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Mo M, Bai X, Liu Z, Huang Z, Xu M, Ma L, Lai W, Mo Q, Xie S, Li Y, Huang Y, Xiao N, Zheng Y. Defect by design: Harnessing the "petal effect" for advanced hydrophobic surface applications. J Colloid Interface Sci 2024; 673:37-48. [PMID: 38875796 DOI: 10.1016/j.jcis.2024.05.192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 05/15/2024] [Accepted: 05/24/2024] [Indexed: 06/16/2024]
Abstract
HYPOTHESIS In the interfacial wetting boundary, the superhydrophobic surface is often damaged, and the anisotropic wettability of its surface has attracted many researchers' attention. The "petal effect" surface has typical anisotropic wettability. We predict that under the dual conditions of structural defects and high impact velocity, the "petal effect" becomes more adhesive on the surface. EXPERIMENTS This study refers to the droplet state on rose petals, structural defects were constructed on the superhydrophobic surface. This paper studies the influence of macro-structural defects on the wettability change from natural to bionic "lotus effect" to "petal effect" in both static and dynamic angles. FINDINGS Macro defects significantly change the static contact angle of the superhydrophobic surface. The higher the impact velocity of the droplet, the higher the energy dissipation of the "petal effect" surface (DSHS), which improves the adhesion of the surface to the droplet and prolongs the contact time. It is found that the defect structure and high impact velocity will directly affect the deposition and desorption of droplets on the superhydrophobic surface, and they are both essential. This wetting dynamic law is very likely to be helpful in the quantitative design of defect structure scale for dynamic desorption of droplets on superhydrophobic surfaces.
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Affiliation(s)
- Min Mo
- College of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
| | - Xingjia Bai
- College of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
| | - Zhonglin Liu
- Guangxi Key Laboratory of Advanced Microwave Manufacturing Technology, Advanced Materials Industry Institute of Guangxi Academy of Science, Guangxi Academy of Sciences, Nanning 530007, China
| | - Zhimin Huang
- Guangxi Key Laboratory of Advanced Microwave Manufacturing Technology, Advanced Materials Industry Institute of Guangxi Academy of Science, Guangxi Academy of Sciences, Nanning 530007, China
| | - Mengxue Xu
- Guangxi Key Laboratory of Advanced Microwave Manufacturing Technology, Advanced Materials Industry Institute of Guangxi Academy of Science, Guangxi Academy of Sciences, Nanning 530007, China
| | - Lanyu Ma
- Guangxi Key Laboratory of Advanced Microwave Manufacturing Technology, Advanced Materials Industry Institute of Guangxi Academy of Science, Guangxi Academy of Sciences, Nanning 530007, China
| | - Wenqin Lai
- Guangxi Key Laboratory of Advanced Microwave Manufacturing Technology, Advanced Materials Industry Institute of Guangxi Academy of Science, Guangxi Academy of Sciences, Nanning 530007, China
| | - Qiufeng Mo
- Guangxi Key Laboratory of Advanced Microwave Manufacturing Technology, Advanced Materials Industry Institute of Guangxi Academy of Science, Guangxi Academy of Sciences, Nanning 530007, China
| | - Songbo Xie
- Guangxi Key Laboratory of Advanced Microwave Manufacturing Technology, Advanced Materials Industry Institute of Guangxi Academy of Science, Guangxi Academy of Sciences, Nanning 530007, China
| | - Yanming Li
- Guangxi Key Laboratory of Advanced Microwave Manufacturing Technology, Advanced Materials Industry Institute of Guangxi Academy of Science, Guangxi Academy of Sciences, Nanning 530007, China
| | - Yifeng Huang
- Guangxi Key Laboratory of Advanced Microwave Manufacturing Technology, Advanced Materials Industry Institute of Guangxi Academy of Science, Guangxi Academy of Sciences, Nanning 530007, China
| | - Ning Xiao
- National Key Laboratory of Non-Food Biomass Energy Technology, Guangxi Academy of Sciences, Nanning 530007, China
| | - Yihua Zheng
- Guangxi Key Laboratory of Advanced Microwave Manufacturing Technology, Advanced Materials Industry Institute of Guangxi Academy of Science, Guangxi Academy of Sciences, Nanning 530007, China.
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2
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Gu H, Jia Z, Zhou Q, Mu H, Chen F. Dynamic Behavior of Viscous Droplets Impact on a Flexible Mesh Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:12107-12116. [PMID: 38820070 DOI: 10.1021/acs.langmuir.4c00935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2024]
Abstract
The dynamic behavior of a viscous droplet impacting a flexible mesh surface with a fixed end is studied by high-speed photography in this work. Our experimental results reveal that surface vibration occurs when the viscous droplet impacts the flexible mesh surface. Simultaneously, the droplet spreads on the upper surface and penetrates into the mesh surface, resulting in a decrease in the spreading diameter on the upper surface. On the lower surface, the droplet elongates and forms multiple ligaments. Notably, different dynamic behaviors are observed when the droplet impacts surfaces with varying Weber (We) numbers due to viscous dissipation and surface vibration. However, as the impact position deviates from the fixed end, the surface vibrational amplitude increases, leading to a decreased diffusion range of the droplet on the lower surface. In addition, the vibration amplitude significantly enhances with increase of the We number. The vibration induces stretching and eventual rupture of the cardinal ligament under specific conditions. The first breaking time of the cardinal ligament delays with the decrease of the We number. As the impact position moves away from the fixed end, this situation is enhanced. Especially, when the stretching direction of the ligament is inconsistent with the vibration direction of the surface, the vibration has a great influence on the stretching behavior of the cardinal ligament.
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Affiliation(s)
- Hao Gu
- School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Zhihai Jia
- School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Qianbing Zhou
- School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Hailin Mu
- School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Feng Chen
- School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
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3
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Hosseini SR, Moghimi M, Nouri NM. On the role of surface morphology in impacting-freezing dynamics of supercooled droplets. Sci Rep 2024; 14:12585. [PMID: 38821975 PMCID: PMC11143377 DOI: 10.1038/s41598-024-61826-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Accepted: 05/10/2024] [Indexed: 06/02/2024] Open
Abstract
A thorough understanding of droplet impact and freezing is vital in preventing ice accretion on many outdoor devices. This simulation-based study investigated the effect of surface morphology on the impacting-freezing process of a supercooled droplet. Also, the variations of Weber number and supercooling temperature were studied numerically. The droplet impact and freezing process were simulated with the volume of fluid method and freezing model. A more accurate simulation was achieved by modeling the supercooled droplet and the dynamic contact angle. At the given ranges of the input parameters, the main factors that guaranteed droplet rebounding after collision were determined. The supercooling temperature and the groove width should be above 266 K and less than 0.21 mm, respectively. The droplet should also maintain its cohesion and integrity during impact. Creating grooves on a surface is novel and paves a new way to understand the impact and solidification of water droplets in supercooled conditions.
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Affiliation(s)
- S R Hosseini
- School of Mechanical Engineering, Iran University of Science and Technology, Tehran, 13114-16846, Iran
| | - M Moghimi
- School of Mechanical Engineering, Iran University of Science and Technology, Tehran, 13114-16846, Iran.
| | - N M Nouri
- School of Mechanical Engineering, Iran University of Science and Technology, Tehran, 13114-16846, Iran
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4
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Qian C, Li X, Li Q, Chen X. Nanofluid Droplet Impact on Rigid and Elastic Superhydrophobic Surfaces. ACS OMEGA 2024; 9:22003-22015. [PMID: 38799373 PMCID: PMC11112574 DOI: 10.1021/acsomega.3c10409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 04/12/2024] [Accepted: 04/17/2024] [Indexed: 05/29/2024]
Abstract
Ice accumulation on cold surfaces is a common and serious phenomenon that exists in numerous industrial fields, such as power transmission, wind turbines, and aircraft. Despite recent efforts in mitigating ice accumulation on the cold surface, it remains a challenge to achieve robust anti-icing on the cold surface in terms of nanofluid droplet. Here, we report a rigid superhydrophobic Cu surface and an elastic polydimethylsiloxane (PDMS) superhydrophobic surface to enhance water-repellency performance, characterized by a significant reduction in contact time and a decrease in the spreading ratio. As for the rigid superhydrophobic Cu surface, the underlying mechanism is ascribed to the existence of stable air cushions between the micropillar array, which reduce the contact area and further suppress the heat conduction. As for the elastic PDMS superhydrophobic surface, the rapid detachment of the nanofluid droplet relies on superior surface elasticity, which can further suppress the nanofluid droplet splashing at a high impacting velocity. We believe that this work can provide a new view for the improvement of water-repellency for a wide range of applications.
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Affiliation(s)
| | | | - Qiang Li
- MIIT Key Laboratory of Thermal Control
of Electronic Equipment, School of Energy and Power Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Xuemei Chen
- MIIT Key Laboratory of Thermal Control
of Electronic Equipment, School of Energy and Power Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
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5
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Misiiuk K, Willmott GR, Blaikie RJ, Sommers AD, Pandian SK, Lowrey S. Surveying the Directional Transport of Water Droplets upon Impact on Metallic Topographic Gradients. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 38661297 DOI: 10.1021/acsami.4c02773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Drop impact phenomena on raw, polished, and topography-altered gradient surfaces are investigated and presented. The main aim of this study is to demonstrate that in using a one-step industrial patterning process, it is possible to obtain metal topographical wetting gradients that can produce various desired outcomes after droplet impact. The findings could be applied to improving wind or steam turbine blades. The ranges of Weber (We) and Reynolds (Re) numbers in the study are 3-300 and 650-6500, respectively. It is demonstrated that for a fixed We, the droplet transport outcomes change from bouncing-off to side-flipping to deposition depending on the impact location and the gradient strength. The effect of We in combination with the gradient strength was also considered to demonstrate droplet behavior similar to that observed on a uniform water repellent surface and on biphilic systems. In addition, full bouncing-off and directional control have been demonstrated. For the condition We = 95 ± 3, it was possible to achieve a maximum droplet recoil height of ∼6 mm and a side motion of almost 8 mm. A combination of different outcomes (e.g., splashing on one side of a droplet and passive horizontal translation on another) was observed on the studied gradients at We > 200 due to different wetting regimes across the droplet's three-phase line.
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Affiliation(s)
- Kirill Misiiuk
- Department of Physics, University of Otago, Dunedin, Otago 9016, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Dunedin, Otago 9016, New Zealand
- Dodd-Walls Centre for Photonic and Quantum Technologies, Dunedin, Otago 9016, New Zealand
| | - Geoff R Willmott
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Dunedin, Otago 9016, New Zealand
- Department of Physics, University of Auckland, Auckland 1010, New Zealand
- School of Chemical Sciences, University of Auckland, Auckland 1010, New Zealand
| | - Richard J Blaikie
- Department of Physics, University of Otago, Dunedin, Otago 9016, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Dunedin, Otago 9016, New Zealand
- Dodd-Walls Centre for Photonic and Quantum Technologies, Dunedin, Otago 9016, New Zealand
| | - Andrew D Sommers
- Department of Mechanical & Manufacturing Engineering, Miami University, Oxford, Ohio 45056, United States
| | - Santhosh Kumar Pandian
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Dunedin, Otago 9016, New Zealand
- Department of Physics, University of Auckland, Auckland 1010, New Zealand
| | - Sam Lowrey
- Department of Physics, University of Otago, Dunedin, Otago 9016, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Dunedin, Otago 9016, New Zealand
- Dodd-Walls Centre for Photonic and Quantum Technologies, Dunedin, Otago 9016, New Zealand
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6
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Zhong X, Xie S, Guo Z. The Challenge of Superhydrophobicity: Environmentally Facilitated Cassie-Wenzel Transitions and Structural Design. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2305961. [PMID: 38145324 PMCID: PMC10933658 DOI: 10.1002/advs.202305961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 10/02/2023] [Indexed: 12/26/2023]
Abstract
Superhydrophobic materials can be used in various fields to optimize production and life due to their unique surface wetting properties. However, under certain pressure and perturbation conditions, the droplets deposited on superhydrophobic materials are prone to change from Cassie state to Wenzel state, which limits the practical applications of the materials. In recent years, a large number of works have investigated the transition behavior, transition mechanism, and influencing factors of the wetting transition that occurs when a superhydrophobic surface is under a series of external environments. Based on these works, in this paper, the phenomenon and kinetic behavior of the destruction of the Cassie state and the mechanism of the wetting transition are systematically summarized under external conditions that promote the wetting transition on the material surface, including pressure, impact, evaporation, vibration, and electric wetting. In addition, superhydrophobic surface morphology has been shown to directly affect the duration of the Cassie state. Based on the published work the effects of specific morphology on the Cassie state, including structural size, structural shape, and structural level, are summarized in this paper from theoretical analyses and experimental data.
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Affiliation(s)
- Xin Zhong
- Ministry of Education Key Laboratory for the Green Preparation and Application of Functional MaterialsHubei UniversityWuhan430062China
| | - Shangzhen Xie
- Ministry of Education Key Laboratory for the Green Preparation and Application of Functional MaterialsHubei UniversityWuhan430062China
| | - Zhiguang Guo
- Ministry of Education Key Laboratory for the Green Preparation and Application of Functional MaterialsHubei UniversityWuhan430062China
- State Key Laboratory of Solid LubricationLanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou730000China
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7
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Kumar B, Upadhyay G, Bhardwaj R. Coupled Dynamics of Droplet Impact on a Flexible, Hydrophilic Cantilever Beam. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:18768-18783. [PMID: 38095945 DOI: 10.1021/acs.langmuir.3c02238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
We experimentally study the droplet impact on a flexible, hydrophilic cantilever beam. Droplets of water, water-glycerol (1:1 v/v), and glycerol were considered on a copper beam. Side visualization of the droplet impact on the cantilever was carried out by using a high-speed camera. We systematically vary cantilever stiffness to obtain a characteristic time scale of the beam dynamics, that is, shorter on the same order and longer than the characteristic time scale of droplet dynamics. Water droplet spreading reduces with an increase in the beam's flexibility, due to the "springboard effect". Results reveal that a threshold cantilever length exists beyond which the droplet vibration mode "locks-in" to the cantilever vibration mode. During lock-in, the bending energy of the beam increases with an increasing length or decreasing stiffness. The time-varying cantilever deflection exhibits an oscillatory, exponentially decaying response. However, in the case where both time scales are almost the same, we found a two-stage damping in the measurements: a fast, initial damping followed by a slower, damped response. We explain this damped response by the interplay of droplet and cantilever early dynamics. As expected, increasing the droplet viscosity dampens the magnitude of droplet spreading and displacement of the cantilever's tip due to a larger dissipation of kinetic energy in the bulk of the droplet. The decay is exponential in all cases, and the time taken to reduce the spreading and displacement is shorter with a larger viscosity. The damping coefficient is found to inversely scale with the cantilever length or mass. We corroborated the measurements with available analytical models, confirming the hypotheses used to explain the results. Overall, the present study provides fundamental insights into controlling the coupled dynamics of droplet and flexible substrates, with potential applications such as the design of efficient agricultural sprays and wings of microaerial vehicles.
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Affiliation(s)
- Bibek Kumar
- Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Gaurav Upadhyay
- Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Rajneesh Bhardwaj
- Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, India
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8
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Kam D, Gwon G, Jang S, Yoo D, Park SJ, La M, Choi D. Advancing Energy Harvesting Efficiency from a Single Droplet: A Mechanically Guided 4D Printed Elastic Hybrid Droplet-Based Electricity Generator. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2303681. [PMID: 37527527 DOI: 10.1002/adma.202303681] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 07/08/2023] [Indexed: 08/03/2023]
Abstract
A droplet possesses the ubiquity and potential to harvest a vast amount of energy. To exploit droplets effectively, a novel output enhancement strategy that can coexist and create synergy with the recently studied droplet-based electricity generator (DEG) and material/surface structure modification must be investigated. In this study, a mechanical buckling-based 4D printed elastic hybrid droplet-based electricity generator (HDEG) consisting of a DEG and solid-solid triboelectric nanogenerator (S-S TENG) is first presented. During the electricity generation process of the DEG by droplet impact, the HDEG structure, which is merged via a simple 4D printing technique, permits the conversion of dissipated energy into elastic energy, resulting in an S-S TENG output. The HDEG outputs are naturally integrated owing to the simultaneous activation of a single droplet, resulting in an approximately 30% improvement over the output of a single DEG. Internal and external parametric studies are performed as HDEG design guidelines. The HDEG exhibits a 25% better energy supply performance than that of a single DEG, demonstrating its applicability as a power source. This research proposes the way toward a hybrid system that efficiently harvests energy from ubiquitous droplets.
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Affiliation(s)
- Dongik Kam
- Department of Mechanical Engineering (Integrated Engineering Program), Kyung Hee University, 1732 Deogyeong-daero, Yongin, Gyeonggi, 17104, South Korea
| | - Girak Gwon
- Department of Mechanical Engineering (Integrated Engineering Program), Kyung Hee University, 1732 Deogyeong-daero, Yongin, Gyeonggi, 17104, South Korea
| | - Sunmin Jang
- Department of Mechanical Engineering (Integrated Engineering Program), Kyung Hee University, 1732 Deogyeong-daero, Yongin, Gyeonggi, 17104, South Korea
| | - Donghyeon Yoo
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Pohang, Gyeongbuk, 37673, South Korea
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Sung Jea Park
- School of Mechanical Engineering, Korea University of Technology and Education, 1600 Chungjeol-ro, Cheonan, Chungnam, 31253, South Korea
- Advanced Technology Research Centre, Korea University of Technology and Education, 1600 Chungjeol-ro, Cheonan, Chungnam, 31253, South Korea
- Future Convergence Engineering, Korea University of Technology and Education, 1600 Chungjeol-ro, Cheonan, Chungnam, 31253, South Korea
| | - Moonwoo La
- School of Mechanical Engineering, Korea University of Technology and Education, 1600 Chungjeol-ro, Cheonan, Chungnam, 31253, South Korea
| | - Dongwhi Choi
- Department of Mechanical Engineering (Integrated Engineering Program), Kyung Hee University, 1732 Deogyeong-daero, Yongin, Gyeonggi, 17104, South Korea
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9
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Papierowska E, Beczek M, Mazur R, Szatyłowicz J, Szewińska J, Polakowski C, Ryżak M, Stańczyk T, Sochan A, Frankowska-Łukawska J, Bieganowski A. Drop impact dynamics on the hydrophobic leaf surface of an aquatic plant: a case study of Pistia stratiotes. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:5255-5272. [PMID: 37249250 DOI: 10.1093/jxb/erad203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 05/28/2023] [Indexed: 05/31/2023]
Abstract
Pistia stratiotes is an aquatic plant with a complex structure that allows it to stay afloat. It grows quickly, and in large numbers becomes an undesirable plant as an invasive species. Describing the dynamics of a water drop splash on P. stratiotes leaves can contribute to increasing knowledge of its behavior and finding alternative methods for eradicating it or using it for the benefit of the environment. The non-wettable surface of P. stratiotes presents a complex structure-simple uniseriate trichomes and also ridges and veins. We analyzed the drop impact on a leaf placed on the water surface and recorded it by high-speed cameras. Based on the recordings, quantitative and qualitative analyses were performed. After impacting the leaf, the water drop spread until it reached its maximum surface area accompanied by the ejection of early droplets in the initial stage. Thereafter, three scenarios of water behavior were observed: (i) drop receding and stabilization; (ii) drop receding and ejection of late droplets formed in the later stage as an effect of elastic deformation of the leaf; and (iii) drop breaking apart and ejection of late droplets. The results indicated that the increasing kinetic energy of the impacting drops expressed by the Weber number and the complex leaf surface have an effect on the course of the splash. The simple uniseriate trichomes of the P. stratiotes leaf and the high energy of the falling drops were responsible for the formation and characteristics of the early droplets. The presence of ridges and veins and the leaf's mechanical response had an impact on the occurrence of late droplets.
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Affiliation(s)
- Ewa Papierowska
- Water Centre, Institute of Environmental Engineering, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland
| | - Michał Beczek
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland
| | - Rafał Mazur
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland
| | - Jan Szatyłowicz
- Department of Environmental Management, Institute of Environmental Engineering, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland
| | - Joanna Szewińska
- Department of Biochemistry and Microbiology, Institute of Biology, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland
| | - Cezary Polakowski
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland
| | - Magdalena Ryżak
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland
| | - Tomasz Stańczyk
- Department of Hydrology, Meteorology and Water Management Institute of Environmental Engineering, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland
| | - Agata Sochan
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland
| | - Justyna Frankowska-Łukawska
- Department of Botany, Institute of Biology, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland
| | - Andrzej Bieganowski
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland
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10
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Ferrari M, Cirisano F. Wetting Properties of Simulated and Commercial Contaminants on High Transmittance Superhydrophobic Coating. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2541. [PMID: 37764570 PMCID: PMC10534532 DOI: 10.3390/nano13182541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/31/2023] [Accepted: 09/07/2023] [Indexed: 09/29/2023]
Abstract
The large and necessary diffusion of huge solar plants in extra urban areas implies the adoption of maintenance strategies especially where human intervention would require high costs and logistic problems. Animal dejections like bird droppings and agricultural sprays are environmental agents able to significantly decrease light absorption and, in some cases, cause serious damage to the electric conversion systems in a photovoltaic panel. In this work, the performance of a superhydrophobic (SH) coating in terms of durable self-cleaning properties and transparency has been studied in the presence of commercial and simulated contaminants on glass reference and solar panel surfaces. Wettability studies have been carried out both in static and dynamic conditions in order to compare the compositional effect of commercial liquids used as fertilizers or pesticides and molecules like pancreatin as model substances simulating bird droppings. From these studies, it can be observed that the superhydrophobic coating, independently from the surface where it is applied, is able to repel water and substances used such as fertilizers or pesticides and substances simulating bird droppings, maintaining its properties and transparency. This kind of approach can provide information to design suitable spray formulations without the above-mentioned drawbacks to be used in natural environment areas and agrosolar plants.
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Affiliation(s)
- Michele Ferrari
- Correspondence: (M.F.); (F.C.); Tel.: +39-0106475723 (M.F.); +39-0106475707 (F.C.); Fax: +39-0106475700 (M.F. & F.C.)
| | - Francesca Cirisano
- Correspondence: (M.F.); (F.C.); Tel.: +39-0106475723 (M.F.); +39-0106475707 (F.C.); Fax: +39-0106475700 (M.F. & F.C.)
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11
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Li R, Zhu P, Xu Y, Lu H, Rong J. Molecular Dynamics Simulation of Droplet Impact on a Hydrophobic 3D Elastic Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023. [PMID: 37450274 DOI: 10.1021/acs.langmuir.3c01519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/18/2023]
Abstract
The phenomenon of droplets impacting elastic surfaces is common in nature and in many engineering applications. It has been shown that droplet impact on an elastic surface drastically reduces droplet contact time and hinders droplet spreading. However, most of the current studies are based on experiments, and the analysis of the influence mechanism of the elastic substrate on the dynamic behavior of droplets is not complete. In addition, the simulations of droplet impact on elastic substrates are mainly focused on 2D elastic films or vibrating rigid substrates, ignoring the effect of 3D elastic substrate deformation on the droplet dynamic behavior. Therefore, in this paper, we propose to model the droplet impact on a 3D hydrophobic elastic substrate using the molecular dynamics method. We find that droplet pancake rebound can substantially reduce the droplet contact time. Moreover, we record the conditions required for the pancake rebound of the droplet. Furthermore, we investigated the effects of the elastic modulus of the substrate and the initial velocity of the droplet on the droplet contact time, contact area, and spreading factor. This study further elucidates the influence mechanism of the elastic substrate on the dynamic behavior of the droplet and provides theoretical guidance for regulating the dynamic behavior of the droplet in related fields.
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Affiliation(s)
- Rao Li
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 10081, PR China
| | - Pengzhe Zhu
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 10081, PR China
| | - Yimeng Xu
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 10081, PR China
| | - Hongsheng Lu
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 10081, PR China
| | - Jiacheng Rong
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 10081, PR China
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12
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Li C, Wang P, Zhang D. Design and Strengthening of Superhydrophobic Coatings: The Influence of Intermediate Layers. ACS APPLIED MATERIALS & INTERFACES 2023; 15:23875-23887. [PMID: 36977354 DOI: 10.1021/acsami.2c22776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The employment of intermediate layer technology to improve the mechanical stability of superhydrophobic coatings (SHCs) is an acknowledged tool, but the mechanism by which intermediate layers, especially different ones, affect superhydrophobic composite coatings is not clear. In this work, a series of SHCs based on the strengthening of the intermediate layer were fabricated by employing polymers with different elastic moduli such as polydimethylsiloxane (PDMS), polyurethane (PU), epoxy (EP) resin, as well as graphite/SiO2 hydrophobic components. Following that, the effect of different elastic modulus polymers as an intermediate layer on the durability of SHCs was investigated. From the perspective of elastic buffering, the strengthening mechanism of elastic polymer-based SHCs was clarified. Furthermore, from the perspective of self-lubrication, the wear resistance mechanism of self-lubricating hydrophobic components in the SHCs was elucidated. Also, the prepared coatings exhibited excellent acid and alkali resistance, self-cleaning, anti-stain, and corrosion resistance. This work confirms that low-elastic-modulus polymers can also play the role of buffering external impact energy by elastic deformation even as an intermediate layer, and provides theoretical guidance for the development of SHCs with robustness.
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Affiliation(s)
- Changyang Li
- Key Laboratory of Marine Environmental Corrosion and Bio-fouling, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
- University of Chinese Academy of Sciences, Beijing 100039, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
- Open Studio for Marine Corrosion and Protection, Pilot National Laboratory for Marine Science and Technology (Qingdao), 168 Wenhai Middle Road, Qingdao 266237, China
| | - Peng Wang
- Key Laboratory of Marine Environmental Corrosion and Bio-fouling, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
- Open Studio for Marine Corrosion and Protection, Pilot National Laboratory for Marine Science and Technology (Qingdao), 168 Wenhai Middle Road, Qingdao 266237, China
| | - Dun Zhang
- Key Laboratory of Marine Environmental Corrosion and Bio-fouling, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
- Open Studio for Marine Corrosion and Protection, Pilot National Laboratory for Marine Science and Technology (Qingdao), 168 Wenhai Middle Road, Qingdao 266237, China
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13
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Jiang S, Diao Y, Yang H. Recent advances of bio-inspired anti-icing surfaces. Adv Colloid Interface Sci 2022; 308:102756. [PMID: 36007284 DOI: 10.1016/j.cis.2022.102756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/16/2022] [Accepted: 08/11/2022] [Indexed: 11/25/2022]
Abstract
The need for improved anti-icing surfaces is the demand of the time and closely related to many important aspects of our lives as surface icing threatens not only industrial production but also human safety. Freezing on a cold surface is usually a heterogeneous nucleation process induced by the substrate. Creating an anti-icing surface is mainly achieved by changing surface morphology and chemistry to regulate the interaction between the surface and the water/ice to inhibit freezing on the surface. In this paper, recent research progress in the creation of biomimetic anti-icing surfaces is reviewed. Firstly, basic strategies of bionic anti-icing are introduced, and then bionic anti-icing surface strategies are reviewed according to four aspects: the process of ice formation, including condensate self-removing, inhibiting ice nucleation, reducing ice adhesion, and melting accumulated ice on the surface. The remaining challenges and the direction of future development of biomimetic anti-icing surfaces are also discussed.
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Affiliation(s)
- Shanshan Jiang
- School of Materials Science and Engineering, Zhengzhou University, 450001 Zhengzhou, Henan, China
| | - Yunhe Diao
- School of Materials Science and Engineering, Zhengzhou University, 450001 Zhengzhou, Henan, China
| | - Huige Yang
- School of Materials Science and Engineering, Zhengzhou University, 450001 Zhengzhou, Henan, China.
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14
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Ding S, Dai Z, Chen G, Lei M, Song Q, Gao Y, Zhou Y, Zhou B. Regulation of Droplet Rebound Behavior with Contact Time Control on a Flexible and Superhydrophobic Film. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:2942-2953. [PMID: 35200028 DOI: 10.1021/acs.langmuir.1c03429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Rapid droplet detachment from the surface in a "pancake rebound" has recently attracted abundant interest owing to the contact time control for applications in anti-icing and self-cleaning. Even though the pancake rebound on rigid substrates has been realized, the establishment of artificial structures on a flexible counterpart with droplet impact behavior studies has rarely been reported. Here, we introduced a facile approach to fabricating a flexible superhydrophobic film decorated with tunable hierarchical micro/nanostructures for water repellency. With the appropriately optimized architecture, the pancake rebound with reduced contact time can be realized when reaching a specific Weber number on the microcones. We also observed that the pancake rebound on microcilia could be realized by regulating the energy-transfer process on the flexible film during the droplet impact. A tightly stretched and suspended film can serve as the "spring" to store the elastic energy transferred from the kinetic energy of the penetrated droplet while converting back to kinetic energy during the emptying process with a reduced contact time of 5.2 ms. With the preserved water repellency on diverse curvatures, the study raises a new avenue to realize superhydrophobic surfaces and rapid droplet detachment with the potential for a broader spectrum toward practical scenarios in our daily life.
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Affiliation(s)
| | | | | | | | - Qi Song
- Shenzhen Shineway Technology Corporation, Shenzhen 518000, Guangdong, China
| | - Yibo Gao
- Shenzhen Shineway Technology Corporation, Shenzhen 518000, Guangdong, China
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15
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Qian C, Zhou F, Wang T, Li Q, Hu D, Chen X, Wang Z. Pancake Jumping of Sessile Droplets. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2103834. [PMID: 35032105 PMCID: PMC8895051 DOI: 10.1002/advs.202103834] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 12/06/2021] [Indexed: 05/26/2023]
Abstract
Rapid droplet shedding from surfaces is fundamentally interesting and important in numerous applications such as anti-icing, anti-fouling, dropwise condensation, and electricity generation. Recent efforts have demonstrated the complete rebound or pancake bouncing of impinging droplets by tuning the physicochemical properties of surfaces and applying external control, however, enabling sessile droplets to jump off surfaces in a bottom-to-up manner is challenging. Here, the rapid jumping of sessile droplets, even cold droplets, in a pancake shape is reported by engineering superhydrophobic magnetically responsive blades arrays. This largely unexplored droplet behavior, termed as pancake jumping, exhibits many advantages such as short interaction time and high energy conversion efficiency. The critical conditions for the occurrence of this new phenomenon are also identified. This work provides a new toolkit for the attainment of well-controlled and active steering of both sessile and impacting droplets for a wide range of applications.
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Affiliation(s)
- Chenlu Qian
- MIIT Key Laboratory of Thermal Control of Electronic EquipmentSchool of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing210094China
| | - Fan Zhou
- MIIT Key Laboratory of Thermal Control of Electronic EquipmentSchool of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing210094China
| | - Ting Wang
- Department of Mechanical EngineeringCity University of Hong KongHong Kong999077China
| | - Qiang Li
- MIIT Key Laboratory of Thermal Control of Electronic EquipmentSchool of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing210094China
| | - Dinghua Hu
- MIIT Key Laboratory of Thermal Control of Electronic EquipmentSchool of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing210094China
| | - Xuemei Chen
- MIIT Key Laboratory of Thermal Control of Electronic EquipmentSchool of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing210094China
| | - Zuankai Wang
- Department of Mechanical EngineeringCity University of Hong KongHong Kong999077China
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16
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Roth-Nebelsick A, Konrad W, Ebner M, Miranda T, Thielen S, Nebelsick JH. When rain collides with plants-patterns and forces of drop impact and how leaves respond to them. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:1155-1175. [PMID: 35038724 DOI: 10.1093/jxb/erac004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 01/07/2022] [Indexed: 06/14/2023]
Abstract
Raindrop impact on leaves is a common event which is of relevance for numerous processes, including the dispersal of pathogens and propagules, leaf wax erosion, gas exchange, leaf water absorption, and interception and storage of rainwater by canopies. The process of drop impact is complex, and its outcome depends on many influential factors. The wettability of plants has been recognized as an important parameter which is itself complex and difficult to determine for leaf surfaces. Other important parameters include leaf inclination angle and the ability of leaves to respond elastically to drop impact. Different elastic motions are initiated by drop impact, including local deformation, flapping, torsion, and bending, as well as 'swinging' of the petiole. These elastic responses, which occur on different time scales, can affect drop impact directly or indirectly, by changing the leaf inclination. An important feature of drop impact is splashing, meaning the fragmentation of the drop with ejection of satellite droplets. This process is promoted by the kinetic energy of the drop and leaf traits. For instance, a dense trichome cover can suppress splashing. Basic drop impact patterns are presented and discussed for a number of different leaf types, as well as some exemplary mosses.
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Affiliation(s)
- Anita Roth-Nebelsick
- State Museum of Natural History Stuttgart, Rosenstein 1, D-70191 Stuttgart, Germany
| | - Wilfried Konrad
- University of Tübingen, Department of Geosciences, Schnarrenbergstr. 94-96, D-72076 Tübingen, Germany
- Technical University of Dresden, Institute of Botany, Zellescher Weg 20b, D-01217 Dresden, Germany
| | - Martin Ebner
- University of Tübingen, Department of Geosciences, Schnarrenbergstr. 94-96, D-72076 Tübingen, Germany
| | - Tatiana Miranda
- Senckenberg Centre for Human Evolution and Palaeoenvironment at the University of Tübingen, Hölderlinstr. 12, D-72074 Tübingen, Germany
| | - Sonja Thielen
- University of Tübingen, Department of Geosciences, Schnarrenbergstr. 94-96, D-72076 Tübingen, Germany
| | - James H Nebelsick
- University of Tübingen, Department of Geosciences, Schnarrenbergstr. 94-96, D-72076 Tübingen, Germany
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17
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He Z, Jamil MI, Li T, Zhang Q. Enhanced Surface Icephobicity on an Elastic Substrate. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:18-35. [PMID: 34919404 DOI: 10.1021/acs.langmuir.1c02168] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Ice accumulation on exposed surfaces is unavoidable as time elapses and the temperature decreases sufficiently. To mitigate icing problems, various types of icephobic substrates have been rationally designed, including superhydrophobic substrates (SHSs), aqueous lubricating layers, organic lubricating layers, organogels, polyelectrolyte brush layers, electrolyte-based hydrogels, elastic substrates, and multicrack initiator-promoted surfaces. Among these surfaces, elastic substrates show excellent enhanced surface icephobicity during dynamic processes (i.e., water-impacting and de-icing tests). Herein, we summarize recent progress in elastic icephobic substrates and discuss the reasons that surface icephobicity can be enhanced on elastic substrates in terms of enhanced water repellency and further lowering the ice adhesion strength. For enhanced water repellency, we focus on reducing the contact time of water impacting such that water droplets can be easily shed from an elastic substrate before ice occurs. Reducing the contact time of water impacting various substrates (i.e., micro/nanostructured rigid SHSs, macrotextured rigid SHSs, and elastic SHSs) is discussed, followed by exploring their mechanisms. We argue that the ice adhesion strength can be further lowered on an elastic substrate by rationally tuning the elastic modulus and surface textures (i.e., surface textured and hollow subsurface textured) and combining elastic substrate with other passive anti-icing strategies (or functioning passive icephobic substrates with an electrothermal or photothermal stimulus). In short, the introduction of an elastic substrate into a passive or active icephobicity surface opens an avenue toward designing a versatile icephobic surface, providing great potential for outdoor anti-icing applications.
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Affiliation(s)
- Zhiwei He
- Center for Advanced Optoelectronic Materials, Anti-Icing Materials (AIM) Laboratory, College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Muhammad Imran Jamil
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027, China
| | - Tong Li
- Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Qinghua Zhang
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027, China
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18
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Löffler RJG, Hanczyc MM, Gorecki J. A camphene-camphor-polymer composite material for the production of superhydrophobic absorbent microporous foams. Sci Rep 2022; 12:243. [PMID: 34997122 PMCID: PMC8741767 DOI: 10.1038/s41598-021-04240-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 12/17/2021] [Indexed: 11/10/2022] Open
Abstract
In a recently published paper (doi.org/10.3390/molecules26113116) on self-propelled motion of objects on the water surface, we described a novel surface-active plastic material obtained by dissolution of camphor and polypropylene in camphene at 250 \documentclass[12pt]{minimal}
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\begin{document}$$^\circ$$\end{document}∘C. The material has wax-like mechanical properties, can be easily formed to any moldable shape, and allows for longer and more stable self-propelled motion if compared with pure camphor or pure camphene or of a camphene-camphor wax. Here we use scanning electron microscopy to visualize and characterize the microporous structure of the solid polypropylene foam formed in the plastic for different polypropylene contents. The topology of foams remaining in the material after camphor and camphene molecules have been removed through evaporation or dissolution is similar to polypropylene foams obtained using thermally-induced phase separation. We show that the foams have a superhydrophobic surface but strongly absorb non-polar liquids, and suggest an array of potential scientific and industrial applications.
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Affiliation(s)
- Richard J G Löffler
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Mazowieckie, Poland.,Laboratory for Artificial Biology, Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Polo Scientifico e Tecnologico Fabio Ferrari, Polo B, Via Sommarive 9, Povo, 38123, Trentino Alto-Adige, Italy
| | - Martin M Hanczyc
- Laboratory for Artificial Biology, Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Polo Scientifico e Tecnologico Fabio Ferrari, Polo B, Via Sommarive 9, Povo, 38123, Trentino Alto-Adige, Italy.,Farris Engineering Center, Chemical and Biological Engineering, University of New Mexico, Albuquerque, NM, 87106, USA
| | - Jerzy Gorecki
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Mazowieckie, Poland.
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19
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Sun Y, Zheng Y, Song L, Sun P, Zhao M, Zhou Y, Tee CATH. Elasticity and damping ratio measurement of droplets on super-hydrophobic surfaces. ROYAL SOCIETY OPEN SCIENCE 2022; 9:211632. [PMID: 35242354 PMCID: PMC8753166 DOI: 10.1098/rsos.211632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 12/20/2021] [Indexed: 06/14/2023]
Abstract
The measurement of the droplets' elasticity is vitally important in microfluidic and ink-jet printing. It refers to the ability of the droplet to restore its original shape and strong robustness. This study investigated a novel method to measure elasticity. The plate coated with super-hydrophobic layers pressed on a droplet and the elastic force was recorded by an electronic balance. Meanwhile, a mathematical model was constructed to calculate the changes of the droplet area under the force. The measurement showed that external work mainly converts into surface energy and the damping ratio increases from 0.068 to 0.261 with the increase of mass fraction from 0 to 80 wt%. It also indicates that the novel method can accurately and efficiently measure the elasticity of droplets.
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Affiliation(s)
- Yukai Sun
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin, People’s Republic of China
| | - Yelong Zheng
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin, People’s Republic of China
| | - Le Song
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin, People’s Republic of China
| | - Peiyuan Sun
- Dongying Vocational Institute, Dongying, People’s Republic of China
| | - Meirong Zhao
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin, People’s Republic of China
| | - Yixiong Zhou
- Department of Ophthalmology, Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China
| | - Clarence Augustine TH Tee
- Department of Electrical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia
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20
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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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21
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Konrad W, Roth-Nebelsick A, Kessel B, Miranda T, Ebner M, Schott R, Nebelsick JH. The impact of raindrops on Salvinia molesta leaves: effects of trichomes and elasticity. J R Soc Interface 2021; 18:20210676. [PMID: 34905964 DOI: 10.1098/rsif.2021.0676] [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] [Indexed: 11/12/2022] Open
Abstract
The floating leaves of the aquatic fern Salvinia molesta are covered by superhydrophobic hairs (=trichomes) which are shaped like egg-beaters. These trichomes cause high water repellency and stable unwettability if the leaf is immersed. Whereas S. molesta hairs are technically interesting, there remains also the question concerning their biological relevance. S. molesta has its origin in Brazil within a region exposed to intense rainfall which easily penetrates the trichome cover. In this study, drop impact on leaves of S. molesta were analysed using a high-speed camera. The largest portion of the kinetic energy of a rain drop is absorbed by elastic responses of the trichomes and the leaf. Although rain water is mostly repelled, it turned out that the trichomes hamper swift shedding of rain water and some residual water can remain below the 'egg-beaters'. Drops rolling over the trichomes can, however, 'suck up' water trapped beneath the egg-beaters because the energetic state of a drop on top of the trichomes is-on account of the superhydrophobicity of the hairs-much more favourable. The trichomes may therefore be beneficial during intense rainfall, because they absorb some kinetic energy and keep the leaf base mostly free from water.
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Affiliation(s)
- Wilfried Konrad
- Department of Geosciences, University of Tübingen, Schnarrenbergstraße 94-96, Tübingen 72076, Germany.,Institute of Botany, Technical University of Dresden, Zellescher Weg 20b, Dresden 01217, Germany
| | - Anita Roth-Nebelsick
- State Museum of Natural History Stuttgart, Rosenstein 1, Stuttgart 70191, Germany
| | - Benjamin Kessel
- Department of Geosciences, University of Tübingen, Schnarrenbergstraße 94-96, Tübingen 72076, Germany
| | - Tatiana Miranda
- Department of Geosciences, University of Tübingen, Schnarrenbergstraße 94-96, Tübingen 72076, Germany
| | - Martin Ebner
- Department of Geosciences, University of Tübingen, Schnarrenbergstraße 94-96, Tübingen 72076, Germany
| | - Rena Schott
- State Museum of Natural History Stuttgart, Rosenstein 1, Stuttgart 70191, Germany
| | - James H Nebelsick
- Department of Geosciences, University of Tübingen, Schnarrenbergstraße 94-96, Tübingen 72076, Germany
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22
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Du J, Wang X, Li Y, Min Q. Maximum spreading of liquid droplets impact on concentric ring-textured surfaces: Theoretical analysis and numerical simulation. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.127647] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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23
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Hu S, Cao X, Reddyhoff T, Shi X, Peng Z, deMello AJ, Dini D. Flexibility-Patterned Liquid-Repelling Surfaces. ACS APPLIED MATERIALS & INTERFACES 2021; 13:29092-29100. [PMID: 34078079 DOI: 10.1021/acsami.1c05243] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Droplets impacting solid surfaces is ubiquitous in nature and of practical importance in numerous industrial applications. For liquid-repelling applications, rigidity-based asymmetric redistribution and flexibility-based structural oscillation strategies have been proven on artificial surfaces; however, these are limited by strict impacting positioning. Here, we show that the gap between these two strategies can be bridged by a flexibility-patterned design similar to a trampoline park. Such a flexibility-patterned design is realized by three-dimensional projection micro-stereolithography and is shown to enhance liquid repellency in terms of droplet impalement resistance and contact time reduction. This is the first demonstration of the synergistic effect obtained by a hybrid solution that exploits asymmetric redistribution and structural oscillation in liquid-repelling applications, paving the rigidity-flexibility cooperative way of wettability tuning. Also, the flexibility-patterned surface is applied to accelerate liquid evaporation.
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Affiliation(s)
- Songtao Hu
- State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiaobao Cao
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich 8093, Switzerland
| | - Tom Reddyhoff
- Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, U.K
| | - Xi Shi
- State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhike Peng
- State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Andrew J deMello
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich 8093, Switzerland
| | - Daniele Dini
- Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, U.K
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24
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Du J, Wang X, Li Y, Min Q, Wu X. Analytical Consideration for the Maximum Spreading Factor of Liquid Droplet Impact on a Smooth Solid Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:7582-7590. [PMID: 34114824 DOI: 10.1021/acs.langmuir.1c01076] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Based on the energy conservation approach, this study develops a universal model to predict the maximum spreading factor of liquid droplet impact on a smooth solid surface. Validated with the present simulations and experiments in the literature, this model effectively overcomes the limitation of previous models in the viscous regime and greatly reduces the computing errors from over 30% to below 6%. It is demonstrated that the underestimated maximum spreading factor by previous models results from the overestimation of viscous dissipation. By replacing the conventional model of spreading time, tm = 8D0/3U0, with a more precise one, tm = 1.47τiWe-0.44, the formulation to compute the viscous dissipation of entire spreading is improved. Finally, we examine the applicability of present model in the capillary regime and good performance is also shown.
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Affiliation(s)
- Jiayu Du
- Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
| | - Xiong Wang
- Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
| | - Yanzhi Li
- Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
| | - Qi Min
- Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
| | - Xinxin Wu
- Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
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25
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Ji T, Pan Y, Shao Y, He B, Wen B. Lateral Drop Rebound on a Hydrophobic and Chemically Heterogeneous Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:6905-6914. [PMID: 34060835 DOI: 10.1021/acs.langmuir.1c00242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In this paper, the process of a drop rebounding from a hydrophobic and chemically heterogeneous surface is investigated using the multiphase lattice Boltzmann method. The bounce behavior of drops is dependent on the degree of hydrophobicity and heterogeneity of the surface. When the surface is homogeneous, the drop rebounds vertically and the height increases with the enhancement of the surface hydrophobicity. For the heterogeneous surface with two different hydrophobic parts, the drop rebounds laterally toward the lower hydrophobic side. Because the high hydrophobic side exerts the stronger unbalanced Young's force on the contact line compared with the low hydrophobic side, the difference of the forces results in the asymmetrical rebound. A phase diagram displays the rebound numbers of a drop impacting on the various chemically homogeneous and heterogeneous surfaces. A simply quantitative estimation is made to predict the rebound heights and flying times through the contact angles of the surface. This work promotes the understanding of the rebound mechanism of a drop impacting on a chemically heterogeneous surface and provides a guiding strategy for the precise control of the lateral behavior of rebounding drops by hydrophobic and heterogeneous surfaces.
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Affiliation(s)
- Tingting Ji
- Guangxi Key Lab of Multi-Source Information Mining & Security, Guangxi Normal University, Guilin 541004, China
- College of Computer Science and Information Engineering, Guangxi Normal University, Guilin 541004, China
| | - Yongcai Pan
- Guangxi Key Lab of Multi-Source Information Mining & Security, Guangxi Normal University, Guilin 541004, China
- College of Computer Science and Information Engineering, Guangxi Normal University, Guilin 541004, China
| | - Yufu Shao
- Guangxi Key Lab of Multi-Source Information Mining & Security, Guangxi Normal University, Guilin 541004, China
- College of Computer Science and Information Engineering, Guangxi Normal University, Guilin 541004, China
| | - Bing He
- Guangxi Key Lab of Multi-Source Information Mining & Security, Guangxi Normal University, Guilin 541004, China
- College of Computer Science and Information Engineering, Guangxi Normal University, Guilin 541004, China
| | - Binghai Wen
- Guangxi Key Lab of Multi-Source Information Mining & Security, Guangxi Normal University, Guilin 541004, China
- College of Computer Science and Information Engineering, Guangxi Normal University, Guilin 541004, China
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Mousa MH, Günay AA, Orejon D, Khodakarami S, Nawaz K, Miljkovic N. Gas-Phase Temperature Mapping of Evaporating Microdroplets. ACS APPLIED MATERIALS & INTERFACES 2021; 13:15925-15938. [PMID: 33755427 DOI: 10.1021/acsami.1c02790] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Evaporation is a ubiquitous and complex phenomenon of importance to many natural and industrial systems. Evaporation occurs when molecules near the free interface overcome intermolecular attractions with the bulk liquid. As molecules escape the liquid phase, heat is removed, causing evaporative cooling. The influence of evaporative cooling on inducing a temperature difference with the surrounding atmosphere as well as within the liquid is poorly understood. Here, we develop a technique to overcome past difficulties encountered during the study of heterogeneous droplet evaporation by coupling a piezo-driven droplet generation mechanism to a controlled micro-thermocouple to probe microdroplet evaporation. The technique allowed us to probe the gas-phase temperature distribution using a micro-thermocouple (50 μm) in the vicinity of the liquid-vapor interface with high spatial (±10 μm) and temporal (±100 ms) resolution. We experimentally map the temperature gradient formed surrounding sessile water droplets having varying curvature dictated by the apparent advancing contact angle (100° ≲ θ ≲ 165°). The experiments were carried out at temperatures below and above ambient for a range of fixed droplet radii (130 μm ≲ R ≲ 330 μm). Our results provide a primary validation of the centuries-old theoretical framework underpinning heterogeneous droplet evaporation mediated by the working fluid, substrate, and gas thermophysical properties, droplet apparent contact angle, and droplet size. We show that microscale droplets residing on low-thermal-conductivity substrates such as glass absorb up to 8× more heat from the surrounding gas compared to droplets residing on high-thermal-conductivity substrates such as copper. Our work not only develops an experimental understanding of the heat transfer mechanisms governing droplet evaporation but also presents a powerful platform for the study and characterization of liquid-vapor transport at curved interfaces wetting and nonwetting advanced functional surfaces.
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Affiliation(s)
- Mohamed H Mousa
- Department of Mechanical Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States
| | - Ahmet Alperen Günay
- Department of Mechanical Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States
| | - Daniel Orejon
- Department of Mechanical Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States
- Institute for Multiscale Thermofluids, School of Engineering, The University of Edinburgh, Edinburgh EH9 3FD, Scotland, U.K
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Siavash Khodakarami
- Department of Mechanical Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States
| | - Kashif Nawaz
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Nenad Miljkovic
- Department of Mechanical Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States
- International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, United States
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Kabi P, Razdan V, Roy D, Bansal L, Sahoo S, Mukherjee R, Chaudhuri S, Basu S. Evaporation-induced alterations in oscillation and flow characteristics of a sessile droplet on a rose-mimetic surface. SOFT MATTER 2021; 17:1487-1496. [PMID: 33459336 DOI: 10.1039/d0sm02106g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Strategic control of evaporation dynamics can help control oscillation modes and internal flow field in an oscillating sessile droplet. This article presents the study of an oscillating droplet on a bio-inspired "sticky" surface to better understand the nexus between the modes of evaporation and oscillation. Oscillation in droplets can be characterized by the number of nodes forming on the surface and is referred to as the mode of oscillation. An evaporating sessile droplet under constant periodic perturbation naturally self-tunes between different oscillation modes depending on its geometry. The droplet geometry evolves according to the mode of evaporation controlled by substrate topography. We use a bio-inspired, rose patterned, "sticky" hydrophobic substrate to perpetually pin the contact line of the droplet in order to hence achieve a single mode of evaporation for most of the droplet's lifetime. This allows the prediction of experimentally observed oscillation mode transitions at different excitation frequencies. We present simple scaling arguments to predict the velocity of the internal flow induced by the oscillation. The findings are beneficial to applications which seek to tailor energy and mass transfer rates across liquid droplets by using bio-inspired surfaces.
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Affiliation(s)
- Prasenjit Kabi
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India.
| | - Vishank Razdan
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India.
| | - Durbar Roy
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India.
| | - Lalit Bansal
- School of Mechanical Engineering, Vellore Institute of Technology, Vellore, India
| | - Sumita Sahoo
- Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Rabibrata Mukherjee
- Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India
| | | | - Saptarshi Basu
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India.
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Parihar V, Chakraborty S, Das S, Chakraborty S, DasGupta S. Role of anisotropic pinning and liquid properties during partial rebound of droplets on unidirectionally structured hydrophobic surfaces. Chem Eng Sci 2021. [DOI: 10.1016/j.ces.2020.116197] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Variability of Leaf Wetting and Water Storage Capacity of Branches of 12 Deciduous Tree Species. FORESTS 2020. [DOI: 10.3390/f11111158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Leaf surface wettability and factors which determine it are key in determining the water storage capacity of tree crowns and thus the interception of entire stands. Leaf wettability, expressed as the droplet inclination angle, and the surface free energy largely depend not only on the chemical composition of the leaves but also on their texture. The study concerns 12 species of trees common in Central Europe. The content of epicuticular waxes was determined in the leaves, and values ranging from 9.145 [µg/cm2] for horse chestnut (Aesculus hippocastanum L.) to 71.759 [µg/cm2] for birch (Betula pendula Roth.) were obtained. Each additional µg/cm2 increases the canopy water storage capacity by 0.067 g g−1. For all species, the inclination angles of water, diiodomethane and glycerin droplets to the leaf surface were measured and the surface free energy was calculated. It is shown that it is the wax content and the species that constitute independent predictors of water storage capacity. These factors explain the 95.56% effect on the value of canopy water storage capacity. The remaining 4.44% indicate non-species-related individual features or the ability to mitigate pollutants as well as possible environmental factors. Wax analyzed separately from other factors causes a slight increase (by 0.067 g/g) of S. Nevertheless, the influence of the surface condition as a result of species-related variability is decisive for the value of the canopy water storage capacity.
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Droplet Impact on the Cold Elastic Superhydrophobic Membrane with Low Ice Adhesion. COATINGS 2020. [DOI: 10.3390/coatings10100964] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The elastic membranes with different surface stiffness were fabricated via spin-coating followed by the laser ablation. The as-fabricated elastic membrane exhibited superhydrophobicity with a rough microstructure. The droplet impacting experiment on the cold elastic superhydrophobic membrane was conducted, and the influence of surface stiffness and impacting speed on the droplet impacting process were investigated. It was found that the elastic superhydrophobic membrane exhibits a robust anti-icing performance compared with the elastic hydrophobic membrane. A lower surface stiffness corresponds to a larger deformation degree of the elastic membrane and to a smaller maximum droplet spreading diameter. Moreover, the contact time decreases with the increase of impacting speed as for the same stiffness of the cold elastic superhydrophobic membrane. The underlying mechanism of the cold elastic membrane with low ice adhesion may be due to the face that the deformation of the superhydrophobic membrane provides an elastic force for the droplet to detach from the surface and thus reduce the heat transfer between the droplet and the surface.
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Hu S, Cao X, Reddyhoff T, Puhan D, Vladescu SC, Wang J, Shi X, Peng Z, deMello AJ, Dini D. Liquid repellency enhancement through flexible microstructures. SCIENCE ADVANCES 2020; 6:eaba9721. [PMID: 32923610 PMCID: PMC7457340 DOI: 10.1126/sciadv.aba9721] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 06/18/2020] [Indexed: 05/29/2023]
Abstract
Artificial liquid-repellent surfaces have attracted substantial scientific and industrial attention with a focus on creating functional topological features; however, the role of the underlying structures has been overlooked. Recent developments in micro-nanofabrication allow us now to construct a skin-muscle type system combining interfacial liquid repellence atop a mechanically functional structure. Specifically, we design surfaces comprising bioinspired, mushroom-like repelling heads and spring-like flexible supports, which are realized by three-dimensional direct laser lithography. The flexible supports elevate liquid repellency by resisting droplet impalement and reducing contact time. This, previously unknown, use of spring-like flexible supports to enhance liquid repellency provides an excellent level of control over droplet manipulation. Moreover, this extends repellent microstructure research from statics to dynamics and is envisioned to yield functionalities and possibilities by linking functional surfaces and mechanical metamaterials.
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Affiliation(s)
- Songtao Hu
- State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiaobao Cao
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich 8093, Switzerland
| | - Tom Reddyhoff
- Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, UK
| | - Debashis Puhan
- Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, UK
| | | | - Jing Wang
- Institute of Environmental Engineering, ETH Zurich, Zurich 8093, Switzerland
- Laboratory for Advanced Analytical Technologies, Empa, Dübendorf 8600, Switzerland
| | - Xi Shi
- State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhike Peng
- State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Andrew J. deMello
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich 8093, Switzerland
| | - Daniele Dini
- Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, UK
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Abstract
Rainfall on biological superhydrophobic surfaces is ubiquitous in nature. Previous studies in a laboratory setting have focused only on low-speed impacts, which can be quite different from rain conditions in nature. In this study, we reported unexpected and interesting shock-like patterns when a drop impacts biological surfaces at high speeds. These shock-like waves trigger sudden drop fragmentation into smaller satellite droplets and lead to a more than twofold decrease in contact time. Our findings may elucidate biological advantages (hypothermia risk reduction for birds, flight stability for insects, spore dispersal on plants) of superhydrophobic surfaces triggered by microstructures. Many biological surfaces of animals and plants (e.g., bird feathers, insect wings, plant leaves, etc.) are superhydrophobic with rough surfaces at different length scales. Previous studies have focused on a simple drop-bouncing behavior on biological surfaces with low-speed impacts. However, we observed that an impacting drop at high speeds exhibits more complicated dynamics with unexpected shock-like patterns: Hundreds of shock-like waves are formed on the spreading drop, and the drop is then abruptly fragmented along with multiple nucleating holes. Such drop dynamics result in the rapid retraction of the spreading drop and thereby a more than twofold decrease in contact time. Our results may shed light on potential biological advantages of hypothermia risk reduction for endothermic animals and spore spreading enhancement for fungi via wave-induced drop fragmentation.
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Zhang C, Wu Z, Shen C, Zheng Y, Yang L, Liu Y, Ren L. Effects of eigen and actual frequencies of soft elastic surfaces on droplet rebound from stationary flexible feather vanes. SOFT MATTER 2020; 16:5020-5031. [PMID: 32452492 DOI: 10.1039/d0sm00315h] [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
The aim of this paper is to investigate the effect of eigenfrequency and the actual frequency of the elastic surface for droplet rebound. The elastic surface used in this study is the stationary flexible feather vanes. A fluid-structure interaction (FSI) numerical model is proposed to predict the phenomenon, and later it is validated by an experiment where droplets impact the stationary flexible feather vanes. The effect of mass and stiffness of the surface is analysed. First, a suitable combination of mass and stiffness of the surface will enhance the drop rebound. Second, a small mass system with a higher eigenfrequency will decrease the minimum contact time. Finally, the actual frequencies of the elastic surface, approximately 75 Hz, can accelerate the drop rebound for all cases.
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Affiliation(s)
- Chengchun Zhang
- Key Laboratory of Engineering Bionics (Ministry of Education), Jilin University, Changchun 130022, China.
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Xiong Y, Huang H, Lu XY. Numerical study of droplet impact on a flexible substrate. Phys Rev E 2020; 101:053107. [PMID: 32575301 DOI: 10.1103/physreve.101.053107] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 05/08/2020] [Indexed: 06/11/2023]
Abstract
Droplets interacting with deformable moving boundaries is ubiquitous. The flexible boundaries may dramatically affect the hydrodynamic behavior of droplets. A numerical method for simulating droplet impact on flexible substrates is developed. The effect of flexibility is investigated. To reduce the contact time and increase the remaining upward momentum in the flexible cases, the Weber number should be larger than a critical value. Moreover, the ratio of the natural frequency of the plate to that of the droplet F_{r} should approximately equal to the reciprocal of the contact time of droplets impact on the rigid surfaces (t_{ctr}) at the same We, e.g., F_{r}≈1/t_{ctr}. Only under this circumstance would the kinetic energy convert into the surface energy of the droplet and the elastic energy of the plate simultaneously, and vice versa. Moreover, based on a double spring model, we proposed scaling laws for the maximal deflection of the plate and spreading diameter of the drop. Finally, the droplet impact under different wettability is qualitatively studied. We found that the flexibility may contribute to the droplet bouncing at a smaller contact angle.
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Affiliation(s)
- Yongfeng Xiong
- Department of Modern Mechanics, and University of Science and Technology of China, Anhui 230026, China
| | - Haibo Huang
- Department of Modern Mechanics, and University of Science and Technology of China, Anhui 230026, China
| | - Xi-Yun Lu
- Department of Modern Mechanics, and University of Science and Technology of China, Anhui 230026, China
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35
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Current Status and Future Prospects of Applying Bioinspired Superhydrophobic Materials for Conservation of Stone Artworks. COATINGS 2020. [DOI: 10.3390/coatings10040353] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The development of innovative materials is one of the most important focus areas in heritage conservation research. Eligible materials can not only protect the physical and chemical integrity of artworks but also preserve their artistic and aesthetic features. Recently, as one of the hot research topics in materials science, biomimetic superhydrophobic materials have gradually attracted the attention of conservation scientists due to their unique properties. In fact, ultra-repellent materials are particularly suitable for hydrophobization treatments on outdoor artworks. Owing to their excellent hydrophobicity, superhydrophobic materials can effectively prevent the absorption and penetration of liquid water as well as the condensation of water vapor, thus greatly relieving water-induced decay phenomena. Moreover, in the presence of liquid water, the superhydrophobic surfaces equipped with a self-cleaning property can clean the dirt and dust deposited spontaneously, thereby restoring the artistic features simultaneously. In the present paper, besides the basic principles of wetting on solid surfaces, materials, and methods reported for preparing bioinspired ultra-repellent materials, the recently proposed materials for art conservation are also introduced and critically reviewed, along with a discussion on the droplet impact and durability of the artificial superhydrophobic surfaces. Lastly, the current status and the problems encountered in practical application are also pointed out, and the focus of future research is presented as well.
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36
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Lu Y, Shen Y, Tao J, Wu Z, Chen H, Jia Z, Xu Y, Xie X. Droplet Directional Movement on the Homogeneously Structured Superhydrophobic Surface with the Gradient Non-Wettability. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:880-888. [PMID: 31939676 DOI: 10.1021/acs.langmuir.9b03411] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The surface with the gradient non-wettability intensely appeals to researchers because of its academic significance and applications for directional droplet movement. Herein, we developed a homogeneous structure superhydrophobic surface with the gradient non-wettability by a combination strategy of chemical etching and vapor diffusion modification. As a consequence, the as-prepared surface exhibits a remarkable gradient characteristic of water repellency, and the water contact angle is mainly located within the range of 162 ± 0.5 to 149 ± 0.4°. Meanwhile, the sliding angle also exhibits a corresponding change from 3 to 11°. On this basis, the gradient characteristic of non-wettability induces the distinguishing droplet adhesion on the surface, that is, from 19 μN for the most hydrophobic end to 57 μN for the opposite one. Because of the difference of the water adhesion force, droplets on the as-prepared surface can well roll alongside a specific direction (i.e., gradient direction of non-wettability). In terms of dynamic impact droplets, they can rapidly rebound off the sample surface with the short contact time of 12.8 ms, and the finally fallen droplets mainly deviate toward weaker regions because of water repellency. To analyze this phenomenon, it is found that the asymmetric mechanic behavior is mainly caused by the unbalanced retraction force between the both ends of the impact droplet. This work provides a novel strategy to construct the homogeneous structure superhydrophobic surface with the gradient non-wettability for the applications in the droplet movement control or transport.
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Affiliation(s)
- Yang Lu
- College of Materials Science and Technology , Nanjing University of Aeronautics and Astronautics , 29# Yudao Street , Nanjing 210016 , P. R. China
| | - Yizhou Shen
- College of Materials Science and Technology , Nanjing University of Aeronautics and Astronautics , 29# Yudao Street , Nanjing 210016 , P. R. China
| | - Jie Tao
- College of Materials Science and Technology , Nanjing University of Aeronautics and Astronautics , 29# Yudao Street , Nanjing 210016 , P. R. China
- Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites , 30# Puzhu South Rd. , Nanjing 210009 , P. R. China
| | - Zhengwei Wu
- College of Materials Science and Technology , Nanjing University of Aeronautics and Astronautics , 29# Yudao Street , Nanjing 210016 , P. R. China
| | - Haifeng Chen
- Department of Materials Chemistry , Qiuzhen School, Huzhou University , 759# East 2nd Road , Huzhou 313000 , P. R. China
| | - Zhenfeng Jia
- College of Materials Science and Technology , Nanjing University of Aeronautics and Astronautics , 29# Yudao Street , Nanjing 210016 , P. R. China
| | - Yangjiangshan Xu
- College of Materials Science and Technology , Nanjing University of Aeronautics and Astronautics , 29# Yudao Street , Nanjing 210016 , P. R. China
| | - Xinyu Xie
- College of Materials Science and Technology , Nanjing University of Aeronautics and Astronautics , 29# Yudao Street , Nanjing 210016 , P. R. China
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Gateman SM, Page K, Halimi I, Nascimento ARC, Savoie S, Schulz R, Moreau C, Parkin IP, Mauzeroll J. Corrosion of One-Step Superhydrophobic Stainless-Steel Thermal Spray Coatings. ACS APPLIED MATERIALS & INTERFACES 2020; 12:1523-1532. [PMID: 31820910 DOI: 10.1021/acsami.9b17836] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
As most superhydrophobic coatings are made of soft materials, the need for harder, more robust films is evident in applications where erosional degradation is of concern. The work herein describes a methodology to produce superhydrophobic stainless-steel thermal spray coatings using the high-velocity oxygen fuel technique. Due to the use of a kerosene fuel source, a carbon-rich film is formed on the surface of the thermal spray coatings, lowering the surface energy of the high-energy metallic substrates. The thermal spray process generates a hierarchical micro-/sub-micro-structure that is needed to sustain superhydrophobicity. The effect of spray parameters such as particle velocity and temperature on the coating's hydrophobicity state was explored, and a high particle velocity was shown to cause superhydrophobic characteristics. The coatings were characterized using scanning electron microscopy, profilometry, X-ray photoelectron spectroscopy, static water contact angle measurements, water droplet roll-off measurements, and water droplet bouncing tests. The corrosion behavior of the coatings was studied using potentiodynamic polarization measurements in order to correlate water repellency with corrosion resistance; however, all coatings demonstrated active corrosion without passivation. This study describes an interesting phenomenon where superhydrophobicity does not guarantee corrosion resistance and discusses alternative applications for such materials.
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Affiliation(s)
- Samantha Michelle Gateman
- Laboratory for Electrochemical Reactive Imaging and Detection of Biological Systems , McGill University , Montreal , Quebec H3A 0B8 , Canada
| | - Kristopher Page
- Materials Chemistry Department , University College London , London WC1E 6BT , United Kingdom
| | - Ilias Halimi
- Laboratory for Electrochemical Reactive Imaging and Detection of Biological Systems , McGill University , Montreal , Quebec H3A 0B8 , Canada
| | | | - Sylvio Savoie
- Institut de recherche d'Hydro-Québec , Varennes , Quebec J3X 1S1 , Canada
| | - Robert Schulz
- Institut de recherche d'Hydro-Québec , Varennes , Quebec J3X 1S1 , Canada
| | - Christian Moreau
- Thermal Spray and Multiphase Flow Laboratory , Concordia University , Montreal , Quebec H3G 1M8 , Canada
| | - Ivan P Parkin
- Materials Chemistry Department , University College London , London WC1E 6BT , United Kingdom
| | - Janine Mauzeroll
- Laboratory for Electrochemical Reactive Imaging and Detection of Biological Systems , McGill University , Montreal , Quebec H3A 0B8 , Canada
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Wu H, Jiang K, Xu Z, Yu S, Peng X, Zhang Z, Bai H, Liu A, Chai G. Theoretical and Experimental Studies on the Controllable Pancake Bouncing Behavior of Droplets. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:17000-17008. [PMID: 31786923 DOI: 10.1021/acs.langmuir.9b03153] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A droplet that impacts on a superhydrophobic surface will undergo a process of unfolding, contracting, and finally rebounding from the surface. With regards to the pancake bouncing behavior of a droplet, since the retraction process of the droplet is omitted, the contact time is greatly shortened compared to the normal type of bouncing. However, the quantitative prediction to the range of droplet pancake bouncing and the adjustment of pancake bouncing state have yet to be probed into. In this paper, we reported the controllable pancake bouncing of droplets by adjusting the size of the superhydrophobic surface with microstructures. In addition, we also discovered a dimensional effect with regards to pancake bouncing, namely, the pancake bouncing would be more likely to happen on the surfaces with large post spacing for the droplet with the larger radius. The contact time could be reduced to 2 ms by adjusting the size of the microstructures and the radius of the droplets. Based on the relationship between the droplet bouncing state and the surface microstructure size, we are able to propose reasonable dimensions for the surfaces in order to control pancake bouncing.
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Affiliation(s)
- Huaping Wu
- Key Laboratory of E&M , Zhejiang University of Technology, Ministry of Education & Zhejiang Province , Hangzhou 310014 , China
| | - Kunpeng Jiang
- Key Laboratory of E&M , Zhejiang University of Technology, Ministry of Education & Zhejiang Province , Hangzhou 310014 , China
| | - Zhenxiong Xu
- Key Laboratory of E&M , Zhejiang University of Technology, Ministry of Education & Zhejiang Province , Hangzhou 310014 , China
| | - Sihang Yu
- Key Laboratory of E&M , Zhejiang University of Technology, Ministry of Education & Zhejiang Province , Hangzhou 310014 , China
| | - Xiang Peng
- Key Laboratory of E&M , Zhejiang University of Technology, Ministry of Education & Zhejiang Province , Hangzhou 310014 , China
| | - Zheng Zhang
- Key Laboratory of E&M , Zhejiang University of Technology, Ministry of Education & Zhejiang Province , Hangzhou 310014 , China
| | - Hao Bai
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering , Zhejiang University , Hangzhou 310027 , China
| | - Aiping Liu
- Center for Optoelectronics Materials and Devices , Zhejiang Sci-Tech University , Hangzhou 310018 , China
| | - Guozhong Chai
- Key Laboratory of E&M , Zhejiang University of Technology, Ministry of Education & Zhejiang Province , Hangzhou 310014 , China
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Zheng Y, Zhang C, Wang J, Liu Y, Shen C, Yang J. Robust adhesion of droplets via heterogeneous dynamic petal effects. J Colloid Interface Sci 2019; 557:737-745. [PMID: 31563606 DOI: 10.1016/j.jcis.2019.09.070] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 09/18/2019] [Accepted: 09/19/2019] [Indexed: 12/11/2022]
Abstract
HYPOTHESIS Bionics and dynamic interface wetting intensely appeal to many research communities due to their unique practical implications. The rose petals had a highly robust dynamic water-retaining capacity under heavy precipitation. We predicted that the roses became more "hydrophilic" at higher Weber numbers. EXPERIMENTS Fresh rose petals were directly impacted by droplets, and facile artificial petal-like substrates and superhydrophobic substrates were used in the comparative analysis. The wetting dynamics of the droplet (e.g., topography, bounce dynamics, contact time, three-phase contact lines, and oscillations) were investigated when interacting with four selected target substrates. FINDINGS The present work first time investigated the dynamic wetting rule of the sticky superhydrophobic substrates (SSHS). Simulated and experimental investigations confirmed that the unique coupling synergy between the pinning effect and the inhomogeneous micropapillaes resulted in lopsided contact line velocities, which remarkably suppressed the lateral oscillation and rebounding. This may be a new strategy when designing dynamic water-repellent surfaces and open a promising avenue for emerging areas such as super-efficiency energy conversion and harvesting.
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Affiliation(s)
- Yihua Zheng
- Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022, China.
| | - Chengchun Zhang
- Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022, China; State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun, 130022, China.
| | - Jing Wang
- College of Physics, Jilin University, Changchun 130012, China.
| | - Yan Liu
- Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022, China.
| | - Chun Shen
- State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun, 130022, China.
| | - Junfeng Yang
- School of Mechanical Engineering, University of Leeds, LS2 9JT, United Kingdom.
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Song M, Hu D, Zheng X, Wang L, Yu Z, An W, Na R, Li C, Li N, Lu Z, Dong Z, Wang Y, Jiang L. Enhancing Droplet Deposition on Wired and Curved Superhydrophobic Leaves. ACS NANO 2019; 13:7966-7974. [PMID: 31268304 DOI: 10.1021/acsnano.9b02457] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Droplet deposition on superhydrophobic surfaces has been a great challenge owing to the shortness of the impact contact time. Despite recent research progress regarding flat superhydrophobic surfaces, improving deposition on ubiquitous wired and curved superhydrophobic leaves remains challenging as their surface structures promote asymmetric impacts, thereby shortening the contact times and increasing the likelihood of droplet splitting. Here, we propose a strategy to solve the deposition problems based on an analysis of the impact dynamics and a rational selection of additives. Combining the prominent extension property of flexible polymers with surface tension reduction of the surfactant, the well-chosen binary additives cooperatively solve retention and coverage problems by limiting the fragment and enhancing local pinning and wetting processes at a very low usage. This work advances the understanding of droplet deposition by rationally selecting additives based on the impact dynamics, which is believed to be useful in a variety of spraying, coating, and printing applications.
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Affiliation(s)
- Meirong Song
- College of Science , Henan Agricultural University , Zhengzhou , Henan 450002 , P.R. China
| | - Duan Hu
- College of Science , Henan Agricultural University , Zhengzhou , Henan 450002 , P.R. China
| | - Xianfu Zheng
- College of Science , Henan Agricultural University , Zhengzhou , Henan 450002 , P.R. China
| | - Lixia Wang
- College of Science , Henan Agricultural University , Zhengzhou , Henan 450002 , P.R. China
| | - Zhilun Yu
- College of Science , Henan Agricultural University , Zhengzhou , Henan 450002 , P.R. China
| | - Wankai An
- College of Science , Henan Agricultural University , Zhengzhou , Henan 450002 , P.R. China
| | - Risong Na
- College of Science , Henan Agricultural University , Zhengzhou , Henan 450002 , P.R. China
| | - Chuxin Li
- CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences Future Technology College , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Beijing 100190 , P.R. China
| | - Ning Li
- CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences Future Technology College , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Beijing 100190 , P.R. China
| | - Zhouhui Lu
- College of Science , Henan Agricultural University , Zhengzhou , Henan 450002 , P.R. China
| | - Zhichao Dong
- CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences Future Technology College , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Beijing 100190 , P.R. China
| | - Yilin Wang
- Key Laboratory of Colloid and Interface Science, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , P.R. China
| | - Lei Jiang
- CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences Future Technology College , University of Chinese Academy of Sciences, Chinese Academy of Sciences , Beijing 100190 , P.R. China
- School of Chemistry , Beihang University , Beijing 100191 , P.R. China
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Reed JH, Gonsalves AE, Román JK, Oh J, Cha H, Dana CE, Toc M, Hong S, Hoffman JB, Andrade JE, Jo KD, Alleyne M, Miljkovic N, Cropek DM. Ultrascalable Multifunctional Nanoengineered Copper and Aluminum for Antiadhesion and Bactericidal Applications. ACS APPLIED BIO MATERIALS 2019; 2:2726-2737. [DOI: 10.1021/acsabm.8b00765] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Julian H. Reed
- U.S. Army Engineer Research and Development Center, Construction Engineering Research Laboratory (CERL), 2902 Newmark Drive, Champaign, Illinois 61822, United States
| | - Andrew E. Gonsalves
- U.S. Army Engineer Research and Development Center, Construction Engineering Research Laboratory (CERL), 2902 Newmark Drive, Champaign, Illinois 61822, United States
| | - Jessica K. Román
- U.S. Army Engineer Research and Development Center, Construction Engineering Research Laboratory (CERL), 2902 Newmark Drive, Champaign, Illinois 61822, United States
| | - Junho Oh
- Department of Mechanical Science and Engineering, University of Illinois at Urbana−Champaign, 1206 West Green Street, Urbana, Illinois 61801, United States
- International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 8190395, Japan
| | - Hyeongyun Cha
- Department of Mechanical Science and Engineering, University of Illinois at Urbana−Champaign, 1206 West Green Street, Urbana, Illinois 61801, United States
- International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 8190395, Japan
| | - Catherine E. Dana
- Department of Entomology, University of Illinois at Urbana−Champaign, 505 South Goodwin Avenue, Urbana, Illinois 61801, United States
| | - Marco Toc
- Department of Food Science and Human Nutrition, University of Illinois at Urbana−Champaign, 905 South Goodwin Avenue, Urbana, Illinois 61801, United States
| | - Sungmin Hong
- U.S. Army Engineer Research and Development Center, Construction Engineering Research Laboratory (CERL), 2902 Newmark Drive, Champaign, Illinois 61822, United States
| | - Jacob B. Hoffman
- U.S. Army Engineer Research and Development Center, Construction Engineering Research Laboratory (CERL), 2902 Newmark Drive, Champaign, Illinois 61822, United States
| | - Juan E. Andrade
- Department of Food Science and Human Nutrition, University of Illinois at Urbana−Champaign, 905 South Goodwin Avenue, Urbana, Illinois 61801, United States
| | - Kyoo D. Jo
- U.S. Army Engineer Research and Development Center, Construction Engineering Research Laboratory (CERL), 2902 Newmark Drive, Champaign, Illinois 61822, United States
| | - Marianne Alleyne
- Department of Entomology, University of Illinois at Urbana−Champaign, 505 South Goodwin Avenue, Urbana, Illinois 61801, United States
| | - Nenad Miljkovic
- Department of Mechanical Science and Engineering, University of Illinois at Urbana−Champaign, 1206 West Green Street, Urbana, Illinois 61801, United States
- Department of Electrical and Computer Engineering, University of Illinois at Urbana−Champaign, 1206 West Green Street, Urbana, Illinois 61801, United States
- Materials Research Laboratory, University of Illinois at Urbana−Champaign, 104 South Goodwin Avenue, MC-230, Urbana, Illinois 61801, United States
- International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 8190395, Japan
| | - Donald M. Cropek
- U.S. Army Engineer Research and Development Center, Construction Engineering Research Laboratory (CERL), 2902 Newmark Drive, Champaign, Illinois 61822, United States
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Zhang C, Zheng Y, Wu Z, Wang J, Shen C, Liu Y, Ren L. Non-wet kingfisher flying in the rain: The water-repellent mechanism of elastic feathers. J Colloid Interface Sci 2019; 541:56-64. [PMID: 30682593 DOI: 10.1016/j.jcis.2019.01.070] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 01/13/2019] [Accepted: 01/14/2019] [Indexed: 01/28/2023]
Abstract
HYPOTHESIS Flying in the rain presents a greater challenge for smaller animals such as kingfishers, compared with aircraft in the same situation. Regardless, kingfishers have developed advanced water repellency as reflected in the hydrophobicity and elasticity of their feathers. Therefore, it is possible to confirm that the elastic superhydrophobic surface can enhance the water repellency of the surface by experimental and theoretical analysis. EXPERIMENTS A simplified device simulating droplet impact on a kingfisher feather was configured for comparison. Moreover, the dynamic behavior of droplets (with varying Weber numbers-2 ≤ We ≤ 42) impinging on the elastic and rigid substrate was analyzed, such as spreading, retraction, lift-off, the secondary droplet, and contact time with a high-speed camera. FINDINGS The elastic substrate significantly affected the retraction and lift-off of the droplet-that is, an earlier and more efficient morphological rearrangement of the droplet-reducing the contact time by up to 8.3% (17 < We ≤ 32). The combination of elasticity and hydrophobicity is a new bioinspired strategy that provides an insight into one of the mechanisms by which birds flying in the rain cannot be bedewed while guiding the design of water-repellent surfaces.
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Affiliation(s)
- Chengchun Zhang
- Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022, China; State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130022, China.
| | - Yihua Zheng
- Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022, China.
| | - Zhengyang Wu
- Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022, China
| | - Jing Wang
- College of Physics, Jilin University, Changchun 130012, China.
| | - Chun Shen
- State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130022, China.
| | - Yan Liu
- Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022, China
| | - Luquan Ren
- Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022, China
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Joshipura ID, Ayers HR, Castillo GA, Ladd C, Tabor CE, Adams JJ, Dickey MD. Patterning and Reversible Actuation of Liquid Gallium Alloys by Preventing Adhesion on Rough Surfaces. ACS APPLIED MATERIALS & INTERFACES 2018; 10:44686-44695. [PMID: 30532957 DOI: 10.1021/acsami.8b13099] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
This work reports a simple approach to form, study, and utilize rough coatings that prevent the adhesion of gallium-based liquid metal alloys. Typically, liquids with large interfacial tension do not wet nonreactive surfaces, regardless of surface topography. However, these alloys form a surface oxide "skin" that adheres to many substrates, even those with low surface energy. This work reports a simple approach to render closed channels and surfaces, including soft materials, to be "oxide-phobic" via spray-coating (NeverWet, which is commercially available and inexpensive). Surface spectroscopic techniques and metrology tools elucidate the coatings to comprise silica nanoparticles grafted with silicones that exhibit dual length scales of roughness. Although prior work shows the importance of surface roughness in preventing adhesion, the present work confirms that both hydrophobic and hydrophilic rough surfaces prevent oxide adhesion. Furthermore, the coating enables reversible actuation through submillimeter closed channels to form a reconfigurable antenna in the gigahertz range without the need for corrosive acids or bases that remove the oxide. In addition, the coating enables open surface patterning of conductive traces of liquid metal. This shows it is possible to actuate liquid metals in air without leaving neither metal nor oxide residue on surfaces to enable reconfigurable electronics, microfluidics, and soft electrodes.
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Affiliation(s)
| | | | | | | | - Christopher E Tabor
- Materials and Manufacturing Directorate , Air Force Research Laboratories , Wright Patterson , Ohio , United States
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Jamil MI, Ali A, Haq F, Zhang Q, Zhan X, Chen F. Icephobic Strategies and Materials with Superwettability: Design Principles and Mechanism. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:15425-15444. [PMID: 30445813 DOI: 10.1021/acs.langmuir.8b03276] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Ice formation and accretion on surfaces is a serious economic issue in energy supply and transportation. Recent strategies for developing icephobic surfaces are intimately associated with superwettability. Commonly, the superwettability of icephobic materials depends on their surface roughness and chemical composition. This article critically categorizes the possible strategies to mitigate icing problems from daily life. The wettability and classical nucleation theories are used to characterize the icephobic surfaces. Thermodynamically, the advantages/disadvantages of superhydrophobic surfaces are discussed to explain icephobic behavior. The importance of elasticity, slippery liquid-infused porous surfaces (SLIPSs), amphiphilicity, antifreezing protein, organogels, and stimuli-responsive materials has been highlighted to induce icephobic performance. In addition, the design principles and mechanism to fabricate icephobic surfaces with superwettability are explored and summarized.
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Affiliation(s)
- Muhammad Imran Jamil
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering , Zhejiang University , Hangzhou 310027 , China
| | - Abid Ali
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering , Zhejiang University , Hangzhou 310027 , China
| | - Fazal Haq
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering , Zhejiang University , Hangzhou 310027 , China
| | - Qinghua Zhang
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering , Zhejiang University , Hangzhou 310027 , China
| | - Xiaoli Zhan
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering , Zhejiang University , Hangzhou 310027 , China
| | - Fengqiu Chen
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering , Zhejiang University , Hangzhou 310027 , China
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Chen L, Wang Y, Peng X, Zhu Q, Zhang K. Impact Dynamics of Aqueous Polymer Droplets on Superhydrophobic Surfaces. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01589] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Longquan Chen
- School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Yonggui Wang
- Wood Technology and Wood Chemistry, Georg-August-Universität Göttingen, Büsgenweg 4, Göttingen D-37077, Germany
- Key Laboratory of Bio-Based Material Science and Technology (Ministry of Education), College of Material Science and Engineering, Northeast Forestry University, Harbin 150040, Heilongjiang, China
| | - Xiaoyan Peng
- Affiliated Hospital
of Southwest Jiaotong University, Chengdu 610031, China
| | - Qing Zhu
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang 621999, China
| | - Kai Zhang
- Wood Technology and Wood Chemistry, Georg-August-Universität Göttingen, Büsgenweg 4, Göttingen D-37077, Germany
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Joseph J, Krishnan AG, Cherian AM, Rajagopalan B, Jose R, Varma P, Maniyal V, Balakrishnan S, Nair SV, Menon D. Transforming Nanofibers into Woven Nanotextiles for Vascular Application. ACS APPLIED MATERIALS & INTERFACES 2018; 10:19449-19458. [PMID: 29792328 DOI: 10.1021/acsami.8b05096] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
This study investigates the unique properties, fabrication technique, and vascular applications of woven nanotextiles made from low-strength nanoyarns, which are bundles of thousands of nanofibers. An innovative robotic system was developed to meticulously interweave nanoyarns in longitudinal and transverse directions, resulting in a flexible, but strong woven product. This is the only technique for producing seamless nanotextiles in tubular form from nanofibers. The porosity and the mechanical properties of nanotextiles could be substantially tuned by altering the number of nanoyarns per unit area. Investigations of the physical and biological properties of the woven nanotextile revealed remarkable and fundamental differences from its nonwoven nanofibrous form and conventional textiles. This enhancement in the material property was attributed to the multitude of hierarchically arranged nanofibers in the woven nanotextiles. This patterned woven nanotextile architecture leads to a superhydrophilic behavior in an otherwise hydrophobic material, which in turn contributed to enhanced protein adsorption and consequent cell attachment and spreading. Short-term in vivo testing was performed, which proved that the nanotextile conduit was robust, suturable, kink proof, and nonthrombogenic and could act as an efficient embolizer when deployed into an artery.
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Gao S, Liao Q, Liu W, Liu Z. Nanodroplets Impact on Rough Surfaces: A Simulation and Theoretical Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:5910-5917. [PMID: 29708343 DOI: 10.1021/acs.langmuir.8b00480] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Impact of droplets is widespread in life, and modulating the dynamics of impinging droplets is a significant problem in production. However, on textured surfaces, the micromorphologic change and mechanism of impinging nanodroplets are not well-understood; furthermore, the accuracy of the theoretical model for nanodroplets needs to be improved. Here, considering the great challenge of conducting experiments on nanodroplets, a molecular dynamics simulation is performed to visualize the impact process of nanodroplets on nanopillar surfaces. Compared with macroscale droplets, apart from the similar relation of restitution coefficient with the Weber number, we found some distinctive results: the maximum spreading time is described as a power law of impact velocity, and the relation of maximum spreading factor with impact velocity or the Reynolds number is exponential. Moreover, the roughness of substrates plays a prominent role in the dynamics of impact nanodroplets, and on surfaces with lower solid fraction, the lower attraction force induces an easier rebound of impact nanodroplets. At last, on the basis of the energy balance, through modifying the estimation of viscous dissipation and surface energy terms, we proposed an improved model for the maximum spreading factor, which shows greater accuracy for nanodroplets, especially in the low-to-moderate velocity range. The outcome of this study demonstrates that a distinctive dynamical behavior of impinging nanodroplets, the fundamental insight, and more accurate prediction are very useful in the improvement of the hydrodynamic behavior of the nanodroplets.
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Affiliation(s)
- Shan Gao
- School of Energy and Power Engineering , Huazhong University of Science and Technology (HUST) , Wuhan 430074 , China
| | - Quanwen Liao
- School of Energy and Power Engineering , Huazhong University of Science and Technology (HUST) , Wuhan 430074 , China
| | - Wei Liu
- School of Energy and Power Engineering , Huazhong University of Science and Technology (HUST) , Wuhan 430074 , China
| | - Zhichun Liu
- School of Energy and Power Engineering , Huazhong University of Science and Technology (HUST) , Wuhan 430074 , China
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