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Nosrati A, Mohammadshahi S, Raessi M, Ling H. Impact of the Undersaturation Level on the Longevity of Superhydrophobic Surfaces in Stationary Liquids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023. [PMID: 38011263 DOI: 10.1021/acs.langmuir.3c03006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Although the longevity of superhydrophobic surface (SHS) induced by diffusive gas transfer has been extensively studied, the scaling relation between SHS longevity and undersaturation level of the liquid is still an open question. In this study, we address this question by performing experiments where the plastron decay is visualized by a nonintrusive optical technique based on light reflection, the gas diffusion is introduced by using liquid with low dissolved gas concentrations, and the SHS longevity is measured based on the status of gas on the entire surface. We find that the SHS longevity (tf) follows a scaling relation: tf ∼ (1 - s)-2, where s is the ratio of the gas concentration in liquid to that in the plastron. This scaling relation implies that as the gas is dissolving into the liquid, mass flux J reduces with time as J ∼ t-0.5. Furthermore, we find that the diffusion length LD reduces as the undersaturation level increases, following the scaling relation of LD ∼ (1 - s)-1. Lastly, we show that an SHS with a greater texture depth has a longer longevity and a larger LD. Our results provide a better understanding of SHS longevity in undersaturated liquid.
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Affiliation(s)
- Ali Nosrati
- Department of Mechanical Engineering, University of Massachusetts Dartmouth, Dartmouth, Massachusetts 02747, United States
| | - Shabnam Mohammadshahi
- Department of Mechanical Engineering, University of Massachusetts Dartmouth, Dartmouth, Massachusetts 02747, United States
| | - Mehdi Raessi
- Department of Mechanical Engineering, University of Massachusetts Dartmouth, Dartmouth, Massachusetts 02747, United States
| | - Hangjian Ling
- Department of Mechanical Engineering, University of Massachusetts Dartmouth, Dartmouth, Massachusetts 02747, United States
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2
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Wang Y, Zhao R, He X, Zhang Z, Meng J, Wang S. Water Spider-Inspired Nanofiber Coating with Sustainable Scale Repellency via Air-Replenishing Strategy. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2209796. [PMID: 36652626 DOI: 10.1002/adma.202209796] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 01/02/2023] [Indexed: 06/17/2023]
Abstract
To survive underwater even in severely hypoxic water for a long period, the water spider has to periodically collect and replenish air into the diving bell. Inspired by this natural air-replenishing strategy, a water spider-inspired nanofiber (WSN) coating with underwater superaerophilicity displaying excellent and sustainable scalephobic capability is prepared. Air film on the WSN coating can be well-kept and further employed as the barrier layer for scale repellence. Significantly, scalephobic capability of the WSN coating mainly originates from two aspects: inhibiting interfacial nucleation and reducing interfacial adhesion of scale. Compared with previous studies, this WSN coating achieves excellent and sustainable scale repellence (≈ 98% reduction in scale deposition) even after a one-month dynamic scaling test. Thus, this air-replenishing strategy may raise a new avenue for advanced long-term scalephobic materials.
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Affiliation(s)
- Yixuan Wang
- CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences (UCAS), Beijing, 100049, P. R. China
| | - Ran Zhao
- CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences (UCAS), Beijing, 100049, P. R. China
| | - Xiao He
- CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences (UCAS), Beijing, 100049, P. R. China
| | - Zhe Zhang
- CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences (UCAS), Beijing, 100049, P. R. China
| | - Jingxin Meng
- CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences (UCAS), Beijing, 100049, P. R. China
- Binzhou Institute of Technology, Binzhou, 256600, P. R. China
| | - Shutao Wang
- CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences (UCAS), Beijing, 100049, P. R. China
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3
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Zhang Y, Hu Y, Xu B, Fan J, Zhu S, Song Y, Cui Z, Wu H, Yang Y, Zhu W, Wang F, Li J, Wu D, Chu J, Jiang L. Robust Underwater Air Layer Retention and Restoration on Salvinia-Inspired Self-Grown Heterogeneous Architectures. ACS NANO 2022; 16:2730-2740. [PMID: 35156798 DOI: 10.1021/acsnano.1c09669] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Salvinia's long-term underwater air layer retention ability has inspired researchers to develop artificial microstructures. However, Salvinia has an exquisite combination of a complicated hollow structure and heterogeneous chemical properties, which makes artificial reproduction beyond the capabilities of traditional fabrication techniques. In addition, under extremely low underpressure conditions, the mechanism of retention and restoration of the underwater air layer of Salvinia remains unclear. Herein, by combining the shape memory polymer "top-constrained self-branching (TCSB)" and hydrophilic SiO2 microspheres trapping, four-branch hollow microstructures with heterogeneous chemical properties are fabricated. By applying underpressure, the crucial role of hydrophilic apexes is unveiled in air layer restoration. Through the calculation of the surface energy, the underlying mechanism is well interpreted. This study holds great promise for developing Salvinia-inspired artificial structures and reveals the underlying mechanism of the robust air retention and recovery capability of Salvinia leaves in extreme environments.
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Affiliation(s)
- Yachao Zhang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230027, China
| | - Yanlei Hu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230027, China
| | - Bing Xu
- School of Mechanical Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Jianing Fan
- Department of Modern Mechanics, CAS Center for Excellence in Complex System Mechanics, University of Science and Technology of China, Hefei 230027, China
| | - Suwan Zhu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230027, China
| | - Yuegan Song
- Key Laboratory of Testing Technology for Manufacturing Process of Ministry of Education, Southwest University of Science and Technology, Mianyang 621010, China
| | - Zehang Cui
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230027, China
| | - Hao Wu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230027, China
| | - Yi Yang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230027, China
- Key Laboratory of Testing Technology for Manufacturing Process of Ministry of Education, Southwest University of Science and Technology, Mianyang 621010, China
| | - Wulin Zhu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230027, China
| | - Fengchao Wang
- Department of Modern Mechanics, CAS Center for Excellence in Complex System Mechanics, University of Science and Technology of China, Hefei 230027, China
| | - Jiawen Li
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230027, China
| | - Dong Wu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230027, China
| | - Jiaru Chu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230027, China
| | - Lei Jiang
- Key Laboratory of Bio-inspired Materials and Interface Sciences, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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Ahmadi SF, Umashankar V, Dean Z, Chang B, Jung S, Boreyko JB. How Multilayered Feathers Enhance Underwater Superhydrophobicity. ACS APPLIED MATERIALS & INTERFACES 2021; 13:27567-27574. [PMID: 34075745 DOI: 10.1021/acsami.1c04480] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Inspired by ducks, we demonstrate that air pockets within stacked layers of porous superhydrophobic feathers can withstand up to five times more water pressure compared to a single feather. In addition to natural duck feathers, this "layer effect" was replicated with synthetic feathers created by laser cutting micrometric slots into aluminum foil and imparting a superhydrophobic nanostructure. It was revealed that adding layers promotes an increasingly redundant pathway for water impalement, which serves to pressurize the enclosed air pockets. This was validated by creating a probabilistic pore impalement model and also by filling the feathers with an incompressible oil, rather than air, to suppress the layer effect. In addition to revealing a utility of natural duck feathers, our findings suggest that multilayered engineered surfaces can maintain air pockets at high pressures, useful for reducing the drag and fouling of marine structures or enhancing desalination membranes.
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Affiliation(s)
- S Farzad Ahmadi
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia 24061, United States
- Department of Mechanical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Viverjita Umashankar
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Zaara Dean
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Brian Chang
- Department of Physics, Clark University, Worcester, Massachusetts 01610, United States
| | - Sunghwan Jung
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Jonathan B Boreyko
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia 24061, United States
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5
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Zhu Y, Yang F, Guo Z. Bioinspired surfaces with special micro-structures and wettability for drag reduction: which surface design will be a better choice? NANOSCALE 2021; 13:3463-3482. [PMID: 33566874 DOI: 10.1039/d0nr07664c] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Human beings learn from creatures in nature and imitate them to solve challenges in daily life. Thus, the use of bioinspired surfaces for drag reduction has attracted extensive attention in recent years due to their important applications in many fields, such as pipeline systems, maritime transportation, and military weapons. Herein, we introduce some typical plants and animals with low drag surfaces that exist in nature, focusing on their drag reduction patterns. There are two main mechanisms to explain how surfaces reduce frictional drag, where one is to design a suitable surface geometry to change the flow distribution of surrounding fluid and the other is to introduce a low friction lubricating layer (usually air or non-toxic silicone oil) to partially or completely replace the solid-liquid interface. Hence, by mimicking these organisms, some surfaces have been fabricated to reduce frictional drag, including riblets, superhydrophobic surfaces, and slippery liquid-infused porous surfaces. With the increasing research on drag-reducing surfaces, the drag reduction rate of different types of surface designs has greatly improved in recent years. This review provides a holistic overview that facilitates direct comparisons between these surface types. To select an optimal surface for drag reduction in practical applications, the merits and deficiencies of different surface designs are analysed and compared. Finally, based on the current challenges, we present some future prospects for the application of bioinspired surfaces in drag reduction.
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Affiliation(s)
- Yi Zhu
- Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, School of Materials Science & Engineering and Hubei Key Laboratory of Polymer Materials, Hubei University, Wuhan 430062, China.
| | - Fuchao Yang
- Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, School of Materials Science & Engineering and Hubei Key Laboratory of Polymer Materials, Hubei University, Wuhan 430062, China.
| | - Zhiguang Guo
- Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, School of Materials Science & Engineering and Hubei Key Laboratory of Polymer Materials, Hubei University, Wuhan 430062, China. and State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
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6
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Pendyala P, Kim HN, Ryu YS, Yoon ES. Time-Dependent Wetting Scenarios of a Water Droplet on Surface-Energy-Controlled Microcavity Structures with Functional Nanocoatings. ACS APPLIED MATERIALS & INTERFACES 2020; 12:39881-39891. [PMID: 32805947 DOI: 10.1021/acsami.0c10618] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We report the surface-energy-dependent wetting transition characteristics of an evaporating water droplet on surface-energy-controlled microcavity structures with functional nanocoatings. The droplet wetting scenarios were categorized into four types depending on the synergistic effect of surface energy and pattern size. The silicon (Si) microcavity surfaces (γSi = 69.8 mJ/m2) and the polytetrafluoroethylene (PTFE)-coated microcavity surfaces (γPTFE = 15.0 mJ/m2) displayed stable Wenzel and Cassie wetting states, respectively, irrespective of time. In contrast, diamond-like carbon (DLC)-coated (γDLC = 55.5 mJ/m2) and fluorinated diamond-like carbon (FDLC)-coated (γFDLC = 36.2 mJ/m2) surfaces demonstrated a time-dependent transition of wetting states. In particular, the DLC-coated surface showed random filling of microcavities at the earlier time point, while the FDLC-coated surface displayed directional filling of microcavities at the late stage of drop evaporation. Such dynamic wetting scenarios based on surface energy, in particular, the random and directional wetting transitions related to surface energy of nanocoatings have not been explored previously. Furthermore, the microscopic role of nanocoating in the wetting scenarios was analyzed by monitoring the time-dependent deformation and movement of the air-water interface (AWI) at individual cavities using the fluorescence interference-contrast (FLIC) technique. A coating-dependent depinning mechanism of the AWI was responsible for variable filling of cavities leading to time-dependent wetting scenarios. A capillary wetting model was used to relate this depinning event to the evaporation-induced internal flow within the droplet. Interestingly, FLIC analysis revealed that a hydrophilic nanocoating can induce microscopic hydrophobicity near the cavity edges leading to delayed and variable cavity filling. The surface energy-dependent classification of the wetting scenarios may help the design of novel evaporation-assisted thermodynamic and mass-transfer processes.
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Affiliation(s)
- Prashant Pendyala
- Center for BioMicrosystems, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Hong Nam Kim
- Center for BioMicrosystems, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Republic of Korea
| | - Yong-Sang Ryu
- Sensor System Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Eui-Sung Yoon
- Center for BioMicrosystems, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
- Division of Nano & Information Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Republic of Korea
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Varughese SM, Bhandaru N. Durability of submerged hydrophobic surfaces. SOFT MATTER 2020; 16:1692-1701. [PMID: 31967169 DOI: 10.1039/c9sm01942a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Hydrophobic and superhydrophobic surfaces have gained wide popularity due to their potential in various areas such as in self-cleaning and anti-fouling materials, drag reduction and microfluidics. However, for all practical applications, the long term durability of these surfaces is extremely important, yet not often investigated. Of particular interest is the long term durability of soft hydrophobic surfaces that remain submerged underwater for a prolonged duration. In this article, we explore how the chemical durability of flat and patterned crosslinked PDMS surfaces (polydimethylsiloxane, a preferred material for microfabrication) change as a function of time when submerged in acidic, basic and neutral media for different durations over a prolonged period of time. Based on contact angle measurements, atomic force microscopy, confocal microscopy and SEM analysis of the surfaces, we checked if there is any change in the morphology of the surface due to deposition or etching. We created a biomimetic positive replica of a lotus leaf that exhibited super-hydrophobicity and Cassie state of wetting with a static water contact angle (θ) > 150°, and compared the degradation with a negative replica of lotus leaf (θ ∼ 127°), a grating patterned surface that exhibited Wenzel state of wetting (θ ∼ 110°) and a flat crosslinked PDMS surface (θ ∼ 105°). The positive replica maintained reasonable hydrophobicity (θ > 90°) for up to a month, but lost its super-hydrophobic property. The surface hydrophobicity degraded the most in the case of basic solution due to deposition.
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Affiliation(s)
- Sharon Mariam Varughese
- Department of Chemical Engineering, Birla Institute of Technology and Science Pilani, Hyderabad Campus, 500 078, Telangana, India.
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8
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Zhang S, Liang X, Gadd GM, Zhao Q. Superhydrophobic Coatings for Urinary Catheters To Delay Bacterial Biofilm Formation and Catheter-Associated Urinary Tract Infection. ACS APPLIED BIO MATERIALS 2019; 3:282-291. [DOI: 10.1021/acsabm.9b00814] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Shuai Zhang
- School of Science and Engineering, University of Dundee, Dundee DD1 4HN, Scotland, U.K
| | - Xinjin Liang
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, U.K
| | | | - Qi Zhao
- School of Science and Engineering, University of Dundee, Dundee DD1 4HN, Scotland, U.K
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9
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Tian C, Wang X, Liu Y, Yang W, Hu H, Pei X, Zhou F. In Situ Grafting Hydrophilic Polymeric Layer for Stable Drag Reduction. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:7205-7211. [PMID: 31083953 DOI: 10.1021/acs.langmuir.9b00321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Developing drag reduction techniques has attracted great attention because of their need in practical applications. However, many of the proposed strategies exhibit some inevitable limitations, especially for long period of adhibition. In this work, the dynamic but stable drag reduction effect of superhydrophilic hydrogel-coated iron sphere falling freely in a cylindrical water tank was investigated. The absolute instantaneous velocities and displacements of either the hydrogel-encapsulated or unmodified iron sphere falling freely in water were monitored via a high-speed video. It was revealed that, in the range of Reynolds number from 104 to 106, the optimized hydrogel-coated iron sphere with uniform stability could reduce the resistance by up to 40%, which was mainly due to the boundary slip of water and the delayed boundary separation that resulted from the coated hydrogel. Besides, the deliberate experiments and analysis further indicated that the superhydrophilic hydrogel layer accompanied by the emergence of the drag crisis has largely effected the distribution of flow field at the boundary around the sphere. More importantly, the drag reduction behavior based on the proposed method was thermodynamically stable and resistant to external stimulus, including fluidic oscillator and hydrodynamic pressure. The effective long-term drag reduction performance of the hydrophilic substrate can be expected, correspondingly, and also provides a novel preliminary protocol and avenues for the development of durable drag reduction technologies.
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Affiliation(s)
- Chaoguo Tian
- School of Mechatronics Engineering , Nanchang University , Nanchang 330031 , China
| | | | - Ying Liu
- School of Mechatronics Engineering , Nanchang University , Nanchang 330031 , China
| | - Wufang Yang
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics , Chinese Academy of Sciences , Tianshui Middle Rd , Lanzhou 730000 , China
| | | | | | - Feng Zhou
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics , Chinese Academy of Sciences , Tianshui Middle Rd , Lanzhou 730000 , China
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10
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Malkin AY, Patlazhan SA. Wall slip for complex liquids - Phenomenon and its causes. Adv Colloid Interface Sci 2018; 257:42-57. [PMID: 29934140 DOI: 10.1016/j.cis.2018.05.008] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 05/27/2018] [Accepted: 05/28/2018] [Indexed: 11/28/2022]
Abstract
In this review, we tried to qualify different types and mechanisms of wall slip phenomenon, paying particular attention to the most recent publications and issues. The review covers all type of fluids - homogeneous low molecular weight liquids, polymer solution, multi-component dispersed media, and polymer melts. We focused on two basic concepts - fluid-solid wall interaction and shear-induced fluid-to-solid transitions - which are the dominant mechanisms of wall slip. In the first part of the review, the theoretical and numerical studies of correlation of wetting properties and wall slip of low molecular weight liquids and polymeric fluids are reviewed along with some basic experimental results. The influence of nanobubbles and microcavities on the effectiveness of wall slip is illuminated with regard to the bubble dynamics, as well as their stability at smooth and rough interfaces, including superhydrophobic surfaces. Flow of multi-component matter (microgel pastes, concentrated suspensions of solid particles, compressed emulsions, and colloidal systems) is accompanied by wall slip in two cases. The first one is typical of viscoplastic media which can exist in two different physical states, as solid-like below the yield point and liquid-like at the applied stresses exceeding this threshold. Slip takes place at low stresses. The second case is related to the transition from fluid to solid states at high deformation rates or large deformations caused by the strain-induced glass transition of concentrated dispersions. In the latter case, the wall effects consist of apparent slip due to the formation of a low viscous thin layer of fluid at the wall. The liquid-to-solid transition is also a dominant mechanism in wall slip of polymer melts because liquid polymers are elastic fluids which can be in two relaxation states depending on the strain rate. The realization of these mechanisms is determined by polymer melt interaction with the solid wall.
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Affiliation(s)
- A Ya Malkin
- Russian Academy of Sciences, Institute of Petrochemical Synthesis, 29, Leninski Prospect, Moscow 119991, Russia.
| | - S A Patlazhan
- Russian Academy of Sciences, Semenov Institute of Chemical Physics, 4, Kosygin Street, Moscow 119991, Russia; Russian Academy of Sciences, Institute of Problems of Chemical Physics, 1, Semenov Avenue, Chernogolovka, Moscow 142432, Russia
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11
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Jain R, Pitchumani R. Facile Fabrication of Durable Copper-Based Superhydrophobic Surfaces via Electrodeposition. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:3159-3169. [PMID: 29045147 DOI: 10.1021/acs.langmuir.7b02227] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Superhydrophobic surfaces have myriad industrial applications, yet their practical utilization has been limited by their poor mechanical durability and longevity. We present a low-cost, facile process to develop superhydrophobic copper-based coatings via an electrodeposition route, that addresses this limitation. Through electrodeposition, a stable, multiscale, cauliflower shaped fractal morphology was obtained and upon modification by stearic acid, the prepared coatings show extreme water repellency with contact angle of 162 ± 2° and roll-off angle of about 3°. Systematic studies are presented on coatings fabricated under different processing conditions to demonstrate good durability, mechanical and underwater stability, corrosion resistance, and self-cleaning effect. The study also presents an approach for rejuvenation of slippery superhydrophobic nature (roll-off angle <10°) on the surfaces after long-term water immersion. The presented process can be scaled to larger, durable coatings with controllable wettability for diverse applications.
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Affiliation(s)
- R Jain
- Advanced Materials and Technologies Laboratory, Department of Mechanical Engineering , Virginia Tech , Blacksburg , Virginia 24061-0238 , United States
| | - R Pitchumani
- Advanced Materials and Technologies Laboratory, Department of Mechanical Engineering , Virginia Tech , Blacksburg , Virginia 24061-0238 , United States
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12
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Xiang Y, Huang S, Lv P, Xue Y, Su Q, Duan H. Ultimate Stable Underwater Superhydrophobic State. PHYSICAL REVIEW LETTERS 2017; 119:134501. [PMID: 29341680 DOI: 10.1103/physrevlett.119.134501] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Indexed: 05/03/2023]
Abstract
Underwater metastability hinders the durable application of superhydrophobic surfaces. In this work, through thermodynamic analysis, we theoretically demonstrate the existence of an ultimate stable state on underwater superhydrophobic surfaces. Such a state is achieved by the synergy of mechanical balance and chemical diffusion equilibrium across the entrapped liquid-air interfaces. By using confocal microscopy, we in situ examine the ultimate stable states on structured hydrophobic surfaces patterned with cylindrical micropores in different pressure and flow conditions. The equilibrium morphology of the meniscus is tuned by the dissolved gas saturation degree within a critical range at a given liquid pressure. Moreover, with fresh lotus leaves, we prove that the ultimate stable state can also be realized on randomly rough superhydrophobic surfaces. The finding here paves the way for applying superhydrophobic surfaces in environments with different liquid pressure and flow conditions.
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Affiliation(s)
- Yaolei Xiang
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Shenglin Huang
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Pengyu Lv
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Yahui Xue
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Qiang Su
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Huiling Duan
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China
- CAPT, HEDPS and IFSA Collaborative Innovation Center of MoE, Peking University, Beijing 100871, People's Republic of China
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13
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Domingues EM, Arunachalam S, Mishra H. Doubly Reentrant Cavities Prevent Catastrophic Wetting Transitions on Intrinsically Wetting Surfaces. ACS APPLIED MATERIALS & INTERFACES 2017; 9:21532-21538. [PMID: 28580784 DOI: 10.1021/acsami.7b03526] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Omniphobic surfaces, that is, which repel all known liquids, have proven of value in applications ranging from membrane distillation to underwater drag reduction. A limitation of currently employed omniphobic surfaces is that they rely on perfluorinated coatings, increasing cost and environmental impact and preventing applications in harsh environments. Thus, there is a keen interest in rendering conventional materials, such as plastics, omniphobic by micro/nanotexturing rather than via chemical makeup, with notable success having been achieved for silica surfaces with doubly reentrant micropillars. However, we found a critical limitation of microtextures comprising pillars that they undergo catastrophic wetting transitions (apparent contact angles, θr → 0° from θr > 90°) in the presence of localized physical damages/defects or on immersion in wetting liquids. In response, a doubly reentrant cavity microtexture is introduced, which can prevent catastrophic wetting transitions in the presence of localized structural damage/defects or on immersion in wetting liquids. Remarkably, our silica surfaces with doubly reentrant cavities could exhibit apparent contact angles, θr ≈ 135° for mineral oil, where the intrinsic contact angle, θo ≈ 20°. Further, when immersed in mineral oil or water, doubly reentrant microtextures in silica (θo ≈ 40° for water) were not penetrated even after several days of investigation. Thus, microtextures comprising doubly reentrant cavities might enable applications of conventional materials without chemical modifications, especially in scenarios that are prone to localized damages or immersion in wetting liquids, for example, hydrodynamic drag reduction and membrane distillation.
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Affiliation(s)
- Eddy M Domingues
- Water Desalination and Reuse Center (WDRC) and Biological and Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Sankara Arunachalam
- Water Desalination and Reuse Center (WDRC) and Biological and Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Himanshu Mishra
- Water Desalination and Reuse Center (WDRC) and Biological and Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
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Hokmabad BV, Ghaemi S. Effect of Flow and Particle-Plastron Collision on the Longevity of Superhydrophobicity. Sci Rep 2017; 7:41448. [PMID: 28128296 PMCID: PMC5269735 DOI: 10.1038/srep41448] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 12/19/2016] [Indexed: 01/27/2023] Open
Abstract
Among diverse methods for drag reduction, superhydrophobicity has shown considerable promise because it can produce a shear-free boundary without energy input. However, the plastron experiences a limited lifetime due to the dissolution of trapped air from surface cavities, into the surrounding water. The underwater longevity of the plastron, as it is influenced by environmental conditions, such as fine particles suspended in the water, must be studied in order to implement superhydrophobicity in practical applications. We present a proof-of-concept study on the kinetics of air loss from a plastron subjected to a canonical laminar boundary layer at Reδ = 1400 and 1800 (based on boundary layer thickness) with and without suspending 2 micron particles with density of 4 Kg/m3. To monitor the air loss kinetics, we developed an in situ non-invasive optical technique based on total internal reflection at the air-water interface. The shear flow at the wall is characterized by high resolution particle image velocimetry technique. Our results demonstrate that the flow-induced particle-plastron collision shortens the lifetime of the plastron by ~50%. The underlying physics are discussed and a theoretical analysis is conducted to further characterize the mass transfer mechanisms.
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Affiliation(s)
- Babak Vajdi Hokmabad
- Department of Mechanical Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada
| | - Sina Ghaemi
- Department of Mechanical Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada
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