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Kazaryan PS, Gallyamov MO, Kondratenko MS. Study of the Droplet Pinning Force in the Transition from Dry to Liquid-Infused Thin Polymer Films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:1114-1123. [PMID: 35015553 DOI: 10.1021/acs.langmuir.1c02767] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The change in the pinning force during the transition from dry to oil-impregnated thin polymer films is studied for droplets of water and hexadecane. A careful variation of the oil amount in the films is performed by means of supercritical impregnation. The film thickness dependence on the oil content is measured using ellipsometry and compared to gel swelling theory estimates. Depending on the oil content, two cases of pinning force behavior have been identified. For each case, the factors that determine the pinning force are discussed. The pinning force in the transition from dry to equilibrium swollen gel films is well approximated by the Joanny and de Gennes hysteresis model of dilute defects.
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Affiliation(s)
- Polina S Kazaryan
- Faculty of Physics, M. V. Lomonosov Moscow State University, Leninskie Gory 1-2, Moscow 119991, Russian Federation
| | - Marat O Gallyamov
- Faculty of Physics, M. V. Lomonosov Moscow State University, Leninskie Gory 1-2, Moscow 119991, Russian Federation
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova 28, Moscow 119991, Russian Federation
| | - Mikhail S Kondratenko
- Faculty of Physics, M. V. Lomonosov Moscow State University, Leninskie Gory 1-2, Moscow 119991, Russian Federation
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52
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Lee J, Lee MH, Choi CH. Design of Robust Lubricant-Infused Surfaces for Anti-Corrosion. ACS APPLIED MATERIALS & INTERFACES 2022; 14:2411-2423. [PMID: 34978419 DOI: 10.1021/acsami.1c22587] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
A lubricant-infused surface such as an oil-impregnated porous surface has great potentials for various applications due to its omniphobicity. However, the drainage and depletion of the lubricant liquid oil remain practical concerns for real applications. Here, we investigate the effect of a specially designed bottle-shaped nanopore of anodic aluminum oxide, which has a smaller pore diameter in the upper region than the lower one, on the oil retentivity and anti-corrosion efficacy. The effects of the viscosity and volatility of the lubricant oil were further investigated for synergy. Results show that the bottle-shaped pore helps to stably immobilize the lubricant oil in the nanostructure and significantly enhances the robustness and anti-corrosion efficacy, compared to the conventional cylindrical pores with straight walls as well as the hybrid one featured with additional pillar structures. Moreover, the enlarged oil capacity in the bottle-shaped pore allows the oil to cover the underlying metallic surface effectively at cracks, enhancing the damage tolerance with a unique self-healing capability. The oil with a higher viscosity further enhances the benefits so that the bottle-shaped pore impregnated with a higher-viscosity oil shows greater anti-corrosion efficacy. It suggests that the combination of the geometric features of nanopores and the fluid properties of lubricant liquid can lead to a maximized longevity and anti-corrosion efficacy of the liquid-infused surfaces for real applications.
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Affiliation(s)
- Junghoon Lee
- Department of Mechanical Engineering, Stevens Institute of Technology, Castle Point on Hudson, New Jersey 07030, United States
- Department of Metallurgical Engineering, Pukyong National University, Busan 48547, Republic of Korea
| | - Myeong-Hoon Lee
- Department of Marine Engineering, Korea Maritime and Ocean University, Busan 49112, Republic of Korea
| | - Chang-Hwan Choi
- Department of Mechanical Engineering, Stevens Institute of Technology, Castle Point on Hudson, New Jersey 07030, United States
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53
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Manipulation and control of droplets on surfaces in a homogeneous electric field. Nat Commun 2022; 13:289. [PMID: 35022399 PMCID: PMC8755840 DOI: 10.1038/s41467-021-27879-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 12/07/2021] [Indexed: 01/17/2023] Open
Abstract
A method to manipulate and control droplets on a surface is presented. The method is based on inducing electric dipoles inside the droplets using a homogeneous external electric field. It is shown that the repulsive dipole force efficiently suppresses the coalescence of droplets moving on a liquid-infused surface (LIS). Using a combination of experiments, numerical computations and semi-analytical models, the dependence of the repulsion force on the droplet volumes, the distance between the droplets and the electric field strength is revealed. The method allows to suppress coalescence in complex multi-droplet flows and is real-time adaptive. When the electric field strength exceeds a critical value, tip streaming from the droplets sets in. Based on that, it becomes possible to withdraw minute samples from an array of droplets in a parallel process. Control of droplet coalescence is a major challenge of droplet microfluidics. Here, the authors show that homogenous external electric field can induce dipoles inside droplets, which can be used to withdraw samples from an array of droplets.
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54
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Baumli P, Hauer L, Lorusso E, Aghili AS, Hegner KI, D'Acunzi M, Gutmann JS, Dünweg B, Vollmer D. Linear shrinkage of hydrogel coatings exposed to flow: interplay between dissolution of water and advective transport. SOFT MATTER 2022; 18:365-371. [PMID: 34889343 DOI: 10.1039/d1sm01297e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We investigate the shrinkage of a surface-grafted water-swollen hydrogel under shear flows of oils by laser scanning confocal microscopy. Interestingly, external shear flows of oil lead to linear dehydration and shrinkage of the hydrogel for all investigated flow conditions irrespective of the chemical nature of the hydrogel. The reason is that the finite solubility of water in oil removes water from the hydrogel continuously by diffusion. The flow advects the water-rich oil, as demonstrated by numerical solutions of the underlying convection-diffusion equation. In line with this hypothesis, shear does not cause gel shrinkage for water-saturated oils or non-solvents. The solubility of water in the oil will tune the dehydration dynamics.
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Affiliation(s)
- Philipp Baumli
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
| | - Lukas Hauer
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
| | - Emanuela Lorusso
- Deutsches Textilforschungszentrum Nord-West ÖP GmbH, Adlerstraße 1, 47798 Krefeld, Germany
| | | | - Katharina I Hegner
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
| | - Maria D'Acunzi
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
| | - Jochen S Gutmann
- Deutsches Textilforschungszentrum Nord-West ÖP GmbH, Adlerstraße 1, 47798 Krefeld, Germany
| | - Burkhard Dünweg
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
| | - Doris Vollmer
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
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55
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Lv F, Zhao F, Cheng D, Dong Z, Jia H, Xiao X, Orejon D. Bioinspired functional SLIPSs and wettability gradient surfaces and their synergistic cooperation and opportunities for enhanced condensate and fluid transport. Adv Colloid Interface Sci 2022; 299:102564. [PMID: 34861513 DOI: 10.1016/j.cis.2021.102564] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 11/15/2021] [Accepted: 11/15/2021] [Indexed: 01/16/2023]
Abstract
Bioinspired smart functional surfaces have received increasing attention in recent years owed to their tunable wettability and enhanced droplet transport suggesting them as excellent candidates for industrial and nanotechnology-related applications. More specifically, bioinspired slippery lubricant infused porous surfaces (SLIPSs) have been proposed for their low adhesion enabling continuous dropwise condensation (DWC) even of low-surface tension fluids. In addition, functional surfaces with chemical and/or structural wettability gradients have also been exploited empowering spontaneous droplet transport in a controlled manner. Current research has focused on the better understanding of the mechanisms and intimate interactions taking place between liquid droplets and functional surfaces or on the forces imposed by differences in surface wettability and/or by Laplace pressure owed to chemical or structural gradients. Nonetheless, less attention has been paid to the synergistic cooperation of efficiently driving droplet transport via chemical and/or structural patterns/gradients on a low surface energy/adhesion background imposed by SLIPSs, with the consequent promising potential for microfluidics and condensation heat transfer applications amongst others. This review provides a detailed and timely overview and summary on recent advances and developments on bioinspired SLIPSs and on wettability gradient surfaces with focus on their synergistic cooperation for condensation and fluid transport related applications. Firstly, the fundamental theory and mechanisms governing complex droplet transport on homogeneous, on wettability gradient surfaces and on inclined SLIPSs are introduced. Secondly, recent advances on the fabrication and characterization of SLIPSs and functional surfaces are presented. Then, the condensation performance on such functional surfaces comprising chemical or structural wettability gradients is reviewed and their applications on condensation heat transfer are summarized. Last a summary outlook highlighting the opportunities and challenges on the synergistic cooperation of SLIPSs and wettability gradient surfaces for heat transfer as well as future perspective in modern applications are presented.
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56
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Chen F, Wang Y, Tian Y, Zhang D, Song J, Crick CR, Carmalt CJ, Parkin IP, Lu Y. Robust and durable liquid-repellent surfaces. Chem Soc Rev 2022; 51:8476-8583. [DOI: 10.1039/d0cs01033b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
This review provides a comprehensive summary of characterization, design, fabrication, and application of robust and durable liquid-repellent surfaces.
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Affiliation(s)
- Faze Chen
- School of Mechanical Engineering, Tianjin University, Tianjin 300350, China
- Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education, Tianjin University, Tianjin 300350, China
| | - Yaquan Wang
- Department of Chemistry, School of Physical and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Yanling Tian
- School of Engineering, University of Warwick, Coventry CV4 7AL, UK
| | - Dawei Zhang
- School of Mechanical Engineering, Tianjin University, Tianjin 300350, China
- Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education, Tianjin University, Tianjin 300350, China
| | - Jinlong Song
- School of Mechanical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Colin R. Crick
- School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, UK
| | - Claire J. Carmalt
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK
| | - Ivan P. Parkin
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK
| | - Yao Lu
- Department of Chemistry, School of Physical and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
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57
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Li Y, Dekel DR, Manor O. Surface Acoustic Wave Mitigation of Precipitate Deposition on a Solid Surface─An Active Self-Cleaning Strategy. ACS APPLIED MATERIALS & INTERFACES 2021; 13:59471-59477. [PMID: 34851601 PMCID: PMC8678987 DOI: 10.1021/acsami.1c17778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 11/18/2021] [Indexed: 06/13/2023]
Abstract
We demonstrate the application of a 20 MHz frequency surface acoustic wave (SAW) in a solid substrate to render its surface "self-cleaning", redirecting the deposition of precipitating mass onto a nearby inert substrate. In our experiment, we confine a solution of poly(methyl methacrylate) polymer and a volatile toluene solvent between two substrates, lithium niobate and glass, at close proximity. We render the glass surface low energy by employing hydrophobic coating. In the absence of SAW excitation, we observe that the evaporation of the solvent yields polymer coating on the higher energy lithium niobate surface, while the glass surface is mostly devoid of polymer deposits. The application of a propagating SAW in the lithium niobate substrate mitigates the deposition of the polymer on its surface. As a response, we observe an increase in the deposition of the polymer precipitates on glass. Above a SAW power threshold, the polymer appears to deposit solely on glass, leaving the surface of the lithium niobate substrate devoid of polymer mass.
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Affiliation(s)
- Yifan Li
- The
Wolfson Faculty Department of Chemical Engineering, Technion—Israel Institute of Technology, Haifa 3200003, Israel
| | - Dario R. Dekel
- The
Wolfson Faculty Department of Chemical Engineering, Technion—Israel Institute of Technology, Haifa 3200003, Israel
- The
Nancy & Stephen Grand Technion Energy Program (GTEP), Technion Israel Institute of Technology, Haifa 3200003, Israel
| | - Ofer Manor
- The
Wolfson Faculty Department of Chemical Engineering, Technion—Israel Institute of Technology, Haifa 3200003, Israel
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58
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59
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Zhang J, Chen B, Chen X, Hou X. Liquid-Based Adaptive Structural Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2005664. [PMID: 33834566 DOI: 10.1002/adma.202005664] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 02/08/2021] [Indexed: 06/12/2023]
Abstract
Structural materials are used to provide stable mechanical architectures and transmit or support forces, and they play an important role in materials science and technology. During the long process of the exploitation of structural materials, the functionality of structural materials has gained prominence. Adaptive structures responding to external stimuli have come to the fore with significant advantages in structural materials. However, many solid adaptive structural materials still suffer from their single function and the lack of dynamic performance, such as issue around fouling and energy consumption, defects present everywhere in materials at the microscale, etc. To meet the increasing demands, more and more researchers have started turning their attention to liquid-based materials owing to their intrinsic spontaneous, dynamic, and functional properties. Liquid-based adaptive structural materials (LASMs) have been proposed and developed. Building upon both dynamic liquids and fixed solids, LASMs have been demonstrated to possess both dynamic adaptivity (from the active liquid part) and stable mechanical structure (from the fixed solid part), which are desired in many applications such as 3D printing, droplet manipulation, omniphobic surfaces, microfluidics, mass separation, etc. A unifying view of the recent progress of LASMs is presented, including liquid with particles, liquid with surfaces, as well as liquid with membranes. In addition, the discussion of the prospects and challenges are provided for promoting the development of LASMs.
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Affiliation(s)
- Jian Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Baiyi Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
- College of Materials, Xiamen University, Xiamen, 361005, China
| | - Xinyu Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Xu Hou
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
- College of Materials, Xiamen University, Xiamen, 361005, China
- Research Institute for Biomimetics and Soft Matter, Fujian Provincial Key Laboratory for Soft Functional Materials Research, Jiujiang Research Institute, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, China
- Tan Kah Kee Innovation Laboratory, Xiamen, Fujian, 361102, China
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60
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Henkel C, Snoeijer JH, Thiele U. Gradient-dynamics model for liquid drops on elastic substrates. SOFT MATTER 2021; 17:10359-10375. [PMID: 34747426 DOI: 10.1039/d1sm01032h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The wetting of soft elastic substrates exhibits many features that have no counterpart on rigid surfaces. Modelling the detailed elastocapillary interactions is challenging, and has so far been limited to single contact lines or single drops. Here we propose a reduced long-wave model that captures the main qualitative features of statics and dynamics of soft wetting, but which can be applied to ensembles of droplets. The model has the form of a gradient dynamics on an underlying free energy that reflects capillarity, wettability and compressional elasticity. With the model we first recover the double transition in the equilibrium contact angles that occurs when increasing substrate softness from ideally rigid towards very soft (i.e., liquid). Second, the spreading of single drops of partially and completely wetting liquids is considered showing that known dependencies of the dynamic contact angle on contact line velocity are well reproduced. Finally, we go beyond the single droplet picture and consider the coarsening for a two-drop system as well as for a large ensemble of drops. It is shown that the dominant coarsening mode changes with substrate softness in a nontrivial way.
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Affiliation(s)
- Christopher Henkel
- Institut für Theoretische Physik, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Str. 9, 48149 Münster, Germany.
| | - Jacco H Snoeijer
- Physics of Fluids Group and J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Uwe Thiele
- Institut für Theoretische Physik, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Str. 9, 48149 Münster, Germany.
- Center for Nonlinear Science (CeNoS), Westfälische Wilhelms-Universität Münster, Corrensstr. 2, 48149 Münster, Germany
- Center for Multiscale Theory and Computation (CMTC), Westfälische Wilhelms-Universität, Corrensstr. 40, 48149 Münster, Germany
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61
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Sun J, Jiang X, Weisensee PB. Enhanced Water Nucleation and Growth Based on Microdroplet Mobility on Lubricant-Infused Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:12790-12801. [PMID: 34699236 DOI: 10.1021/acs.langmuir.1c01559] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Lubricant-infused surfaces (LISs) can promote stable dropwise condensation and improve heat transfer rates due to a low nucleation free-energy barrier and high droplet mobility. Recent studies showed that oil menisci surrounding condensate microdroplets form distinct oil-rich and oil-poor regions. These topographical differences in the oil surface cause water microdroplets to rigorously self-propel long distances, continuously redistributing the oil film and potentially refreshing the surface for re-nucleation. However, the dynamic interplay between oil film redistribution, microdroplet self-propulsion, and droplet nucleation and growth is not yet understood. Using high-speed microscopy, we reveal that during water condensation on LISs, the smallest visible droplets (diameter: ∼1 μm, qualitatively representing nucleation) predominantly emerge in oil-poor regions due to a lower nucleation free-energy barrier. Considering the significant heat transfer performance of microdroplets (<10 μm) and transient characteristic of microdroplet movement, we compare the apparent nucleation rate density and water collection rate for LISs with oils of different viscosities and a solid hydrophobic surface at a wide range of subcooling temperatures. Generally, the lowest lubricant viscosity leads to the highest nucleation rate density. We characterize the length and frequency of microdroplet movement and attribute the nucleation enhancement primarily to higher droplet mobility and surface refreshing frequency. Interestingly and unexpectedly, hydrophobic surfaces outperform high-viscosity LISs at high subcooling temperatures but are generally inferior to any of the tested LISs at low temperature differences. To explain the observed nonlinearity between LISs and the solid hydrophobic surface, we introduce two dominant regimes that influence the condensation efficiency: mobility-limited and coalescence-limited. We compare these regimes based on droplet growth rates and water collection rates on the different surfaces. Our findings advance the understanding of dynamic water-lubricant interactions and provide new design rationales for choosing surfaces for enhanced dropwise condensation and water collection efficiencies.
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Affiliation(s)
- Jianxing Sun
- Department of Mechanical Engineering & Materials Science, Washington University in St. Louis, Saint Louis, Missouri 63130, United States
| | - Xinyu Jiang
- Department of Mechanical Engineering & Materials Science, Washington University in St. Louis, Saint Louis, Missouri 63130, United States
| | - Patricia B Weisensee
- Department of Mechanical Engineering & Materials Science, Washington University in St. Louis, Saint Louis, Missouri 63130, United States
- Institute of Materials Science and Engineering, Washington University in St. Louis, Saint Louis, Missouri 63130, United States
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62
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Semprebon C, Sadullah MS, McHale G, Kusumaatmaja H. Apparent contact angle of drops on liquid infused surfaces: geometric interpretation. SOFT MATTER 2021; 17:9553-9559. [PMID: 34730600 DOI: 10.1039/d1sm00704a] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We theoretically investigate the apparent contact angle of drops on liquid infused surfaces as a function of the relative size of the wetting ridge and the deposited drop. We provide an intuitive geometrical interpretation whereby the variation in the apparent contact angle is due to the rotation of the Neumann triangle at the lubricant-drop-gas contact line. We also derive linear and quadratic corrections to the apparent contact angle as power series expansion in terms of pressure differences between the lubricant, drop and gas phases. These expressions are much simpler and more compact compared to those previously derived by Semprebon et al. [Soft Matter, 2017, 13, 101-110].
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Affiliation(s)
- Ciro Semprebon
- Smart Materials and Surfaces Laboratory, Northumbria University, Newcastle upon Tyne NE1 8ST, UK.
| | - Muhammad Subkhi Sadullah
- King Abdullah University of Science and Technology (KAUST), Water Desalination and Reuse Center (WDRC), Biological and Environmental Science and Engineering (BESE) Division, Thuwal 23955-6900, Saudi Arabia
| | - Glen McHale
- School of Engineering, The University of Edinburgh, Kings Buildings, Edinburgh EH9 3FB, UK.
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63
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Numerical simulation of two-phase droplets on a curved surface using Surface Evolver. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.127418] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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64
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Coral-like silicone nanofilament coatings with extremely low ice adhesion. Sci Rep 2021; 11:20427. [PMID: 34650120 PMCID: PMC8516905 DOI: 10.1038/s41598-021-98215-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 08/02/2021] [Indexed: 11/09/2022] Open
Abstract
Passive icephobic surfaces can provide a cost and energy efficient solution to many icing problems that are currently handled with expensive active strategies. Water-repellent surface treatments are promising candidates for this goal, but commonly studied systems, such as superhydrophobic surfaces and Slippery Liquid Infused Porous Surfaces (SLIPS), still face challenges in the stability and durability of their properties in icing environments. In this work, environmental icing conditions are simulated using an Icing Wind Tunnel, and ice adhesion is evaluated with a Centrifugal Adhesion Test. We show that superhydrophobic coral-like Silicone Nanofilament (SNF) coatings exhibit extremely low ice adhesion, to the point of spontaneous ice detachment, and good durability against successive icing cycles. Moreover, SNFs-based SLIPS show stably low ice adhesion for the whole duration of the icing test. Stability of surface properties in a cold environment is further investigated with water wettability at sub-zero surface temperature, highlighting the effect of surface chemistry on superhydrophobicity under icing conditions.
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65
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Xu Y, Rather AM, Yao Y, Fang JC, Mamtani RS, Bennett RKA, Atta RG, Adera S, Tkalec U, Wang X. Liquid crystal-based open surface microfluidics manipulate liquid mobility and chemical composition on demand. SCIENCE ADVANCES 2021; 7:eabi7607. [PMID: 34597134 PMCID: PMC10938512 DOI: 10.1126/sciadv.abi7607] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 08/10/2021] [Indexed: 05/22/2023]
Abstract
The ability to control both the mobility and chemical compositions of microliter-scale aqueous droplets is an essential prerequisite for next-generation open surface microfluidics. Independently manipulating the chemical compositions of aqueous droplets without altering their mobility, however, remains challenging. In this work, we address this challenge by designing a class of open surface microfluidic platforms based on thermotropic liquid crystals (LCs). We demonstrate, both experimentally and theoretically, that the unique positional and orientational order of LC molecules intrinsically decouple cargo release functionality from droplet mobility via selective phase transitions. Furthermore, we build sodium sulfide–loaded LC surfaces that can efficiently precipitate heavy metal ions in sliding water droplets to final concentration less than 1 part per million for more than 500 cycles without causing droplets to become pinned. Overall, our results reveal that LC surfaces offer unique possibilities for the design of novel open surface fluidic systems with orthogonal functionalities.
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Affiliation(s)
- Yang Xu
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Adil M. Rather
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Yuxing Yao
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Jen-Chun Fang
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Rajdeep S. Mamtani
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Robert K. A. Bennett
- Department of Electrical and Computer Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Richard G. Atta
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Solomon Adera
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Uroš Tkalec
- Institute of Biophysics, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia
- Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška 160, 2000 Maribor, Slovenia
- Department of Condensed Matter Physics, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - Xiaoguang Wang
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA
- Sustainability Institute, The Ohio State University, Columbus, OH 43210, USA
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66
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Tang Z, Lin S, Wang ZL. Quantifying Contact-Electrification Induced Charge Transfer on a Liquid Droplet after Contacting with a Liquid or Solid. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2102886. [PMID: 34476851 DOI: 10.1002/adma.202102886] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 07/13/2021] [Indexed: 06/13/2023]
Abstract
Contact electrification (CE) is a common physical phenomenon, and its mechanisms for solid-solid and liquid-solid cases have been widely discussed. However, the studies about liquid-liquid CE are hindered by the lack of proper techniques. Here, a contactless method is proposed for quantifying the charges on a liquid droplet based on the combination of electric field and acoustic field. The liquid droplet is suspended in an acoustic field, and an electric field force is created on the droplet to balance the acoustic trap force. The amount of charges on the droplet is thus calculated based on the equilibrium of forces. Further, the liquid-solid and liquid-liquid CE are both studied by using the method, and the latter is focused. The behavior of negatively precharged liquid droplet in the liquid-liquid CE is found to be different from that of the positively precharged one. The results show that the silicone oil droplet prefers to receive negative charges from a negatively charged aqueous droplet rather than positive charges from a positively charged aqueous droplet, which provides a strong evidence about the dominant role played by electron transfer in the liquid-liquid CE.
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Affiliation(s)
- Zhen Tang
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, 100083, P. R. China
- School of Nanoscience and Technology, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Shiquan Lin
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, 100083, P. R. China
- School of Nanoscience and Technology, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Zhong Lin Wang
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, 100083, P. R. China
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332-0245, USA
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67
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Fabrication and durability characterization of superhydrophobic and lubricant-infused surfaces. J Colloid Interface Sci 2021; 608:662-672. [PMID: 34628325 DOI: 10.1016/j.jcis.2021.09.099] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 09/17/2021] [Accepted: 09/18/2021] [Indexed: 01/12/2023]
Abstract
HYPOTHESIS Practical applications of non-wetting surfaces require good mechanical durability in the wet environments for which they are intended to be used. Durability of non-wetting surfaces is influenced by the surface features, interaction with the functionalization agent, and the lubricant properties that can be tuned independently to identify optimal combination. EXPERIMENTS In this study, superhydrophobic and lubricant-infused surfaces are fabricated on copper tubes using chemical etching and electrodeposition texturing techniques, six different functionalizing agents, and five different infused lubricants. Through 180 fabrication combinations and 102 durability tests, each parameter is systematically studied for contributions to initial non-wetting behavior and its durability in heated, wet environment, under high-energy water jet impingement, and under accelerated flow conditions. FINDINGS Among the adsorbing and curing functionalization agents investigated, n-Hexadecyl mercaptan that belongs to the sulfhydryl group and Sylgard-184, respectively, showed high durability in heated water immersion and under jet impingement tests. For lubricant-infused surfaces, lubricants with high surface tension demonstrated high durability in heated water immersion test, whereas durability in hydrodynamic conditions is closely correlated to lubricant viscosity. Results showed that a lubricant-infused surface will maintain its non-wetting properties in dropwise condensation conditions for approximately 1.5 years.
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68
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Bhatt B, Gupta S, Sharma M, Khare K. Dewetting of non-polar thin lubricating films underneath polar liquid drops on slippery surfaces. J Colloid Interface Sci 2021; 607:530-537. [PMID: 34509731 DOI: 10.1016/j.jcis.2021.08.211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 08/30/2021] [Accepted: 08/31/2021] [Indexed: 11/28/2022]
Abstract
HYPOTHESIS The stability of thin lubricating fluid-coated slippery surfaces depends on the surface energy of the underlying solid surface. High energy solid surfaces coated with thin lubricating oil lead to the dewetting of the oil films upon depositing aqueous drops on them. Hence such surfaces are very suitable to investigate dewetting of thick films (thickness > 500 nm), which otherwise is not possible using a conventional dewetting system. EXPERIMENTS Lubricating films of different thicknesses are coated on hydrophilic solid surfaces, and glycerol drops are deposited on them. Fluorescence imaging of lubricating films and macroscopic wetting behavior of glycerol drops are analyzed to understand the dewetting phenomenon. FINDINGS Underneath lubricating films undergo initial thinning and subsequently dewet. The dewetting dynamics during hole nucleation and growth and the final pattern of the dewetted oil droplets depend strongly on the thickness of the lubricating films. Ultrathin films dewet spontaneously via homogeneous nucleation, whereas thicker films dewet via heterogeneous nucleation. During dewetting, the apparent contact angle and radius of glycerol drops follow universal scaling behavior.
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Affiliation(s)
- Bidisha Bhatt
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India
| | - Shivam Gupta
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India
| | - Meenaxi Sharma
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India
| | - Krishnacharya Khare
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India.
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69
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Zheng SF, Gross U, Wang XD. Dropwise condensation: From fundamentals of wetting, nucleation, and droplet mobility to performance improvement by advanced functional surfaces. Adv Colloid Interface Sci 2021; 295:102503. [PMID: 34411880 DOI: 10.1016/j.cis.2021.102503] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 08/02/2021] [Accepted: 08/03/2021] [Indexed: 01/22/2023]
Abstract
As a ubiquitous vapor-liquid phase-change process, dropwise condensation has attracted tremendous research attention owing to its remarkable efficiency of energy transfer and transformative industrial potential. In recent years, advanced functional surfaces, profiting from great progress in modifying micro/nanoscale features and surface chemistry on surfaces, have led to exciting advances in both heat transfer enhancement and fundamental understanding of dropwise condensation. In this review, we discuss the development of some key components for achieving performance improvement of dropwise condensation, including surface wettability, nucleation, droplet mobility, and growth, and discuss how they can be elaborately controlled as desired using surface design. We also present an overview of dropwise condensation heat transfer enhancement on advanced functional surfaces along with the underlying mechanisms, such as jumping condensation on nanostructured superhydrophobic surfaces, and new condensation characteristics (e.g., Laplace pressure-driven droplet motion, hierarchical condensation, and sucking flow condensation) on hierarchically structured surfaces. Finally, the durability, cost, and scalability of specific functional surfaces are focused on for future industrial applications. The existing challenges, alternative strategies, as well as future perspectives, are essential in the fundamental and applied aspects for the practical implementation of dropwise condensation.
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70
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Zhang P, Liu Y, Liao C, Luo H, Jing G. Drops Sliding on Non-SLIPS Structures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:9053-9058. [PMID: 34269063 DOI: 10.1021/acs.langmuir.1c01063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Inspired by a plant leaf, a slippery liquid-infused porous surface (SLIPS) exhibits attractive nonwetting and self-cleaning abilities. However, rigorous requirements for the infused liquid layer and its inevitable loss limit its practical use. Here, we propose a model structure defined as a non-SLIPS by introducing solid nanostructures covered with a discontinuous lubricant film. This non-SLIPS tuned by solid wettability achieves the excellent self-cleaning feature with a small sliding angle comparable to the counterpart of a typical SLIPS. This sliding angle α* can be further reduced to a saturated plateau by a slight enhancement of hydrophobicity of the solid nanostructures. Interestingly, the sliding velocity remains almost constant for all of these non-SLIPS samples at a given tilt angle, independent of solid wettability. We formulate the slippery mechanism by defining an energy barrier responsible for the sliding initiation on the non-SLIPS. This energy barrier of the non-SLIPS is correlated, with a qualitative agreement, to the molecular adsorption on the solid nanostructures. The antibiological contamination is confirmed for this non-SLIPS, indicating its excellent self-cleaning ability. The findings suggest that the new surfaces, even with the gradual depletion of the infused oil layer, exhibit the nondegradation of the self-cleaning performance.
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Affiliation(s)
- Peixin Zhang
- School of Physics, State Key Laboratory of Photon-Technology in Western China Energy, Northwest University, Xi'an 710127, China
| | - Yanan Liu
- School of Physics, State Key Laboratory of Photon-Technology in Western China Energy, Northwest University, Xi'an 710127, China
| | - Chunyan Liao
- School of Physics, State Key Laboratory of Photon-Technology in Western China Energy, Northwest University, Xi'an 710127, China
| | - Hao Luo
- School of Physics, State Key Laboratory of Photon-Technology in Western China Energy, Northwest University, Xi'an 710127, China
| | - Guangyin Jing
- School of Physics, State Key Laboratory of Photon-Technology in Western China Energy, Northwest University, Xi'an 710127, China
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71
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Li J, Li W, Tang X, Han X, Wang L. Lubricant-Mediated Strong Droplet Adhesion on Lubricant-Impregnated Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:8607-8615. [PMID: 34213350 DOI: 10.1021/acs.langmuir.1c01245] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Lubricant-impregnated surfaces have recently emerged as a new type of multifunctional coating with a promising capability in exhibiting low friction or contact angle hysteresis. However, lubricant-infused surfaces severely suffer from the tensile droplet-lubricant adhesion. In this study, we show that lubricant-infused surfaces allow for a strong tensile droplet adhesion, which results in the generation of an offspring residual droplet when a droplet detaches from the surface. Such tensile liquid-liquid adhesion and the corresponding liquid residue are solely mediated by the lubricant, independent of the underlying surface topography. We reveal how the lubricant film mediates droplet adhesion by measuring the maximum adhesion force and liquid residue and theoretically analyzing Laplace pressure force from the droplet shape and surface tension force depending on the contact line. Further, the presence of lubricant-induced adhesion considerably compromises the advantages of lubricant-infused surfaces in some applications. The lubricant-triggered tensile adhesion hampers the loss-free droplet transfer away from the surfaces in the photoelectrically and magnetically driven droplet manipulation. In addition, we demonstrate that the lubricant-triggered adhesion plays a dominant role in attenuating the efficiency of fog harvesting by impeding the shedding of the intercepted droplets by comparing the onset time, droplet radius, and collection efficiency. These findings advance our fundamental understanding of droplet adhesion on lubricant-infused surfaces and significantly benefit the design of lubricant-infused surfaces for various applications.
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Affiliation(s)
- Jiaqian Li
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, 999077, China
| | - Wei Li
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, 999077, China
| | - Xin Tang
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, 999077, China
| | - Xing Han
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, 999077, China
| | - Liqiu Wang
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, 999077, China
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72
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Gunjan MR, Kumar A, Raj R. Cloaked Droplets on Lubricant-Infused Surfaces: Union of Constant Mean Curvature Interfaces Dictated by Thin-Film Tension. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:6601-6612. [PMID: 34028279 DOI: 10.1021/acs.langmuir.0c03560] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
It has been recently shown that small-volume droplets on lubricant-infused surfaces (LISs) can be analytically modeled using rotationally symmetric constant mean curvature (CMC) surfaces. While such an approach is available for noncloaked droplets, a similar approach is missing for cloaked droplets that are ubiquitous in a number of LIS-related applications. The presence of a thin cloaking film on the top spherical cap portion and its gradual transition to a bulk meniscus remain unaddressed for its implications on the interfacial profile of cloaked droplets. Here, we take into account the cloaking film tension and the disjoining pressure to present a mean curvature-based framework for modeling cloaked droplets on LISs. The transition of the bulk meniscus to a thin film is formulated as a transition regime, which is then modeled as a single imaginary point akin to the Neumann point of noncloaked droplets. We next show that the shape of a small droplet on a LIS essentially obeys a simple fundamental mean curvature relation that changes forms depending on the regimes of lubrication and whether the droplet is cloaked or noncloaked. We validate our framework with the droplet profiles recorded during the evaporation of cloaked droplets in our experiments, as well as those published in the literature. In addition, we also demonstrate the ability to model the shapes of floating droplets on LISs reported in the literature. In addition to quantifying the effect of disjoining pressure on interfacial profiles, we importantly unmask the behavior of the contact line, which is optically covered by the lubricant meniscus around the droplets on LISs.
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Affiliation(s)
- Madhu Ranjan Gunjan
- Thermal and Fluid Transport Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Patna, R113, Block III, Bihta, Bihar 801103, India
| | - Alok Kumar
- Thermal and Fluid Transport Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Patna, R113, Block III, Bihta, Bihar 801103, India
| | - Rishi Raj
- Thermal and Fluid Transport Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Patna, R113, Block III, Bihta, Bihar 801103, India
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73
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Sett S, Oh J, Cha H, Veriotti T, Bruno A, Yan X, Barac G, Bolton LW, Miljkovic N. Lubricant-Infused Surfaces for Low-Surface-Tension Fluids: The Extent of Lubricant Miscibility. ACS APPLIED MATERIALS & INTERFACES 2021; 13:23121-23133. [PMID: 33949848 DOI: 10.1021/acsami.1c02716] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Lubricant-infused surfaces (LISs) and slippery liquid-infused porous surfaces (SLIPSs) have shown remarkable success in repelling low-surface-tension fluids. The atomically smooth, defect-free slippery surface leads to reduced droplet pinning and omniphobicity. However, the presence of a lubricant introduces liquid-liquid interactions with the working fluid. The commonly utilized lubricants for LISs and SLIPSs, although immiscible with water, show various degrees of miscibility with organic polar and nonpolar working fluids. Here, we rigorously investigate the extent of miscibility by considering a wide range of liquid-vapor surface tensions (12-73 mN/m) and different categories of lubricants having a range of viscosities (5-2700 cSt). Using high-fidelity analytical chemistry techniques including X-ray photoelectron spectroscopy, nuclear magnetic resonance, thermogravimetric analysis, and two-dimensional gas chromatography, we quantify lubricant miscibility to parts per billion accuracy. Furthermore, we quantify lubricant concentrations in the collected condensate obtained from prolonged condensation experiments with ethanol and hexane to delineate mixing and shear-based lubricant drainage mechanisms and to predict the lifetime of LISs and SLIPSs. Our work not only elucidates the effect of lubricant properties on miscibility with various fluids but also develops guidelines for developing stable and robust LISs and SLIPSs.
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Affiliation(s)
- Soumyadip Sett
- Department of Mechanical Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States
| | - Junho Oh
- Department of Mechanical Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States
| | - Hyeongyun Cha
- Department of Mechanical Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States
| | - Tincuta Veriotti
- BP Corporation North America, Inc., 150 West Warrenville Road, Naperville, Illinois 60563, United States
| | - Alessandra Bruno
- BP Corporation North America, Inc., 150 West Warrenville Road, Naperville, Illinois 60563, United States
| | - Xiao Yan
- Department of Mechanical Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States
| | - George Barac
- BP Corporation North America, Inc., 150 West Warrenville Road, Naperville, Illinois 60563, United States
| | - Leslie W Bolton
- BP plc, Chertsey Road, Sunbury-on-Thames, Middlesex TW16 7LN, U.K
| | - Nenad Miljkovic
- Department of Mechanical Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States
- Department of Electrical and Computer Engineering, University of Illinois, Urbana, Illinois 61801, United States
- Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, United States
- International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
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74
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Stoddard R, Nithyanandam K, Pitchumani R. Steam condensation heat transfer on lubricant-infused surfaces. iScience 2021; 24:102336. [PMID: 33889827 PMCID: PMC8050781 DOI: 10.1016/j.isci.2021.102336] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/07/2021] [Accepted: 03/16/2021] [Indexed: 12/02/2022] Open
Abstract
Steam condensation is fundamental to several industrial processes, including power generation, desalination, and water harvesting. Lubricant-infused surfaces (LISs) promote sustained dropwise condensation, leading to significantly higher heat transfer performance that trades off with durability. Here, we present a systematic study on lubricant-infused copper tubes in a partial vacuum environment typical of power plant condensers to elucidate the influence of the design parameters—texturing, functionalizing agent, and lubricant viscosity—on condensation heat transfer performance and durability. Heat transfer effectiveness is introduced as a relevant parameter to quantify the effects of condensation heat transfer coefficient enhancement on the overall system heat transfer performance. Analytical expressions are developed for lubricant retention fraction and heat transfer effectiveness in terms of Bond number, viscosity ratio, and a dimensionless logarithmic mean temperature difference that can be used for predicting the performance of a LIS or for designing surfaces for a desired performance. Presents condensation heat transfer enhancement using liquid infused surfaces Studies conducted in a typical power plant condenser environment Results quantified using heat transfer effectiveness for a system perspective Analytical relationships derived for LIS heat transfer effectiveness and durability
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Affiliation(s)
- Ryan Stoddard
- Advanced Materials and Technologies Laboratory, Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA 24061-0238, USA
| | - Karthik Nithyanandam
- Advanced Materials and Technologies Laboratory, Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA 24061-0238, USA
| | - Ranga Pitchumani
- Advanced Materials and Technologies Laboratory, Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA 24061-0238, USA
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75
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Kim J, Hwang H, Butt HJ, Wooh S. Designing the shape of supraparticles by controlling the apparent contact angle and contact line friction of droplets. J Colloid Interface Sci 2021; 588:157-163. [PMID: 33388581 DOI: 10.1016/j.jcis.2020.12.072] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 12/16/2020] [Accepted: 12/20/2020] [Indexed: 10/22/2022]
Abstract
Surface-templated evaporation-driven supraparticle synthesis is a versatile method for supraparticle fabrication. A supraparticle is formed by drying droplet of a colloidal dispersion on liquid repellent surfaces, allowing precise control of the size and mean composition of the supraparticles. The crucial factor determining the morphology is the motion of the contact line of the dispersion droplet on the liquid repellent surface. Here, we study effects of (i) the apparent contact angle and (ii) the contact line friction of a droplet on the shape of the supraparticle. In order to change the initial apparent contact angle of the dispersion droplet a surfactant was added to decrease surface tension. In addition, two different liquid repellent surfaces were used: a polydimethysiloxane (PDMS) grafted surface and a lubricated surface. Both surfaces exhibited distinctly different contact line friction during evaporation. As the initial contact angle of a droplet decreases and friction of a contact line increases, flatter supraparticles are fabricated. By using this simple manipulation principle, eventually, various shapes of supraparticles can be obtained, such as mushroom, hemispherical, convex lens, and disk shapes. This study presents fundamental and critical information that allow us to manipulate the shape of a supraparticle via surface-templated evaporation-driven synthesis that increases the scalability of supraparticles for use in a wide range of applications.
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Affiliation(s)
- Jihye Kim
- School of Chemical Engineering & Materials Science, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul 06974, Republic of Korea
| | - Hyesun Hwang
- School of Chemical Engineering & Materials Science, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul 06974, Republic of Korea
| | - Hans-Jürgen Butt
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Sanghyuk Wooh
- School of Chemical Engineering & Materials Science, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul 06974, Republic of Korea.
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76
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Hauer L, Wong WSY, Donadei V, Hegner KI, Kondic L, Vollmer D. How Frost Forms and Grows on Lubricated Micro- and Nanostructured Surfaces. ACS NANO 2021; 15:4658-4668. [PMID: 33647197 PMCID: PMC7992192 DOI: 10.1021/acsnano.0c09152] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 02/23/2021] [Indexed: 06/12/2023]
Abstract
Frost is ubiquitously observed in nature whenever warmer and more humid air encounters colder than melting point surfaces (e.g., morning dew frosting). However, frost formation is problematic as it damages infrastructure, roads, crops, and the efficient operation of industrial equipment (i.e., heat exchangers, cooling fins). While lubricant-infused surfaces offer promising antifrosting properties, underlying mechanisms of frost formation and its consequential effect on frost-to-surface dynamics remain elusive. Here, we monitor the dynamics of condensation frosting on micro- and hierarchically structured surfaces (the latter combines micro- with nano- features) infused with lubricant, temporally and spatially resolved using laser scanning confocal microscopy. The growth dynamics of water droplets differs for micro- and hierarchically structured surfaces, by hindered drop coalescence on the hierarchical ones. However, the growth and propagation of frost dendrites follow the same scaling on both surface types. Frost propagation is accompanied by a reorganization of the lubricant thin film. We numerically quantify the experimentally observed flow profile using an asymptotic long-wave model. Our results reveal that lubricant reorganization is governed by two distinct driving mechanisms, namely: (1) frost propagation speed and (2) frost dendrite morphology. These in-depth insights into the coupling between lubricant flow and frost formation/propagation enable an improved control over frosting by adjusting the design and features of the surface.
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Affiliation(s)
- Lukas Hauer
- Physics
at Interfaces, Max Planck Institute for
Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - William S. Y. Wong
- Physics
at Interfaces, Max Planck Institute for
Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Valentina Donadei
- Faculty
of Engineering and Natural Sciences, Tampere
University, P.O. Box 589, FI-33014 Tampere, Finland
| | - Katharina I. Hegner
- Physics
at Interfaces, Max Planck Institute for
Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Lou Kondic
- Department
of Mathematical Sciences and Center for Applied Mathematics and Statistics, New Jersey Institute of Technology, Newark, New Jersey 07102, United States
| | - Doris Vollmer
- Physics
at Interfaces, Max Planck Institute for
Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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77
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Bender DN, Zhang K, Wang J, Liu G. Hard yet Flexible Transparent Omniphobic GPOSS Coatings Modified with Perfluorinated Agents. ACS APPLIED MATERIALS & INTERFACES 2021; 13:10467-10479. [PMID: 33596043 DOI: 10.1021/acsami.0c23151] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Transparent materials with glasslike hardness and polymer-like flexibility are highly useful but rare. This paper reports the incorporation of the low-surface-tension pentafluoropropionic acid (FC2-COOH) or tridecafluoroheptanoic acid (FC6-COOH) into a 3-glycidyloxypropyl polyhedral oligomeric silsesquioxane (GPOSS) coating to yield hard/flexible omniphobic coatings. To avoid the macrophase separation of these additives from GPOSS and thus maintain the coating's high transparency, they are first reacted with excess GPOSS via the opening of the glycidyl rings with the carboxy groups to produce mixtures of GPOSS and GPOSS-FC2 or GPOSS-FC6. The fluorinated GPOSS mixtures are then photochemically cured. This study investigates the influence of the type and amount of a fluorinated agent used on the wetting and mechanical properties of the coatings. The wetting properties studied include surface energies, liquid sliding behavior, and repellency against an artificial fingerprint liquid. Meanwhile, the mechanical properties include pencil hardness, Young's modulus, hardness, and resistance to abrasion by steel wool and cheesecloth. Aside from producing coatings that may serve as a viable alternative for the currently used hard/flexible coatings in foldable smartphones, this paper provides guidelines for producing coatings with further improved omniphobicity and wear resistance.
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Affiliation(s)
- Desiree N Bender
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, Canada K7L 3N6
| | - Kaka Zhang
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, Canada K7L 3N6
| | - Jiandong Wang
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, Canada K7L 3N6
| | - Guojun Liu
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, Canada K7L 3N6
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78
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Kim J, Shim W, Jo SM, Wooh S. Evaporation driven synthesis of supraparticles on liquid repellent surfaces. J IND ENG CHEM 2021. [DOI: 10.1016/j.jiec.2020.12.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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79
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Xie L, Cui X, Liu J, Lu Q, Huang J, Mao X, Yang D, Tan J, Zhang H, Zeng H. Nanomechanical Insights into Versatile Polydopamine Wet Adhesive Interacting with Liquid-Infused and Solid Slippery Surfaces. ACS APPLIED MATERIALS & INTERFACES 2021; 13:6941-6950. [PMID: 33523622 DOI: 10.1021/acsami.0c22073] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Mussel-inspired polydopamine (PDA) can be readily deposited on almost all kinds of substrates and possesses versatile wet adhesion. Meanwhile, slippery surfaces have attracted much attention for their self-cleaning capabilities. It remains unclear how the versatile PDA adhesive would interact with slippery surfaces. In this work, both liquid-infused poly(tetrafluoroethylene) (PTFE) (LI-PTFE) and solid slippery surfaces (i.e., self-assembly of small thiol-terminated organosilane, polysiloxane covalently attached to substrates) were fabricated to investigate their capability to prevent PDA deposition. It was found that PDA particles could be easily deposited on a PTFE membrane and the two types of solid slippery surfaces, which resulted in the alternation of their surface wettability and slippery behavior of water droplets. Adhesion was detected between a PDA-coated silica colloidal probe and the PTFE membrane or solid slippery surfaces through quantitative force measurements using an atomic force microscope (AFM), mainly due to van der Waals (vdW) and hydrophobic interactions, which led to the PDA deposition phenomenon. In contrast, LI-PTFE with a thin liquid lubricant film could effectively prevent PDA deposition, with negligible changes in surface morphology, wettability, and slippery characteristics. Although PDA particles could be loosely attached to the lubricant/water interface for LI-PTFE based on the capillary adhesion measured by AFM, they could be readily removed by gentle rinsing with water, as demonstrated by the ultralow friction over LI-PTFE as compared to PTFE using lateral force microscopy (LFM). Our results indicate that LI-PTFE possesses excellent antifouling and self-cleaning properties even when interacting with the versatile PDA wet adhesives. This work provides new insights into the deposition of PDA on slippery surfaces and their interaction mechanism at the nanoscale, with useful implications for the design and development of novel slippery surfaces.
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Affiliation(s)
- Lei Xie
- School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Xin Cui
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Jing Liu
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Qiuyi Lu
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Jun Huang
- Center for Advanced Jet Engineering Technologies (CaJET), Key Laboratory of High Efficiency and Clean Mechanical Manufacture (Ministry of Education), School of Mechanical Engineering, Shandong University, Jinan 250061, China
| | - Xiaohui Mao
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Diling Yang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Jinglin Tan
- School of Chemical and Environmental Engineering, Jiujiang University, Jiujiang 332005, China
| | - Hao Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Hongbo Zeng
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
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80
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Hu X, Wang Z, Hwang DJ, Colosqui CE, Cubaud T. Viscous liquid-liquid wetting and dewetting of textured surfaces. SOFT MATTER 2021; 17:879-886. [PMID: 33237108 DOI: 10.1039/d0sm01524e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We experimentally investigate the spreading and receding behavior of small water droplets immersed in viscous oils on grid-patterned surfaces using synchronized bottom and profile views. In particular, the evolution of apparent advancing and receding contact angles of droplets fed at constant flow rate is studied as a function of grid surface coverage and height for a wide range of external phase viscosity. Detailed examination of droplet aspect ratio during inflation process provides an averaging method for characterization of quasi-static advancing angles on heterogeneous surfaces. Droplets spreading in partial Cassie state on planar microfluidic grids are also shown to capture oil patches that further evolve into trapped oil droplets depending on grid aspect ratio. The natural retraction velocity of thin water films is examined based on external phase velocity and regime maps of trapped droplets are delineated based on control parameters.
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Affiliation(s)
- Xiaoyi Hu
- Department of Mechanical Engineering, Stony Brook University, Stony Brook, NY 11794, USA.
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81
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Choi JW, Ham D, Han S, Noh DY, Kang HC. Nanoscale Soft Wetting Observed in Co/Sapphire during Pulsed Laser Irradiation. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:268. [PMID: 33498510 PMCID: PMC7909543 DOI: 10.3390/nano11020268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 01/19/2021] [Accepted: 01/19/2021] [Indexed: 11/24/2022]
Abstract
Liquid drops on deformable soft substrates exhibit quite complicated wetting behavior as compared to those on rigid solid substrates. We report on a soft wetting behavior of Co nanoparticles (NPs) on a sapphire substrate during pulsed laser-induced dewetting (PLID). Co NPs produced by PLID wetted the sapphire substrate with a contact angle near 70°, which is in contrast to typical dewetting behavior of metal thin films exhibiting contact angles greater than 90°. In addition, a nanoscale γ-Al2O3 wetting ridge about 15 nm in size and a thin amorphous Al2O3 interlayer were observed around and beneath the Co NP, respectively. The observed soft wetting behavior strongly indicates that the sapphire substrate became soft and deformable during PLID. Moreover, the soft wetting was augmented under PLID in air due to the formation of a CoO shell, resulting in a smaller contact angle near 30°.
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Affiliation(s)
- Jung Won Choi
- School of Materials Science and Engineering and Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Korea; (J.W.C.); (S.H.)
| | - Daseul Ham
- Department of Materials Science and Engineering, Chosun University, Gwangju 61452, Korea;
| | - Seonghyun Han
- School of Materials Science and Engineering and Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Korea; (J.W.C.); (S.H.)
| | - Do Young Noh
- School of Materials Science and Engineering and Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Korea; (J.W.C.); (S.H.)
| | - Hyon Chol Kang
- Department of Materials Science and Engineering, Chosun University, Gwangju 61452, Korea;
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82
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Holweger HJ, Jamali M, Tafreshi HV. Centrifugal Detachment of Compound Droplets from Fibers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:928-938. [PMID: 33398995 DOI: 10.1021/acs.langmuir.0c03317] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
This article presents the first experimental-computational study on the centrifugal detachment of a compound droplet (e.g., a primary water droplet cloaked by an immiscible oil) from a fiber. The work was intended to establish a method for quantifying the force needed to detach compound droplets of different compositions from a fiber. More importantly, our study was aimed at improving the understanding of the interplay between interfacial and external forces acting on a compound droplet during forceful detachment. The experiments were conducted using DI water, for the primary droplet, and silicone or mineral oil, for the cloaking fluid. It was observed from the experiments that the silicone-oil-cloaked droplets behave differently from the mineral-oil-cloaked droplets. It was also observed that detachment force decreases with increasing the oil-to-water volume ratio. The simulations were performed using the Surface Evolver (SE) finite element code programmed for the complicated four-phase (air, water, oil, and solid) interfacial problem at hand. Our simulations revealed the evolution of the interfacial forces between the interacting phases under an increasing external body force on the droplet. The simulations also allowed us to define effective interfacial tensions and contact angles for detaching compound droplets, for the first time. Reasonable agreement was observed between the experimental measurements and computational results.
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Affiliation(s)
- H J Holweger
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia 23284-3015, United States
| | - M Jamali
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina 27695-7910, United States
| | - H Vahedi Tafreshi
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina 27695-7910, United States
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83
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Shek ACM, Semprebon C, Panter JR, Kusumaatmaja H. Capillary Bridges on Liquid-Infused Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:908-917. [PMID: 33395301 DOI: 10.1021/acs.langmuir.0c03220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We numerically study two-component capillary bridges formed when a liquid droplet is placed in between two liquid-infused surfaces (LIS). In contrast to commonly studied one-component capillary bridges on noninfused solid surfaces, two-component liquid bridges can exhibit a range of different morphologies where the liquid droplet is directly in contact with two, one, or none of the LIS substrates. In addition, the capillary bridges may lose stability when compressed due to the envelopment of the droplet by the lubricant. We also characterize the capillary force, maximum separation, and effective spring force and find that they are influenced by the shape and size of the lubricant ridge. Importantly, these can be tuned to increase the effective capillary adhesion strength by manipulating the lubricant pressure, Neumann angle, and wetting contact angles. As such, LIS are not only "slippery" parallel to the surface, but they are also "sticky" perpendicular to the surface.
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Affiliation(s)
- Alvin C M Shek
- Department of Physics, Durham University, Durham DH1 3LE, U.K
| | - Ciro Semprebon
- Department of Mathematics, Physics and Electrical Engineering, Northumbria University, Newcastle upon Tyne NE1 8ST, U.K
| | - Jack R Panter
- Department of Physics, Durham University, Durham DH1 3LE, U.K
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84
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Baumli P, D'Acunzi M, Hegner KI, Naga A, Wong WSY, Butt HJ, Vollmer D. The challenge of lubricant-replenishment on lubricant-impregnated surfaces. Adv Colloid Interface Sci 2021; 287:102329. [PMID: 33302056 DOI: 10.1016/j.cis.2020.102329] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 11/22/2020] [Accepted: 11/23/2020] [Indexed: 11/18/2022]
Abstract
Lubricant-impregnated surfaces are two-component surface coatings. One component, a fluid called the lubricant, is stabilized at a surface by the second component, the scaffold. The scaffold can either be a rough solid or a polymeric network. Drops immiscible with the lubricant, hardly pin on these surfaces. Lubricant-impregnated surfaces have been proposed as candidates for various applications, such as self-cleaning, anti-fouling, and anti-icing. The proposed applications rely on the presence of enough lubricant within the scaffold. Therefore, the quality and functionality of a surface coating are, to a large degree, given by the extent to which it prevents lubricant-depletion. This review summarizes the current findings on lubricant-depletion, lubricant-replenishment, and the resulting understanding of both processes. A multitude of different mechanisms can cause the depletion of lubricant. Lubricant can be taken along by single drops or be sheared off by liquid flowing across. Nano-interstices and scaffolds showing good chemical compatibility with the lubricant can greatly delay lubricant depletion. Often, depletion of lubricant cannot be avoided under dynamic conditions, which warrants lubricant-replenishment strategies. The strategies to replenish lubricant are presented and range from spraying or stimuli-responsive release to built-in reservoirs.
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Affiliation(s)
- Philipp Baumli
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Maria D'Acunzi
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Katharina I Hegner
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Abhinav Naga
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - William S Y Wong
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Hans-Jürgen Butt
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Doris Vollmer
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
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85
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Evaporation mediated translation and encapsulation of an aqueous droplet atop a viscoelastic liquid film. J Colloid Interface Sci 2021; 581:334-349. [DOI: 10.1016/j.jcis.2020.07.123] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/22/2020] [Accepted: 07/23/2020] [Indexed: 11/23/2022]
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86
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Majhy B, Jain SK, Sen AK. Attraction and Repulsion between Liquid Droplets over a Liquid-Impregnated Surface. J Phys Chem Lett 2020; 11:10001-10006. [PMID: 33179937 DOI: 10.1021/acs.jpclett.0c02997] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We show that adjacent liquid droplets exhibit long-range attraction and repulsion on an immiscible liquid impregnating a surface when either the drop or the impregnating liquid is volatile. Remarkably, we find that at small times the interaction is attractive, analogous to the "Cheerios effect", but at large times the interaction becomes repulsive depicting the "reverse-Cheerios effect". Our study reveals that the interaction is underpinned by wetting and capillarity, buoyancy, and evaporation phenomena. We experimentally observe the interaction between a pair of droplets and provide a theoretical framework to quantitatively predict their transport behavior.
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Affiliation(s)
- B Majhy
- Micro Nano Bio-Fluidics Unit, Fluid Systems Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, Tamilnadu, India
| | - S K Jain
- Micro Nano Bio-Fluidics Unit, Fluid Systems Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, Tamilnadu, India
| | - A K Sen
- Micro Nano Bio-Fluidics Unit, Fluid Systems Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, Tamilnadu, India
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87
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Wang C, Guo Z. A comparison between superhydrophobic surfaces (SHS) and slippery liquid-infused porous surfaces (SLIPS) in application. NANOSCALE 2020; 12:22398-22424. [PMID: 33174577 DOI: 10.1039/d0nr06009g] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Slippery liquid-infused porous surfaces inspired by the Nepenthes pitcher plant exhibit excellent performances and are known for their extremely low contact angle hysteresis (<5°) and smooth surface. In contrast, superhydrophobic surfaces (SHS) exhibit poor pressure stability, difficulty in self-healing, and difficulty in removing low surface tension liquids or organic solvents, which can affect the stable air layer. Thus, these issues can be avoided through the replacement of SHS with slippery liquid infused porous surfaces (SLIPS). In this review, the theoretical models of SHS and SLIPS are classified initially, and several design standards for the preparation of SLIPS are briefly described. Then, we focus on comparing the differences in the application of SHS and SLIPS, such as pressure stability, transparency, and droplet manipulation. However, there are still some problems that need to be improved during the preparation of SLIPS, such as the evaporation of the lubricant layer, the use of a lubricant layer of toxic perfluoropolyether and other substances, and easily lost nanostructured lubricant layer. Accordingly, several new improved methods are proposed in this review, and finally, the potential applications and development prospects of SLIPS are presented.
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Affiliation(s)
- Chenghong Wang
- Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei University, Wuhan 430062, P. R. China.
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88
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Tang G, Niu D, Guo L, Xu J. Failure and Recovery of Droplet Nucleation and Growth on Damaged Nanostructures: A Molecular Dynamics Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:13716-13724. [PMID: 33147034 DOI: 10.1021/acs.langmuir.0c02809] [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
The condensate flooding during dropwise condensation causes serious deterioration in heat transfer performance. In this study, the three-dimensional large-scale molecular dynamics simulation is carried out to investigate the droplet state transition from local flooding mode to Wenzel or from Wenzel to Cassie due to the droplet coalescence under the effect of nanostructure size. In particular, the effect of nanostructure breakage on droplet nucleation and growth is discussed to reveal the mechanism of dropwise condensation heat transfer deterioration. As a potential solution, the lubricant-impregnated surface is proposed to recover the preferred Cassie state by regulating the dynamic wetting characteristics of droplets, and thus the detrimental effect of nanostructure breakage could be effectively avoided.
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Affiliation(s)
- Guihua Tang
- MOE Key Laboratory of Thermo-Fluid Science and Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Dong Niu
- MOE Key Laboratory of Thermo-Fluid Science and Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Lin Guo
- MOE Key Laboratory of Thermo-Fluid Science and Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Jinliang Xu
- Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization, North China Electric Power University, Beijing 102206, China
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89
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Cao Y, Jana S, Tan X, Bowen L, Zhu Y, Dawson J, Han R, Exton J, Liu H, McHale G, Jakubovics NS, Chen J. Antiwetting and Antifouling Performances of Different Lubricant-Infused Slippery Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:13396-13407. [PMID: 33141589 DOI: 10.1021/acs.langmuir.0c00411] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The concept of slippery lubricant-infused surfaces has shown promising potential in antifouling for controlling detrimental biofilm growth. In this study, nontoxic silicone oil was either impregnated into porous surface nanostructures, referred to as liquid-infused surfaces (LIS), or diffused into a polydimethylsiloxane (PDMS) matrix, referred to as a swollen PDMS (S-PDMS), making two kinds of slippery surfaces. The slippery lubricant layers have extremely low contact angle hysteresis, and both slippery surfaces showed superior antiwetting performances with droplets bouncing off or rolling transiently after impacting the surfaces. We further demonstrated that water droplets can remove dust from the slippery surfaces, thus showing a "cleaning effect". Moreover, "coffee-ring" effects were inhibited on these slippery surfaces after droplet evaporation, and deposits could be easily removed. The clinically biofilm-forming species P. aeruginosa (as a model system) was used to further evaluate the antifouling potential of the slippery surfaces. The dried biofilm stains could still be easily removed from the slippery surfaces. Additionally, both slippery surfaces prevented around 90% of bacterial biofilm growth after 6 days compared to the unmodified control PDMS surfaces. This investigation also extended across another clinical pathogen, S. epidermidis, and showed similar results. The antiwetting and antifouling analysis in this study will facilitate the development of more efficient slippery platforms for controlling biofouling.
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Affiliation(s)
- Yunyi Cao
- School of Engineering, Newcastle University, Newcastle Upon Tyne NE1 7RU, United Kingdom
| | - Saikat Jana
- School of Engineering, Newcastle University, Newcastle Upon Tyne NE1 7RU, United Kingdom
| | - Xiaolong Tan
- School of Pharmacy, Newcastle University, Newcastle Upon Tyne NE1 7RU, United Kingdom
| | - Leon Bowen
- Department of Physics, Durham University, Durham DH1 3LE, United Kingdom
| | - Yufeng Zhu
- School of Engineering, Newcastle University, Newcastle Upon Tyne NE1 7RU, United Kingdom
| | - Jack Dawson
- School of Engineering, Newcastle University, Newcastle Upon Tyne NE1 7RU, United Kingdom
| | - Rui Han
- School of Engineering, Newcastle University, Newcastle Upon Tyne NE1 7RU, United Kingdom
| | - John Exton
- School of Engineering, Newcastle University, Newcastle Upon Tyne NE1 7RU, United Kingdom
| | - Hongzhong Liu
- School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710054, P. R. China
| | - Glen McHale
- Smart Materials and Surfaces Laboratory, Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne NE1 8ST, United Kingdom
- School of Engineering, University of Edinburgh, Edinburgh EH9 3FB, United Kingdom
| | - Nicholas S Jakubovics
- School of Dental Sciences, Newcastle University, Newcastle Upon Tyne NE2 4BW, United Kingdom
| | - Jinju Chen
- School of Engineering, Newcastle University, Newcastle Upon Tyne NE1 7RU, United Kingdom
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90
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Sadullah MS, Panter JR, Kusumaatmaja H. Factors controlling the pinning force of liquid droplets on liquid infused surfaces. SOFT MATTER 2020; 16:8114-8121. [PMID: 32734997 DOI: 10.1039/d0sm00766h] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Liquid infused surfaces with partially wetting lubricants have recently been exploited for numerous intriguing applications, such as for droplet manipulation, droplet collection and spontaneous motion. When partially wetting lubricants are used, the pinning force is a key factor that can strongly affect droplet mobility. Here, we derive an analytical prediction for contact angle hysteresis in the limit where the meniscus size is much smaller than the droplet, and numerically study how it is controlled by the solid fraction, the lubricant wetting angles, and the various fluid surface tensions. We further relate the contact angle hysteresis and the pinning force experienced by a droplet on a liquid infused surface, and our predictions for the critical sliding angles are consistent with existing experimental observations. Finally, we discuss why a droplet on a liquid infused surface with partially wetting lubricants typically experiences stronger pinning compared to a droplet on a classical superhydrophobic surface.
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Affiliation(s)
| | - Jack R Panter
- Department of Physics, Durham University, Durham, DH1 3LE, UK.
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91
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Mullagura HN, Dash S. Bubble-Induced Rupture of Droplets on Hydrophobic and Lubricant-Impregnated Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:8858-8864. [PMID: 32614589 DOI: 10.1021/acs.langmuir.0c01187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Bursting of bubbles is ubiquitous with numerous applications ranging from spraying of pesticides, drug delivery, and inkjet printing to forming emulsions. Understanding the parameters that influence the dynamics of bubble rupture is crucial to design systems with improved performance. Here, we experimentally investigate the behavior of air-bubble-induced rupture of a sessile droplet placed on hydrophobic and lubricant-impregnated surfaces (LIS). We demonstrate that the bubble dynamics inside a sessile droplet and subsequent rupture of the thinning film is dependent on the nature of the underlying substrate and the thermodynamic state of the droplet on the substrate. The growth of the bubble is shown to be dependent on the contact angle hysteresis of water and air on the substrate and the presence of a cloaking oil film around the water droplet. On a plain and textured surface with a high contact angle hysteresis, bubble-induced rupture initiates at the apex of the droplet. In the case of LIS that offers negligible pinning forces, the bubble-induced rupture of liquid shell initiates near the triple contact line. The dynamics of rupture of droplets placed on LIS is shown to be dependent on the viscosity of the impregnating and cloaking lubricant.
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Affiliation(s)
- Haritha N Mullagura
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Susmita Dash
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore 560012, India
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92
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Adera S, Alvarenga J, Shneidman AV, Zhang CT, Davitt A, Aizenberg J. Depletion of Lubricant from Nanostructured Oil-Infused Surfaces by Pendant Condensate Droplets. ACS NANO 2020; 14:8024-8035. [PMID: 32490664 DOI: 10.1021/acsnano.9b10184] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Due to recent advances in nanofabrication, phase-change condensation heat transfer has seen a renaissance. Compared to conventional heat transfer surfaces, nanostructured surfaces impregnated with chemically matched lubrication films (hereinafter referred to as "nanostructured lubricated surfaces") have been demonstrated to improve vapor-side phase-change condensation heat transfer by facilitating droplet nucleation, growth, and departure. While the presence of nanoscale roughness improves performance longevity by stabilizing the lubrication film via capillary forces, such enhancement is short-lived due to the eventual loss of lubrication oil by the departing droplets. The objective of this study is to characterize oil depletion caused by pendant droplets during condensation. For our study, we nanostructured, chemically functionalized, and lubricated horizontal copper tubes that are widely used in shell-and-tube heat exchangers in power plants and process industries. Using high-speed fluorescence imaging and thermogravimetric analysis, we show that shedding droplets exert a shear force on the oil in the wetting ridge at the water-oil interface. The viscous shear draws the lubrication film from the nanostructured surface onto the upper portion of the droplet and forms a ring-like oil skirt. Through detailed theoretical analysis, we show that the thickness of this oil skirt scales with the classical Landau-Levich-Derjaguin (LLD) theory for dip-coating. Our results reveal that droplets falling from horizontal tubes break unequally and leave behind small satellite droplets that retain the bulk of the oil in the wetting ridge. This observation is in stark contrast with the earlier description of droplets shedding from tilted flat plates where the entire oil-filled wetting ridge is demonstrated to leave the surface upon droplet departure. By selecting lubrication oils of varying viscosity and spreading coefficient, we provide evidence that the contribution of the wrapping layer to the rate of oil depletion is insignificant. Furthermore, we show that due to the nanoscale features on the tubes, nearly half of the lubrication film remains on the surface after 10 h of continuous steam condensation at ambient pressure, 23 °C, and 60% relative humidity, a 2-3-fold improvement over previous results.The insights gained from this work will provide guidelines for the rational design of long-lasting nanostructured lubricated surfaces for phase-change condensation.
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Affiliation(s)
- Solomon Adera
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Jack Alvarenga
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Anna V Shneidman
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Cathy T Zhang
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Alana Davitt
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Joanna Aizenberg
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, Massachusetts 02138, United States
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
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93
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Evaporating droplets on oil-wetted surfaces: Suppression of the coffee-stain effect. Proc Natl Acad Sci U S A 2020; 117:16756-16763. [PMID: 32616571 DOI: 10.1073/pnas.2006153117] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The evaporation of suspension droplets is the underlying mechanism in many surface-coating and surface-patterning applications. However, the uniformity of the final deposit suffers from the coffee-stain effect caused by contact line pinning. Here, we show that control over particle deposition can be achieved through droplet evaporation on oil-wetted hydrophilic surfaces. We demonstrate by flow visualization, theory, and numerics that the final deposit of the particles is governed by the coupling of the flow field in the evaporating droplet, the movement of its contact line, and the wetting state of the thin film surrounding the droplet. We show that the dynamics of the contact line can be tuned through the addition of a surfactant, thereby controlling the surface energies, which then leads to control over the final particle deposit. We also obtain an analytical expression for the radial velocity profile which reflects the hindering of the evaporation at the rim of the droplet by the nonvolatile oil meniscus, preventing flow toward the contact line, thus suppressing the coffee-stain effect. Finally, we confirm our physical interpretation by numerical simulations that are in qualitative agreement with the experiment.
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94
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Roy PK, Bormashenko E, Frenkel M, Legchenkova I, Shoval S. Magnetic field induced motion of water droplets and bubbles on the lubricant coated surface. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.124773] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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95
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Yang J, Li J, Jia X, Li Y, Song H. Fabrication of Robust and Transparent Slippery Coating with Hot Water Repellency, Antifouling Property, and Corrosion Resistance. ACS APPLIED MATERIALS & INTERFACES 2020; 12:28645-28654. [PMID: 32453938 DOI: 10.1021/acsami.0c06743] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Water-repellent coatings with low sliding angles for aqueous liquids are of great significance for practical applications. However, these coatings are susceptible to various types of damage during service and lose their effect. Herein, a robust and transparent slippery coating with extremely low water sliding angle was fabricated by covalently grafting polydimethylsiloxane (PDMS) brushes in a cross-linked skeleton of epoxy resin. Polyamidoamine G5.0 with 128 NH2 end groups was used as curing agent to induce the high cross-linking of the coating and the abundant PDMS brushes being grafted into it. Because of low surface energy and high mobility of PDMS brushes, the obtained coating exhibited a slippery performance for aqueous liquids (10 μL) with a sliding angle lower than 3° and a sliding speed as high as 1.16 mm/s. Even a 10 μL water droplet with temperature of 80 °C can slide off the coating at a low sliding angle (<5°). The strong intermolecular interactions of epoxy cross-linked skeleton endowed the coating with excellent physical and chemical stability. The sliding angle of the coating had no obvious change after heating at 120 °C for 100 h and placing outdoors for 7 months. The slippery performance was not affected by thumb press, knife scratching, high-speed friction, and water of different pH values. Furthermore, because of the excellent stability, antifouling performance, and corrosion resistance, the slippery coating can be applied to a variety of substrates, which makes the robust slippery coating have real potential for practical applications.
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Affiliation(s)
- Jin Yang
- School of Materials Science & Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science & Technology, Xi'an, Shaanxi 710021, P. R. China
| | - Jiayu Li
- Institute for Advanced Materials, School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, P. R. China
| | - Xiaohua Jia
- School of Materials Science & Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science & Technology, Xi'an, Shaanxi 710021, P. R. China
| | - Yong Li
- School of Materials Science & Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science & Technology, Xi'an, Shaanxi 710021, P. R. China
| | - Haojie Song
- School of Materials Science & Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science & Technology, Xi'an, Shaanxi 710021, P. R. China
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96
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Jamali M, Tafreshi HV. Measuring Force of Droplet Detachment from Hydrophobic Surfaces via Partial Cloaking with Ferrofluids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:6116-6125. [PMID: 32410450 DOI: 10.1021/acs.langmuir.0c00532] [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
This paper presents a new approach to measure the force required to detach a water (a polar liquid) droplet from a hydrophobic surface. This is done by partially cloaking the droplet with a high-surface-tension oil-based ferrofluid and using a magnet to apply a controllable body force to the resulting compound droplet. Placing the assembly on a sensitive scale, the magnet can then be brought closer to the droplet to detach it from the surface while recording the forces applied to the droplet. The work presented here is novel as it uses the concept of partial cloaking in which the solid-droplet contact area is not contaminated by the ferrofluid (and the measured forces do not need postprocessing). Our study is accompanied by numerical simulations aimed at improving our understanding of the interplay between the interfacial forces in a two-phase droplet under the influence of a strong (detaching) body force and at providing additional data for in-depth analyses of these forces. In particular, the minimum ferrofluid volume required for successful water droplet detachment from hydrophobic surfaces is computed for ferrofluids of different surface tensions, and they are compared to experimental data obtained from detaching water droplets from electrospun polystyrene coatings. It is also shown that the detachment force measured via partial cloaking is independent of the volume of the ferrofluid used for the experiment.
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Affiliation(s)
- Mohammad Jamali
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia 23284-3015, United States
| | - Hooman Vahedi Tafreshi
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, Virginia 23284-3015, United States
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97
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Sharma M, Mondal SS, Roy PK, Khare K. Evaporation dynamics of pure and binary mixture drops on dry and lubricant coated slippery surfaces. J Colloid Interface Sci 2020; 569:244-253. [DOI: 10.1016/j.jcis.2020.02.074] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 02/15/2020] [Accepted: 02/17/2020] [Indexed: 11/26/2022]
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98
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Yuan X, Tang B, Barman J, Groenewold J, Zhou G. Approximately symmetric electrowetting on an oil-lubricated surface. RSC Adv 2020; 10:20257-20263. [PMID: 35520452 PMCID: PMC9054235 DOI: 10.1039/d0ra02405h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 05/09/2020] [Indexed: 12/24/2022] Open
Abstract
As the most widely used insulator materials in the electrowetting (EW) systems, amorphous fluoropolymers (AFs) provide excellent hydrophobicity, dielectric properties and chemical inertness; however, they suffer from charge trapping during electrowetting with water and the consequent asymmetric phenomenon. In this study, an ultra-thin oil-lubricated AF surface was proposed to release the charge trapping in the dielectric layer and further suppress the polarity-dependent asymmetry during electrowetting. The negative spontaneously trapped charges gathering on the dielectric/water interface with aging time were characterized by various measurements and calculations, which explained the polarity dependence of the asymmetric electrowetting. Approximately symmetric EW curves withstanding water aging were obtained for the oil-lubricated AF surface, confirming the blocking effect on charge trapping induced by the lubricated surface. The improved reversibility of EW with low contact angle hysteresis brought by the oil-lubricated surface was also demonstrated. This study reveals the mechanism behind the asymmetric EW phenomenon and offers an attractive oil-lubricated EW material system for suppressing the charge trapping on the dielectric/water interface, which can significantly improve the manipulation of the EW devices.
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Affiliation(s)
- Xi Yuan
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, Institute of Electronic Paper Displays South China Academy of Advanced Optoelectronics, South China Normal University Guangzhou 510006 P. R. China .,National Center for International Research on Green Optoelectronics, South China Normal University Guangzhou 510006 P. R. China
| | - Biao Tang
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, Institute of Electronic Paper Displays South China Academy of Advanced Optoelectronics, South China Normal University Guangzhou 510006 P. R. China .,National Center for International Research on Green Optoelectronics, South China Normal University Guangzhou 510006 P. R. China
| | - Jitesh Barman
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, Institute of Electronic Paper Displays South China Academy of Advanced Optoelectronics, South China Normal University Guangzhou 510006 P. R. China .,National Center for International Research on Green Optoelectronics, South China Normal University Guangzhou 510006 P. R. China
| | - Jan Groenewold
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, Institute of Electronic Paper Displays South China Academy of Advanced Optoelectronics, South China Normal University Guangzhou 510006 P. R. China .,National Center for International Research on Green Optoelectronics, South China Normal University Guangzhou 510006 P. R. China.,Van't Hoff Laboratory for Physical and Colloid Chemistry, Debye Research Institute, Utrecht University Padualaan 8 3584 CH Utrecht The Netherlands
| | - Guofu Zhou
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, Institute of Electronic Paper Displays South China Academy of Advanced Optoelectronics, South China Normal University Guangzhou 510006 P. R. China .,National Center for International Research on Green Optoelectronics, South China Normal University Guangzhou 510006 P. R. China.,Academy of Shenzhen Guohua Optoelectronics Shenzhen 518110 P. R. China
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99
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Tian X, Banerjee S, Gonzalez-Alfonzo I, Cademartiri L. Suppressing Evaporative Loss in Slippery Liquid-Infused Porous Surfaces (SLIPS) with Self-Suspended Perfluorinated Nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:5106-5111. [PMID: 32311263 DOI: 10.1021/acs.langmuir.0c00160] [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
This article describes an approach to resolving the issue of evaporative loss from slippery liquid-infused porous surfaces (SLIPS). Hydrophobic and oleophobic fluids with significantly reduced evaporative loss rates at temperatures of up to 90 °C were obtained by the one-step mixing of commercially available perfluorinated lubricants with colloidal nanoparticles to form self-suspended nanoparticle fluids (i.e., suspensions nearly devoid of solvent). No evaporative loss was detected at temperatures of as high as 50 °C for over 3 months. Furthermore, the approach allows us to combine the function of the nanoparticles with the slippery characteristic of SLIPS.
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Affiliation(s)
| | | | | | - Ludovico Cademartiri
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
- Department of Chemistry, Life Sciences, and Environmental Sustainability, University of Parma, Parco Area delle Scienze, Parma, 43124, Italy
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100
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Ge Q, Raza A, Li H, Sett S, Miljkovic N, Zhang T. Condensation of Satellite Droplets on Lubricant-Cloaked Droplets. ACS APPLIED MATERIALS & INTERFACES 2020; 12:22246-22255. [PMID: 32306727 PMCID: PMC7304831 DOI: 10.1021/acsami.9b22417] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 04/19/2020] [Indexed: 06/11/2023]
Abstract
Condensation on lubricant-infused micro- or nanotextured superhydrophobic surfaces exhibits remarkable heat transfer performance owing to the high condensation nucleation density and efficient condensate droplet removal. When a low surface tension lubricant is used, it can spread on the condensed droplet and "cloak" it. Here, we describe a previously unobserved condensation phenomenon of satellite droplet formation on lubricant-cloaked water droplets using environmental scanning electron microscopy. The presence of satellite droplets confirms the cloaking behavior of common lubricants on water such as Krytox oils. More interestingly, we have observed satellite droplets on BMIm ionic liquid-infused surfaces, which is unexpected because BMIm was used in previous reports as a lubricant to eliminate cloaking during water condensation. Our studies reveal that the cloaking of BMIm on water droplets is theoretically favorable due to the fast timescale spreading during initial condensation when compared to the long timescale required for dissolution of the lubricant in water. We utilize a novel characterization approach based on Raman spectroscopy to confirm the existence of cloaking lubricant films on water droplets residing on lubricant-infused surfaces. The selected lubricants include Krytox oil, ionic liquid, and dodecane, which have drastically different surface tensions and polarities. In addition, spreading dynamics of cloaking and noncloaking lubricants on water droplets show that ionic liquid has the capability to mobilize water droplets spontaneously owing to cloaking and its relatively high surface tension. Our studies not only elucidate the physics governing cloaking and satellite droplet condensation phenomena at micro- and macroscales but also reveal a subset of previously unobserved lubricant-water interfacial interactions for a large variety of applications.
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Affiliation(s)
- Qiaoyu Ge
- Department
of Mechanical Engineering, Masdar Institute, Khalifa University of Science and Technology, P.O. Box 54224, Abu Dhabi, UAE
| | - Aikifa Raza
- Department
of Mechanical Engineering, Masdar Institute, Khalifa University of Science and Technology, P.O. Box 54224, Abu Dhabi, UAE
| | - Hongxia Li
- Department
of Mechanical Engineering, Masdar Institute, Khalifa University of Science and Technology, P.O. Box 54224, Abu Dhabi, UAE
| | - Soumyadip Sett
- Department
of Mechanical Science and Engineering, University
of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Nenad Miljkovic
- Department
of Mechanical Science and Engineering, University
of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department
of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Materials
Research Laboratory, University of Illinois
at Urbana-Champaign, Urbana, Illinois 61801, United States
- International
Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744
Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - TieJun Zhang
- Department
of Mechanical Engineering, Masdar Institute, Khalifa University of Science and Technology, P.O. Box 54224, Abu Dhabi, UAE
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