliation(s)
- Manish Kumar
- Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Rajneesh Bhardwaj
- Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Kirti Chandra Sahu
- Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Sangareddy 502 285, Telangana, India
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22
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Tao R, McHale G, Reboud J, Cooper JM, Torun H, Luo J, Luo J, Yang X, Zhou J, Canyelles-Pericas P, Wu Q, Fu Y. Hierarchical Nanotexturing Enables Acoustofluidics on Slippery yet Sticky, Flexible Surfaces. NANO LETTERS 2020; 20:3263-3270. [PMID: 32233442 PMCID: PMC7227016 DOI: 10.1021/acs.nanolett.0c00005] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The ability to actuate liquids remains a fundamental challenge in smart microsystems, such as those for soft robotics, where devices often need to conform to either natural or three-dimensional solid shapes, in various orientations. Here, we propose a hierarchical nanotexturing of piezoelectric films as active microfluidic actuators, exploiting a unique combination of both topographical and chemical properties on flexible surfaces, while also introducing design concepts of shear hydrophobicity and tensile hydrophilicity. In doing so, we create nanostructured surfaces that are, at the same time, both slippery (low in-plane pinning) and sticky (high normal-to-plane liquid adhesion). By enabling fluid transportation on such arbitrarily shaped surfaces, we demonstrate efficient fluid motions on inclined, vertical, inverted, or even flexible geometries in three dimensions. Such surfaces can also be deformed and then reformed into their original shapes, thereby paving the way for advanced microfluidic applications.
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Affiliation(s)
- Ran Tao
- Faculty
of Engineering and Environment, Northumbria
University, Newcastle
upon Tyne NE1 8ST, United
Kingdom
- Shenzhen
Key Laboratory of Advanced Thin Films and Applications, College of
Physics and Energy, Shenzhen University, 518060 Shenzhen, P. R. China
| | - Glen McHale
- Faculty
of Engineering and Environment, Northumbria
University, Newcastle
upon Tyne NE1 8ST, United
Kingdom
| | - Julien Reboud
- Division
of Biomedical Engineering, James Watt School of Engineering, University of Glasgow, Glasgow G12 8LT, United Kingdom
| | - Jonathan M. Cooper
- Division
of Biomedical Engineering, James Watt School of Engineering, University of Glasgow, Glasgow G12 8LT, United Kingdom
| | - Hamdi Torun
- Faculty
of Engineering and Environment, Northumbria
University, Newcastle
upon Tyne NE1 8ST, United
Kingdom
| | - JingTing Luo
- Shenzhen
Key Laboratory of Advanced Thin Films and Applications, College of
Physics and Energy, Shenzhen University, 518060 Shenzhen, P. R. China
| | - Jikui Luo
- College
of Information Science & Electronic Engineering, Zhejiang University, Hangzhou 310027, P. R. China
| | - Xin Yang
- Department
of Electrical and Electronic Engineering, School of Engineering, Cardiff University, Cardiff CF24 3AA, United Kingdom
| | - Jian Zhou
- College of
Mechanical and Vehicle Engineering, Hunan
University, Changsha 410082, P. R. China
| | - Pep Canyelles-Pericas
- Faculty
of Engineering and Environment, Northumbria
University, Newcastle
upon Tyne NE1 8ST, United
Kingdom
| | - Qiang Wu
- Faculty
of Engineering and Environment, Northumbria
University, Newcastle
upon Tyne NE1 8ST, United
Kingdom
| | - Yongqing Fu
- Faculty
of Engineering and Environment, Northumbria
University, Newcastle
upon Tyne NE1 8ST, United
Kingdom
- E-mail:
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23
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Yamagishi R, Maeda H, Kasuga T. Water wettability dependence on surface structure of a snail shell. BIOINSPIRATION & BIOMIMETICS 2020; 15:036001. [PMID: 32031998 DOI: 10.1088/1748-3190/ab7386] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
There are many reports on the special wettability of hierarchical surface structures in nature. Snail shells with three types of roughness of 10, 100, and 500 µm have a unique wetting behavior. In the present study, we investigate the influence of the surface structure on the water wettability using snail shells with different surface roughness. The wettability of a water droplet on the samples was evaluated. The three types of roughness on the surface structure of snail shell had higher water droplet spreading properties than the two types of roughness 500 µm and, 10 or 100 µm. Surface structures of snail shells with different surface roughness were simulated using epoxy resins to clarify the mechanism for the dynamics wetting behavior. The contact angle with a hydrophobic nature, of the epoxy resin with the three types of roughness decreased with increasing time, indicating a hydrophilic nature. The base diameter of the epoxy resins with the three types of roughness increased with increasing time. This was larger than that for a flat epoxy resin with hydrophilicity. Other epoxy resins with shell texture containing 100 and 500 or 10 and 500 µm roughness showed almost no change in the contact angle and diameter of the droplet base. The three types of roughness on the sample surface contributed to development of the water droplet spreading. The 10 µm roughness of the sample surface influenced the dynamic contact angles.
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Affiliation(s)
- Ryota Yamagishi
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
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24
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Griffiths SJ, Jantimapornkij P, Schmitz G. Miniaturization, Triple-Line Effects, and Reactive Wetting of Microsolder Interfaces. ACS APPLIED MATERIALS & INTERFACES 2020; 12:8935-8943. [PMID: 32027123 DOI: 10.1021/acsami.9b22512] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
While reactive microsolder joints are of ubiquitous importance in modern electronics, the effects of joint miniaturization on wetting behavior remain largely unexplored. We elucidate this fundamental question of scalability by investigating the wettability of eutectic SnPb solder on Cu and Ni-electrodeposited metallization strips of varying widths. Contact angles are presented in dependence of the metallization width which is varied from 3 mm down to ∼100 μm. The measured angles clearly increase with decreasing metallization width. Based on the measurements and by modifying Young's equation, it is shown that the behavior of the wetting angle can be quantitatively understood with an "effective" triple-line energy of ϵt = (753 ± 31) × 10-9J/m for SnPb on Cu. The interpretation of this energy term is discussed in relation to the forming intermetallic phase and the ensuing surface roughness. A remarkable similarity between the experimentally observed size dependence and the crossed-groove perturbation model of Huh and Mason demonstrates that the rough intermetallic phase induces wetting hysteresis such that it is quantitatively well described by an effective triple-line energy.
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Affiliation(s)
- Samuel J Griffiths
- Chair of Materials Physics, Institute for Materials Science , University of Stuttgart , Heisenbergstraße 3 , 70569 Stuttgart , Germany
| | - Patcharawee Jantimapornkij
- Chair of Materials Physics, Institute for Materials Science , University of Stuttgart , Heisenbergstraße 3 , 70569 Stuttgart , Germany
| | - Guido Schmitz
- Chair of Materials Physics, Institute for Materials Science , University of Stuttgart , Heisenbergstraße 3 , 70569 Stuttgart , Germany
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25
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Shardt N, Elliott JAW. Gibbsian Thermodynamics of Wenzel Wetting (Was Wenzel Wrong? Revisited). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:435-446. [PMID: 31869229 DOI: 10.1021/acs.langmuir.9b02984] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
When a drop is in contact with a rough surface, it can rest on top of the rough features (the Cassie-Baxter state) or it can completely fill the rough structure (the Wenzel state). The contact angle (θ) of a drop in these states is commonly predicted by the Cassie-Baxter or Wenzel equations, respectively, but the accuracy of these equations has been debated. Previously, we used fundamental Gibbsian composite-system thermodynamics to rigorously derive the Cassie-Baxter equation, and we found that the contact line determined the macroscopic contact angle, not the contact area that was originally proposed. Herein, to address the various perspectives on the Wenzel equation, we apply Gibbsian composite-system thermodynamics to derive the complete set of equilibrium conditions (thermal, chemical, and mechanical) for a liquid drop resting on a homogeneous rough solid substrate in the Wenzel mode of wetting. Through this derivation, we show that the roughness must be evaluated at the contact line, not over the whole interfacial area, and we propose a new Wenzel equation for a surface with pillars of equal height. We define a new dimensionless number H = h(1 - λsolid)/R to quantify when the drop's radius of curvature (R) is large enough compared to the size of the pillars for the new Wenzel equation to be simplified (h is the pillar height; λsolid is the line fraction of the spherical cap's circumference that is on the pillars). Our new line-roughness Wenzel equation can be simplified to cos θW = ρ cos θY when H ≪ 1, where ρ is the line roughness. We also perform a thermodynamic free-energy analysis to determine the stability of the equilibrium states that are predicted by our new Wenzel equation.
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Affiliation(s)
- Nadia Shardt
- Department of Chemical and Materials Engineering , University of Alberta , 9211-116 Street NW , T6G 1H9 Edmonton , Alberta , Canada
| | - Janet A W Elliott
- Department of Chemical and Materials Engineering , University of Alberta , 9211-116 Street NW , T6G 1H9 Edmonton , Alberta , Canada
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26
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Duan L, Ji X, Yang Y, Yang S, Lv X, Xie Y. Thickness-dependent fast wetting transitions due to the atomic layer deposition of zinc oxide on a micro-pillared surface. RSC Adv 2020; 10:1120-1126. [PMID: 35494465 PMCID: PMC9048290 DOI: 10.1039/c9ra08498c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 11/29/2019] [Indexed: 11/21/2022] Open
Abstract
Smart surfaces promote the fundamental understanding of wetting and are widely used in practical applications for energy and water collection. Light-induced switchable wettability facilitated by ZnO coatings, for instance, was developed for liquid manipulation at the surface. However, the transition of wetting states was reported to follow a hydrophobic–hydrophilic cycle in an hour, which is very long and may limit its future applications. We recently discovered that the cycle of the wetting state transitions on inorganic coatings can be shortened to less than 100 seconds by using ALD-coated ZnO on a pillared surface. However, the mechanisms are still unclear. Here, we investigated the effects of coating thickness on the transition speed and found that it significantly depended on the thickness of the coating with the optimal thickness less than 50 nm. We found that the minimum critical time for a wetting state transition cycle was less than 50 seconds with a thickness of 40 nm. Although the transition time of surfaces with coatings over 70 nm thickness remained constant at 10 min for a cycle, it was shorter than those of other deposition techniques for a coarse surface. Here, we propose a “penetration–diffusion” model to explain the fast and thickness-dependent wetting transitions. Our study may provide a new paradigm for fast wetting transition surfaces with cycle time within tens of seconds using a homogeneous thin layer coated on a rough surface. Smart surfaces promote the fundamental understanding of wetting and are widely used in practical applications for energy and water collection.![]()
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Affiliation(s)
- Libing Duan
- MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions
- School of Science
- Northwestern Polytechnical University
- Xi'an 710072
- China
| | - Xiangyang Ji
- MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions
- School of Science
- Northwestern Polytechnical University
- Xi'an 710072
- China
| | - Yajie Yang
- MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions
- School of Science
- Northwestern Polytechnical University
- Xi'an 710072
- China
| | - Sihang Yang
- MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions
- School of Science
- Northwestern Polytechnical University
- Xi'an 710072
- China
| | - Xinjun Lv
- MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions
- School of Science
- Northwestern Polytechnical University
- Xi'an 710072
- China
| | - Yanbo Xie
- MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions
- School of Science
- Northwestern Polytechnical University
- Xi'an 710072
- China
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27
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Peirce CAE, McBeath TM, Priest C, McLaughlin MJ. The Timing of Application and Inclusion of a Surfactant Are Important for Absorption and Translocation of Foliar Phosphoric Acid by Wheat Leaves. FRONTIERS IN PLANT SCIENCE 2019; 10:1532. [PMID: 31824546 PMCID: PMC6882945 DOI: 10.3389/fpls.2019.01532] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 11/01/2019] [Indexed: 05/26/2023]
Abstract
Introduction: Foliar applied phosphorus (P) has the potential to provide a more tactical approach to P fertilization that could enhance P use efficiency. The aims of this study were to investigate the influence of adjuvant choice and application timing of foliar applied phosphoric acid on leaf wettability, foliar uptake, translocation, and grain yield of wheat plants. Materials and Methods: We measured the contact angles of water and fertilizers on wheat leaves, and the uptake, translocation and wheat yield response to isotopically-labelled phosphoric acid in combination with five different adjuvants when foliar-applied to wheat at either early tillering or flag leaf emergence. Results: There was high foliar uptake of phosphoric acid in combination with all adjuvants that contained a surfactant, but only one treatment resulted in a 12% increase in grain yield and two treatments resulted in a decrease in grain yield. Despite the wettability of all foliar fertilizers being markedly different, foliar uptake was similar for all treatments that contained a surfactant. The translocation of phosphorus from foliar sources was higher when applied at a later growth stage than when applied at tillering despite the leaf surface properties that affect wettability being similar across all leaves at both growth stages. Discussion: Both the timing of foliar application and the inclusion of a surfactant in the formulation are important for absorption and translocation of phosphoric acid by wheat leaves, however high foliar uptake and translocation will not always translate to a yield increase.
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Affiliation(s)
- Courtney A. E. Peirce
- Soil Science, School of Agriculture, Food and Wine, The University of Adelaide, Glen Osmond, SA, Australia
| | - Therese M. McBeath
- Soil Science, School of Agriculture, Food and Wine, The University of Adelaide, Glen Osmond, SA, Australia
- CSIRO Agriculture and Food-Systems, Glen Osmond, SA, Australia
| | - Craig Priest
- Future Industries Institute, University of South Australia, Mawson Lakes, SA, Australia
| | - Michael J. McLaughlin
- Soil Science, School of Agriculture, Food and Wine, The University of Adelaide, Glen Osmond, SA, Australia
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Yan M, Zhang C, Sun G, Chen R, Liu Q, Liu J, Gao L, Yu J, Wang J. Self-Adjusting Lubricant-Infused Porous Hydrophobic Sticky Surfaces: Programmable Time Delay Switch for Smart Control of the Drop's Slide. ACS APPLIED MATERIALS & INTERFACES 2019; 11:43681-43688. [PMID: 31645098 DOI: 10.1021/acsami.9b14064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Although strategies for smart control of droplets by utilizing slippery surfaces that are typically made by infusing lubricants into porous surfaces are booming, no surface can smartly control the start or stop of droplet sliding without external environmental stimuli. A strategy for how surfaces alone, if constituted by lubricant-infused porous hydrophobic sticky surfaces (LIPHSS) with a specific interface self-adjusting system, can achieve the target of smart control of a drop's slide is presented here. The continuous self-adjustment of the interface formed by droplets and LIPHSS leads to the occurrence of droplet sinking behavior. The droplet's sinking reduces its sliding angle (SA) and thus can trigger the sliding of the droplet deposited on LIPHSS with a tilt base angle between the SA after sinking and the SA before sinking. Furthermore, regulating lubricant layer thickness and tilt base angle is an important way to achieve smart control of the time required to initiate the sliding of the droplet. The uniqueness of the study is focused on the clever extension of the sinking behavior of droplets on LIPHSS to achieve a programmable time delay switch to smart control the sliding of droplets.
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Affiliation(s)
- Minglong Yan
- Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education , Harbin Engineering University , Harbin 150001 , P. R. China
| | - Chunhong Zhang
- Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education , Harbin Engineering University , Harbin 150001 , P. R. China
| | - Gaohui Sun
- Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education , Harbin Engineering University , Harbin 150001 , P. R. China
| | - Rongrong Chen
- Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education , Harbin Engineering University , Harbin 150001 , P. R. China
| | - Qi Liu
- Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education , Harbin Engineering University , Harbin 150001 , P. R. China
| | - Jingyuan Liu
- Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education , Harbin Engineering University , Harbin 150001 , P. R. China
| | | | - Jing Yu
- Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education , Harbin Engineering University , Harbin 150001 , P. R. China
| | - Jun Wang
- Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education , Harbin Engineering University , Harbin 150001 , P. R. China
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29
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Basu S, Sarkar J. Selective adsorption of oil on self-organized surface patterns formed over soft thin PDMS films. Chem Eng Sci 2019. [DOI: 10.1016/j.ces.2019.07.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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30
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Wang Z, Lin K, Zhao YP. The effect of sharp solid edges on the droplet wettability. J Colloid Interface Sci 2019; 552:563-571. [DOI: 10.1016/j.jcis.2019.05.081] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 05/23/2019] [Accepted: 05/24/2019] [Indexed: 11/29/2022]
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31
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Mayama H, Nishino T, Sekiguchi A, Nishimura R, Uchida K, Yokojima S, Nakamura S, Nonomura Y. Theoretical Consideration of Wetting in Cassie-Baxter State on Multi-Pillar and Multi-Hole Surfaces: Thermodynamics and Laplace Pressure. J PHOTOPOLYM SCI TEC 2019. [DOI: 10.2494/photopolymer.32.279] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Tomoki Nishino
- Department of Mechanical Engineering, Ritumeikan University
| | - Atsushi Sekiguchi
- Department of Mechanical Engineering, Ritumeikan University
- Litho Tech Japan Corporation
| | - Ryo Nishimura
- Department of Materials Chemistry, Faculty of Science and Technology, Ryukoku University
| | - Kingo Uchida
- Department of Materials Chemistry, Faculty of Science and Technology, Ryukoku University
| | - Satoshi Yokojima
- Schoo of Pharmacy, Tokyo University of Pharmacy and Life Sciences
- RIKEN Science, Technology and Innovation Hub, Nakamura Laboratory
| | | | - Yoshinume Nonomura
- Department of Biochemical Engineering, Graduate School of Science and Engineering, Yamagata University
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32
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Zhang J, Huang H, Lu XY. Pinning-Depinning Mechanism of the Contact Line during Evaporation of Nanodroplets on Heated Heterogeneous Surfaces: A Molecular Dynamics Simulation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:6356-6366. [PMID: 31008602 DOI: 10.1021/acs.langmuir.9b00796] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Droplet evaporation on heterogeneous or patterned surfaces has numerous potential applications, for example, inkjet printing. The effect of surface heterogeneities on the evaporation of a nanometer-sized cylindrical droplet on a solid surface is studied using molecular dynamics simulations of Lennard-Jones particles. Different heterogeneities of the surface were achieved through alternating stripes of equal width but two chemical types, which lead to different contact angles. The evaporation induced by the heated substrate instead of the isothermal evaporation is investigated. It is found that the whole evaporation process is generally dominated by the nonuniform evaporation effect. However, at the initial moment, the volume expansion and local evaporation effects play important roles. From the nanoscale point of view, the slow movement of the contact line during the pinning process is observed, which is different from the macroscopic stationary pinning. Particularly, we found that the speed of the contact line may be not only affected by the intrinsic energy barrier between the two adjacent stripes ( ũ) but also relevant to the evaporation rate. Generally speaking, the larger the intrinsic energy barrier, the slower the movement of the contact line. At the specified temperature, when ũ is less than a critical energy barrier ( ũ*), the speed of the contact line would increase with the evaporate rate. When ũ > ũ*, the speed of the contact line is determined only by ũ and no longer affected by the evaporation rate at different stages (the first stick and the second stick).
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Affiliation(s)
- Jiajian Zhang
- Department of Modern Mechanics , University of Science and Technology of China , 96 JinZhai Road , Hefei 230026 , Anhui , China
| | - Haibo Huang
- Department of Modern Mechanics , University of Science and Technology of China , 96 JinZhai Road , Hefei 230026 , Anhui , China
| | - Xi-Yun Lu
- Department of Modern Mechanics , University of Science and Technology of China , 96 JinZhai Road , Hefei 230026 , Anhui , China
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33
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Cabezudo N, Sun J, Andi B, Ding F, Wang D, Chang W, Luo X, Xu BB. Enhancement of surface wettability via micro- and nanostructures by single point diamond turning. NANOTECHNOLOGY AND PRECISION ENGINEERING 2019. [DOI: 10.1016/j.npe.2019.03.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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34
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Telecka A, Mandsberg NK, Li T, Ludvigsen E, Ndoni S, Di Mundo R, Palumbo F, Fiutowski J, Chiriaev S, Taboryski R. Mapping the transition to superwetting state for nanotextured surfaces templated from block-copolymer self-assembly. NANOSCALE 2018; 10:20652-20663. [PMID: 30394480 DOI: 10.1039/c8nr07941b] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Adding roughness to hydrophilic surfaces is generally expected to enhance their wetting by water. Indeed, global free energy minimization predicts decreasing contact angles when roughness factor or surface energy increases. However, experimentally it is often found that water spreading on rough surfaces is impeded by pinning effects originating from local free energy minima; an effect, largely neglected in scientific literature. Here, we utilize Laplace pressure as a proxy for these local minima, and we map the transition to a superwetting state of hydrophilic nano-textured surfaces in terms of surface chemistry and texture geometry. We demonstrate the effect for polymer model surfaces templated from block-copolymer self-assembly comprising dense, nano-pillar arrays exhibiting strong pinning in their pristine state. By timed argon plasma exposure, we tune surface chemistry to map the transition into the superwetting state of low contact angle, which we show coincide with the surface supporting hemiwicking flow. For the near-ideal model surfaces, the transition to the superwetting state occurs below a critical material contact angle of ∼50°. We show that superwetting surfaces possess anti-fogging properties, and demonstrate long term stability of the superwetting effect by coating the nanotextured surfaces with ∼10 nm thin films of either tungsten or silica.
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Affiliation(s)
- Agnieszka Telecka
- Department of Micro- and Nanotechnology, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
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35
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Perween S, Khan Z, Singh S, Ranjan A. PVA-PDMS-Stearic acid composite nanofibrous mats with improved mechanical behavior for selective filtering applications. Sci Rep 2018; 8:16038. [PMID: 30375465 PMCID: PMC6207706 DOI: 10.1038/s41598-018-34440-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 10/12/2018] [Indexed: 02/07/2023] Open
Abstract
In this work, we report a facile way to fabricate composite nanofibrous mats of polyvinyl alcohol (PVA), polydimethylsiloxane (PDMS), and stearic acid (SA) by employing the electrospinning-technique, with PDMS fraction ranging from 40w% to nearly 80w%. The results show that for a predetermined fraction of PVA and SA, incorporation of an optimal amount of PDMS is necessary for which the mats exhibit the best mechanical behavior. Beyond this optimal PDMS fraction, the mechanical properties of the composite mats deteriorate. This result has been attributed to the ability of the SA molecules to mediate binding between the PVA and PDMS long-chain molecules via van-der-Waals bonding. The morphological, structural, mechanical, and thermal characterizations respectively using SEM, XRD, DMA/tensile test, and DSC lend support to this explanation. By this method, it is possible to control the hydrophilicity/oleophilicity of the mats, and the mats show an excellent selective permeability to oil as compared to water and successfully filter water from a water-in-oil emulsion. Incorporation of SA not only serves to aid in electrospinning of a PDMS-rich nanofibrous mat with good mechanical strength and control over hydrophilicity/oleophilicity, but also has a potential use in fabricating sheets impregnated with phase change materials for thermal energy storage.
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Affiliation(s)
- Shama Perween
- Rajiv Gandhi Institute of Petroleum Technology, Jais, Uttar Pradesh, India
| | - Ziyauddin Khan
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
- Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, SE-60174, Norrköping, Sweden
| | - Somendra Singh
- Rajiv Gandhi Institute of Petroleum Technology, Jais, Uttar Pradesh, India
| | - Amit Ranjan
- Rajiv Gandhi Institute of Petroleum Technology, Jais, Uttar Pradesh, India.
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36
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Yang Y, Zhang L, Wang J, Wang X, Duan L, Wang N, Xiao F, Xie Y, Zhao J. Inorganic Surface Coating with Fast Wetting-Dewetting Transitions for Liquid Manipulations. ACS APPLIED MATERIALS & INTERFACES 2018; 10:19182-19188. [PMID: 29767948 DOI: 10.1021/acsami.8b02537] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Liquid manipulation is a fundamental issue for microfluidics and miniaturized sensors. Fast wetting-state transitions by optical methods have proven being efficient for liquid manipulations by organic surface coatings, however rarely been achieved by using inorganic coatings. Here, we report a fast optical-induced wetting-state transition surface achieved by inorganic coating, enabling tens of second transitions for a wetting-dewetting cycle, shortened from an hour, as typically reported. Here, we demonstrate a gravity-driven microfluidic reactor and switch it to a mixer after a second-step exposure in a minimum of within 80 s of UV exposure. The fast wetting-dewetting transition surfaces enable the fast switchable or erasable smart surfaces for water collection, miniature chemical reaction, or sensing systems by using inorganic surface coatings.
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Affiliation(s)
| | | | - Jue Wang
- School of Advanced Materials, Shenzhen Graduate School , Peking University , Shenzhen 518055 , China
| | - Xinwei Wang
- School of Advanced Materials, Shenzhen Graduate School , Peking University , Shenzhen 518055 , China
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37
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Iliev S, Pesheva N, Iliev P. Contact angle hysteresis on doubly periodic smooth rough surfaces in Wenzel's regime: The role of the contact line depinning mechanism. Phys Rev E 2018; 97:042801. [PMID: 29758646 DOI: 10.1103/physreve.97.042801] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Indexed: 06/08/2023]
Abstract
We report here on the contact angle hysteresis, appearing when a liquid meniscus is in contact with doubly sinusoidal wavelike patterned surfaces in Wenzel's wetting regime. Using the full capillary model we obtain numerically the contact angle hysteresis as a function of the surface roughness factor and the equilibrium contact angle for a block case and a kink case contact line depinning mechanism. We find that the dependencies of the contact angle hysteresis on the surface roughness factor are different for the different contact line depinning mechanisms. These dependencies are different also for the two types of rough surfaces we studied. The relations between advancing, receding, and equilibrium contact angles are investigated. A comparison with the existing asymptotical, numerical, and experimental results is carried out.
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Affiliation(s)
- Stanimir Iliev
- Institute of Mechanics, Bulgarian Academy of Sciences, Acad. G. Bonchev St. 4, 1113 Sofia, Bulgaria
| | - Nina Pesheva
- Institute of Mechanics, Bulgarian Academy of Sciences, Acad. G. Bonchev St. 4, 1113 Sofia, Bulgaria
| | - Pavel Iliev
- Institute of Mechanics, Bulgarian Academy of Sciences, Acad. G. Bonchev St. 4, 1113 Sofia, Bulgaria
- ETH Zurich, Computational Physics for Engineering Materials, CH-8093 Zurich, Switzerland
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38
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Peng Y, Jin X, Zheng Y, Han D, Liu K, Jiang L. Direct Imaging of Superwetting Behavior on Solid-Liquid-Vapor Triphase Interfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29. [PMID: 28869679 DOI: 10.1002/adma.201703009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/17/2017] [Indexed: 05/11/2023]
Abstract
A solid-liquid-vapor interface dominated by a three-phase contact line usually serves as an active area for interfacial reactions and provides a vital clue to surface behavior. Recently, direct imaging of the triphase interface of superwetting interfaces on the microscale/nanoscale has attracted broad scientific attention for both theoretical research and practical applications, and has gradually become an efficient and intuitive approach to explore the wetting behaviors of various multiphase interfaces. Here, recent progress on characterizing the solid-liquid-vapor triphase interface on the microscale/nanoscale with diverse types of imaging apparatus is summarized. Moreover, the accurate, visible, and quantitative information that can be obtained shows the real interfacial morphology of the wetting behaviors of multiphase interfaces. On the basis of fundamental research, technical innovations in imaging and complicated multiphase interfaces of the superwetting surface are also briefly presented.
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Affiliation(s)
- Yun Peng
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing, 100191, P. R. China
| | - Xu Jin
- Research Institute of Petroleum, Exploration and Development, Petro China, Beijing, 100191, P. R. China
| | - Yongmei Zheng
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing, 100191, P. R. China
| | - Dong Han
- National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Kesong Liu
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing, 100191, P. R. China
| | - Lei Jiang
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing, 100191, P. R. China
- Laboratory of Bio-inspired Smart Interface Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
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39
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Oscurato SL, Borbone F, Maddalena P, Ambrosio A. Light-Driven Wettability Tailoring of Azopolymer Surfaces with Reconfigured Three-Dimensional Posts. ACS APPLIED MATERIALS & INTERFACES 2017; 9:30133-30142. [PMID: 28805057 DOI: 10.1021/acsami.7b08025] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The directional light-induced mass migration phenomenon arising in the photoresponsive azobenzene-containing materials has become an increasingly used approach for the fabrication of controlled tridimensional superficial textures. In the present work we demonstrate the tailoring of the superficial wettability of an azopolymer by means of the light-driven reconfiguration of an array of imprinted micropillars. Few simple illumination parameters are controlled to induce nontrivial wetting effects. Wetting anisotropy with controlled directionality, unidirectional spreading, and even polarization-intensity driven two-dimensional paths for wetting anisotropy are obtained starting from a single pristine pillar geometry. The obtained results prove that the versatility of the light-reconfiguration process, together with the possibility of reversible reshaping at reduced costs, represents a valid approach for both applications and fundamental studies in the field of geometry-based wettability of solid surfaces.
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Affiliation(s)
- Stefano Luigi Oscurato
- Dipartimento di Fisica E. Pancini, Università degli Studi di Napoli Federico II , Complesso Universitario di Monte Sant'Angelo, Via Cintia, 80126 Naples, Italy
| | - Fabio Borbone
- Dipartimento di Scienze Chimiche, Università degli Studi di Napoli Federico II , Complesso Universitario di Monte Sant'Angelo, Via Cintia, 80126 Naples, Italy
| | - Pasqualino Maddalena
- Dipartimento di Fisica E. Pancini, Università degli Studi di Napoli Federico II , Complesso Universitario di Monte Sant'Angelo, Via Cintia, 80126 Naples, Italy
| | - Antonio Ambrosio
- Center for Nanoscale Systems, Harvard University , 9 Oxford Street, Cambridge, Massachusetts 02138, United States
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40
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Singha SK, Das PK, Maiti B. Thermodynamic formulation of the barrier for heterogeneous pinned nucleation: Implication to the crossover scenarios associated with barrierless and homogeneous nucleation. J Chem Phys 2017. [PMID: 28641419 DOI: 10.1063/1.4985631] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The effect of contact line pinning on nucleation is reported using continuum thermodynamics. Based on the principle of the free-energy maximization, closed-form expressions in the dimensionless form for the free-energy of the three-phase metastable system and the thermodynamic barrier are formulated with respect to the system geometry and the substrate wettability. The condition of maximality limits the dynamic contact angle within the cluster-phase-phobic regime. The dimensionless nucleation barrier or the potency factor can be divided into two components related to the system geometry and the pinning effect. Depending on the relative value of the equilibrium and the critical dynamic contact angle, the contact line pinning can either have favorable or adverse effects. Associated pinning-depinning transition can also lead to the crossovers related to barrierless and homogeneous nucleation. Contact line tension is found to have a considerable effect during these transitional scenarios. Complete wetting transition associated with barrierless nucleation can take place due to the presence of tensile (negative) line tension. On the other hand, complete drying transition related to homogeneous nucleation can occur when line tension is compressive (positive) in nature. The pinning has a favorable effect only when the substrate wettability is within the cluster-phase-philic regime. There can be favorable, adverse, or no pinning effects when the substrate wettability is within the cluster-phase-phobic regime. Although the contact line is pinned, the minimum value of the potency factor is obtained when equilibrium and dynamic contact angles are equal.
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Affiliation(s)
- Sanat K Singha
- Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Prasanta K Das
- Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Biswajit Maiti
- Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
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41
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Zheng Y, Cheng J, Zhou C, Xing H, Wen X, Pi P, Xu S. Droplet Motion on a Shape Gradient Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:4172-4177. [PMID: 28398753 DOI: 10.1021/acs.langmuir.7b00227] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We demonstrate a facile method to induce water droplet motion on an wedge-shaped superhydrophobic copper surface combining with a poly(dimethylsiloxane) (PDMS) oil layer on it. The unbalanced interfacial tension from the shape gradient offers the actuating force. The superhydrophobicity critically eliminates the droplet contact line pinning and the slippery PDMS oil layer lubricates the droplet motion, which makes the droplet move easily. The maximum velocity and furthest position of droplet motion were recorded and found to be influenced by the gradient angle. The mechanism of droplet motion on the shape gradient surface is systematically discussed, and the theoretical model analysis is well matched with the experimental results.
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Affiliation(s)
- Yanfen Zheng
- School of Chemistry and Chemical Engineering, South China University of Technology , Guangzhou 510640, People's Republic of China
| | - Jiang Cheng
- School of Chemistry and Chemical Engineering, South China University of Technology , Guangzhou 510640, People's Republic of China
| | - Cailong Zhou
- School of Chemistry and Chemical Engineering, South China University of Technology , Guangzhou 510640, People's Republic of China
| | - Haiting Xing
- School of Chemistry and Chemical Engineering, South China University of Technology , Guangzhou 510640, People's Republic of China
| | - Xiufang Wen
- School of Chemistry and Chemical Engineering, South China University of Technology , Guangzhou 510640, People's Republic of China
| | - Pihui Pi
- School of Chemistry and Chemical Engineering, South China University of Technology , Guangzhou 510640, People's Republic of China
| | - Shouping Xu
- School of Chemistry and Chemical Engineering, South China University of Technology , Guangzhou 510640, People's Republic of China
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42
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Abstract
Superrepellency is an extreme situation where liquids stay at the tops of rough surfaces, in the so-called Cassie state. Owing to the dramatic reduction of solid/liquid contact, such states lead to many applications, such as antifouling, droplet manipulation, hydrodynamic slip, and self-cleaning. However, superrepellency is often destroyed by impalement transitions triggered by environmental disturbances whereas inverse transitions are not observed without energy input. Here we show through controlled experiments the existence of a "monostable" region in the phase space of surface chemistry and roughness, where transitions from Cassie to (impaled) Wenzel states become spontaneously reversible. We establish the condition for observing monostability, which might guide further design and engineering of robust superrepellent materials.
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Affiliation(s)
- Yanshen Li
- Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
- Center for Nano and Micro Mechanics, Tsinghua University, Beijing 100084, China
| | - David Quéré
- Physique et Mécanique des Milieux Hétérogènes, UMR 7636 du CNRS, École Supérieure de Physique et Chimie Industrielles, 75005 Paris, France
| | - Cunjing Lv
- Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
- Institute for Nano- and Microfluidics, Center of Smart Interfaces, Technische Universität Darmstadt, 64287 Darmstadt, Germany
| | - Quanshui Zheng
- Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China;
- Center for Nano and Micro Mechanics, Tsinghua University, Beijing 100084, China
- Applied Mechanics Lab, Tsinghua University, Beijing 100084, China
- State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China
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43
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Suzuki S, Ueno K. Apparent Contact Angle Calculated from a Water Repellent Model with Pinning Effect. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:138-143. [PMID: 28001421 DOI: 10.1021/acs.langmuir.6b03832] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A set of new theoretical equations for apparent contact angles is proposed. The equations are derived from an equilibrium of interfacial tensions of a three-phase contact line pinned at the edges of a fine structure. These equations are validated by comparison with contact-angle measurement results for 2 μL water droplets on poly(methyl methacrylate) microstructured samples with square pillars or holes. The equilibrium contact angles predicted by the new equations reasonably agree with the experimental results. In contrast, the values predicted by the Cassie-Baxter equation or the Wenzel equation do not qualitatively agree with the experimental results in pillar pattern cases because the Cassie-Baxter equation and the Wenzel equation do not account for the pinning effect.
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Affiliation(s)
- Shojiro Suzuki
- Graduate School of Engineering, Iwate University , 4-3-5 Ueda, Morioka 020-8551, Japan
| | - Kazuyuki Ueno
- Graduate School of Engineering, Iwate University , 4-3-5 Ueda, Morioka 020-8551, Japan
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44
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Contraires E, Teisseire J, Søndergård E, Barthel E. Wetting against the nap - how asperity inclination determines unidirectional spreading. SOFT MATTER 2016; 12:6067-6072. [PMID: 27373469 DOI: 10.1039/c6sm00523c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We have carried out wetting experiments on textured surfaces with high aspect ratio asperities in the Wenzel state. When inclination is imparted to the asperities, we observe a strictly unidirectional spreading opposite to the direction in which the asperities point. The advancing contact angle decreases markedly as inclination increases. A crude numerical analysis successfully accounts for this behaviour, highlighting the interplay between Gibbs pinning at the top of the structures and imbibition along the valleys between them. In Gibbs pinning non-linearities play a major role and we find that simple line averaging - i.e. a rule of mixture - cannot account for this evolution except for weak surface perturbations, i.e. large inclinations.
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Affiliation(s)
- Elise Contraires
- Laboratoire de Tribologie et Dynamique des Systèmes, UMR5513, CNRS, Ecole Centrale de Lyon, 36 avenue Guy de Collongue, FR-69134 Ecully cedex, France
| | - Jérémie Teisseire
- Surface du Verre et Interfaces, UMR 125 CNRS/Saint-Gobain Recherche, 39 quai Lucien Lefranc, 93303 Aubervilliers, France and PCRS, Saint-Gobain Recherche, 39 quai Lucien Lefranc, 93303 Aubervilliers, France
| | - Elin Søndergård
- Surface du Verre et Interfaces, UMR 125 CNRS/Saint-Gobain Recherche, 39 quai Lucien Lefranc, 93303 Aubervilliers, France
| | - Etienne Barthel
- École Supérieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI) ParisTech, PSL Research University, Sciences et Ingénierie de la matière Molle, CNRS UMR 7615, 10, Rue Vauquelin, F-75231 Paris Cedex 05, France and Sorbonne-Universités, UPMC Univ. Paris 06, SIMM, 10, Rue Vauquelin, F-75231 Paris Cedex 05, France
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Boulogne F, Ingremeau F, Limat L, Stone HA. Tuning the Receding Contact Angle on Hydrogels by Addition of Particles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:5573-5579. [PMID: 27185647 DOI: 10.1021/acs.langmuir.6b01209] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Control of the swelling, chemical functionalization, and adhesivity of hydrogels are finding new applications in a wide range of material systems. We investigate experimentally the effect of adsorbed particles on hydrogels on the depinning of contact lines. In our experiments, a water drop containing polystyrene microspheres is deposited on a swelling hydrogel, which leads to the drop absorption and particle deposition. Two regimes are observed: a decreasing drop height with a pinned contact line followed by a receding contact line. We show that increasing the particles concentration increases the duration of the first regime and significantly decreases the total absorption time. The adsorbed particles increase the pinning force at the contact line. Finally, we develop a method to measure the receding contact angle with the consideration of the hydrogel swelling.
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Affiliation(s)
- François Boulogne
- Department of Mechanical and Aerospace Engineering, Princeton University , Princeton, New Jersey 08544, United States
- Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057 CNRS, Université Paris Diderot , Bâtiment Condorcet, 10 rue Alice Domon et Léonie Duquet, Paris, France
| | - François Ingremeau
- Department of Mechanical and Aerospace Engineering, Princeton University , Princeton, New Jersey 08544, United States
- LIPhy, CNRS, and Université Grenoble Alpes, 140 Rue de la Physique, 38402 Saint-Martin-d'Hères, France
| | - Laurent Limat
- Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057 CNRS, Université Paris Diderot , Bâtiment Condorcet, 10 rue Alice Domon et Léonie Duquet, Paris, France
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University , Princeton, New Jersey 08544, United States
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Morikawa K, Tsukahara T. Fabrication of Hydrophobic Nanostructured Surfaces for Microfluidic Control. ANAL SCI 2016; 32:79-83. [PMID: 26753710 DOI: 10.2116/analsci.32.79] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In the field of micro- and nanofluidics, various kinds of novel devices have been developed. For such devices, not only fluidic control but also surface control of micro/nano channels is essential. Recently, fluidic control by hydrophobic nanostructured surfaces have attracted much attention. However, conventional fabrication methods of nanostructures require complicated steps, and integration of the nanostructures into micro/nano channels makes fabrication procedures even more difficult and complicated. In the present study, a simple and easy fabrication method of nanostructures integrated into microchannels was developed. Various sizes of nanostructures were successfully fabricated by changing the plasma etching time and etching with a basic solution. Furthermore, it proved possible to construct highly hydrophobic nanostructured surfaces that could effectively control the fluid in microchannels at designed pressures. We believe that the fabrication method developed here and the results obtained are valuable contributions towards further applications in the field of micro- and nanofluidics.
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Affiliation(s)
- Kyojiro Morikawa
- Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology
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Peirce CAE, Priest C, McBeath TM, McLaughlin MJ. Uptake of phosphorus from surfactant solutions by wheat leaves: spreading kinetics, wetted area, and drying time. SOFT MATTER 2016; 12:209-18. [PMID: 26457870 DOI: 10.1039/c5sm01380a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The delivery and uptake of nutrients at the surface of plant leaves is an important physicochemical phenomenon that depends on leaf surface morphology and chemistry, fertilizer formulation chemistry (including adjuvant and associated surfactants), wetting dynamics, and many other physical, chemical and biological factors. In this study, the role of spreading dynamics in determining uptake of the macronutrient phosphorus from phosphoric acid fertilizer solution in combination with three different adjuvants was measured in the absence of droplet run-off and splashing. When run-off and splashing losses were zero, spreading and drying rates had a small to negligible effect on the uptake efficiency. The results suggest that uptake may be much less sensitive to the specific choice of adjuvant and long time-scale spreading behaviour than one might intuitively expect.
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Affiliation(s)
- Courtney A E Peirce
- The University of Adelaide School of Agriculture, Food and Wine, Waite Campus, PB 1, Glen Osmond, SA 5064, Australia.
| | - Craig Priest
- Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA 5095, Australia
| | - Therese M McBeath
- The University of Adelaide School of Agriculture, Food and Wine, Waite Campus, PB 1, Glen Osmond, SA 5064, Australia. and CSIRO Agriculture Flagship, Waite Campus, PB 2, Glen Osmond, SA 5064, Australia
| | - Mike J McLaughlin
- The University of Adelaide School of Agriculture, Food and Wine, Waite Campus, PB 1, Glen Osmond, SA 5064, Australia. and CSIRO Agriculture Flagship, Waite Campus, PB 2, Glen Osmond, SA 5064, Australia
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Akerboom S, Kamperman M, Leermakers FAM. Three-gradient regular solution model for simple liquids wetting complex surface topologies. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2016; 7:1377-1396. [PMID: 27826512 PMCID: PMC5082679 DOI: 10.3762/bjnano.7.129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 08/25/2016] [Indexed: 05/12/2023]
Abstract
We use regular solution theory and implement a three-gradient model for a liquid/vapour system in contact with a complex surface topology to study the shape of a liquid drop in advancing and receding wetting scenarios. More specifically, we study droplets on an inverse opal: spherical cavities in a hexagonal pattern. In line with experimental data, we find that the surface may switch from hydrophilic (contact angle on a smooth surface θY < 90°) to hydrophobic (effective advancing contact angle θ > 90°). Both the Wenzel wetting state, that is cavities under the liquid are filled, as well as the Cassie-Baxter wetting state, that is air entrapment in the cavities under the liquid, were observed using our approach, without a discontinuity in the water front shape or in the water advancing contact angle θ. Therefore, air entrapment cannot be the main reason why the contact angle θ for an advancing water front varies. Rather, the contact line is pinned and curved due to the surface structures, inducing curvature perpendicular to the plane in which the contact angle θ is observed, and the contact line does not move in a continuous way, but via depinning transitions. The pinning is not limited to kinks in the surface with angles θkink smaller than the angle θY. Even for θkink > θY, contact line pinning is found. Therefore, the full 3D-structure of the inverse opal, rather than a simple parameter such as the wetting state or θkink, determines the final observed contact angle.
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Affiliation(s)
- Sabine Akerboom
- Physical Chemistry and Soft Matter, Wageningen University, Stippeneng 4, 6708 WE Wageningen, Netherlands
| | - Marleen Kamperman
- Physical Chemistry and Soft Matter, Wageningen University, Stippeneng 4, 6708 WE Wageningen, Netherlands
| | - Frans A M Leermakers
- Physical Chemistry and Soft Matter, Wageningen University, Stippeneng 4, 6708 WE Wageningen, Netherlands
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Gore P, Zachariah S, Gupta P, K. B. Multifunctional nano-engineered and bio-mimicking smart superhydrophobic reticulated ABS/fumed silica composite thin films with heat-sinking applications. RSC Adv 2016. [DOI: 10.1039/c6ra16781k] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
There are increasing requirements for engineered surfaces with distinct properties such as superhydrophobicity, self-cleaning, high thermal stability, and anti-corrosion.
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Affiliation(s)
- Prakash M. Gore
- Department of Materials Engineering
- Defence Institute of Advanced Technology (DU)
- Pune
- India
| | - Susan Zachariah
- Centre for Biopolymer Science and Technology, a unit of CIPET
- Cochin
- India
| | - Prashant Gupta
- Department of Ceramic Engineering
- Indian Institute of Technology (BHU)
- Varanasi-221005
- India
| | - Balasubramanian K.
- Department of Materials Engineering
- Defence Institute of Advanced Technology (DU)
- Pune
- India
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