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Park Y, Ford E. Titanium Oxide Sol–Gel Induced Wrinkling of Electrospun Nanofibers. MACROMOL CHEM PHYS 2018. [DOI: 10.1002/macp.201800028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Yaewon Park
- Department of Textile Engineering Chemistry and Science The Nonwovens Institute North Carolina State University 1020 Main Campus Drive Raleigh NC 27606 USA
| | - Ericka Ford
- Department of Textile Engineering Chemistry and Science The Nonwovens Institute North Carolina State University 1020 Main Campus Drive Raleigh NC 27606 USA
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2
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Aikawa T, Kudo H, Kondo T, Yuasa M. Surface pattern formation on soft polymer substrate through photo-initiated graft polymerization. POLYM ADVAN TECHNOL 2017. [DOI: 10.1002/pat.4029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Tatsuo Aikawa
- Department of Pure and Applied Chemistry, Faculty of Science and Technology; Tokyo University of Science; 2641 Yamazaki Noda Chiba 278-8510 Japan
| | - Hiroaki Kudo
- Department of Pure and Applied Chemistry, Faculty of Science and Technology; Tokyo University of Science; 2641 Yamazaki Noda Chiba 278-8510 Japan
| | - Takeshi Kondo
- Department of Pure and Applied Chemistry, Faculty of Science and Technology; Tokyo University of Science; 2641 Yamazaki Noda Chiba 278-8510 Japan
- Research Institute of Science and Technology; Tokyo University of Science; 2641 Yamazaki Noda Chiba 278-8510 Japan
| | - Makoto Yuasa
- Department of Pure and Applied Chemistry, Faculty of Science and Technology; Tokyo University of Science; 2641 Yamazaki Noda Chiba 278-8510 Japan
- Research Institute of Science and Technology; Tokyo University of Science; 2641 Yamazaki Noda Chiba 278-8510 Japan
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Christian P, Ehmann HMA, Werzer O, Coclite AM. Wrinkle formation in a polymeric drug coating deposited via initiated chemical vapor deposition. SOFT MATTER 2016; 12:9501-9508. [PMID: 27841419 PMCID: PMC5315011 DOI: 10.1039/c6sm01919f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 11/07/2016] [Indexed: 06/06/2023]
Abstract
Polymer encapsulation of drugs is conventionally used as a strategy for controlled delivery and enhanced stability. In this work, a novel encapsulation approach is demonstrated, in which the organic molecule clotrimazole is enclosed into wrinkles of defined sizes. Having defined wrinkles at the drug/encapsulant interface, the contact between the encapsulating polymer and the drug can be improved. In addition, this can also allow for some control on the drug delivery as the available surface area changes with the wrinkle size. For this purpose, thin films of clotrimazole were deposited onto silica substrates and were then encapsulated by crosslinked poly(2-hydroxyethyl methacrylate) (pHEMA) via initiated chemical vapor deposition (iCVD). The thickness and the solid state (crystalline or amorphous) of the clotrimazole layer were varied so that the conditions under which surface wrinkles emerge can be determined. A (critical) clotrimazole thickness of 76.6 nm was found necessary to induce wrinkles, whereby the wrinkle size is directly proportional to the thickness of the amorphous clotrimazole. When the pHEMA was deposited on top of crystalline clotrimazole instead, wrinkling was absent. The wrinkling effect can be understood in terms of elastic mismatch between the relatively rigid pHEMA film and the drug layer. In the case of amorphous clotrimazole, the relatively soft drug layer causes a large mismatch resulting in a sufficient driving force for wrinkle formation. Instead, the increased elastic modulus of crystalline clotrimazole reduces the elastic mismatch between drug and polymer, so that wrinkles do not form.
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Affiliation(s)
- Paul Christian
- Institute of Solid State Physics, NAWI Graz, Graz University of Technology, 8010 Graz, Austria.
| | - Heike M A Ehmann
- Institute of Pharmaceutical Science, Department of Pharmaceutical Technology, University of Graz, 8010 Graz, Austria and BioTechMed, Graz, Austria
| | - Oliver Werzer
- Institute of Pharmaceutical Science, Department of Pharmaceutical Technology, University of Graz, 8010 Graz, Austria and BioTechMed, Graz, Austria
| | - Anna Maria Coclite
- Institute of Solid State Physics, NAWI Graz, Graz University of Technology, 8010 Graz, Austria. and BioTechMed, Graz, Austria
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Hiltl S, Böker A. Wetting Phenomena on (Gradient) Wrinkle Substrates. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:8882-8888. [PMID: 27517879 DOI: 10.1021/acs.langmuir.6b02364] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We characterize the wetting behavior of nanostructured wrinkle and gradient wrinkle substrates. Different contact angles on both sides of a water droplet after deposition on a gradient sample induce the self-propelled motion of the liquid toward smaller wrinkle dimensions. The droplet motion is self-limited by the contact angles balancing out. Because of the correlation between droplet motion and contact angles, we investigate the wetting behavior of wrinkle substrates with constant dimensions (wavelengths of 400-1200 nm). Contact angles of water droplets on those substrates increase with increasing dimensions of the underlying substrate. The results are independent of the two measurement directions, parallel and perpendicular to the longitudinal axis of the nanostructure. The presented findings may be considered for designing microfluidic or related devices and initiate ideas for the development of further wrinkle applications.
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Affiliation(s)
- Stephanie Hiltl
- Fraunhofer-Institut für Angewandte Polymerforschung IAP, D-14476 Potsdam-Golm, Germany
| | - Alexander Böker
- Fraunhofer-Institut für Angewandte Polymerforschung IAP, D-14476 Potsdam-Golm, Germany
- Lehrstuhl für Polymermaterialien und Polymertechnologien, Universität Potsdam , D-14476 Potsdam-Golm, Germany
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Debuisson D, Merlen A, Senez V, Arscott S. Stick-Jump (SJ) Evaporation of Strongly Pinned Nanoliter Volume Sessile Water Droplets on Quick Drying, Micropatterned Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:2679-2686. [PMID: 26950673 DOI: 10.1021/acs.langmuir.6b00070] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present an experimental study of stick-jump (SJ) evaporation of strongly pinned nanoliter volume sessile water droplets drying on micropatterned surfaces. The evaporation is studied on surfaces composed of photolithographically micropatterned negative photoresist (SU-8). The micropatterning of the SU-8 enables circular, smooth, trough-like features to be formed which causes a very strong pinning of the three phase (liquid-vapor-solid) contact line of an evaporating droplet. This is ideal for studying SJ evaporation as it contains sequential constant contact radius (CCR) evaporation phases during droplet evaporation. The evaporation was studied in nonconfined conditions, and forced convection was not used. Micropatterned concentric circles were defined having an initial radius of 1000 μm decreasing by a spacing ranging from 500 to 50 μm. The droplet evaporates, successively pinning and depinning from circle to circle. For each pinning radius, the droplet contact angle and volume are observed to decrease quasi-linearly with time. The experimental average evaporation rates were found to decrease with decreasing pining radii. In contrast, the experimental average evaporation flux is found to increase with decreasing droplet radii. The data also demonstrate the influence of the initial contact angle on evaporation rate and flux. The data indicate that the total evaporation time of a droplet depends on the specific micropattern spacing and that the total evaporation time on micropatterned surfaces is always less than on flat, homogeneous surfaces. Although the surface patterning is observed to have little effect on the average droplet flux-indicating that the underlying evaporation physics is not significantly changed by the patterning-the total evaporation time is considerably modified by patterning, up to a factor or almost 2 compared to evaporation on a flat, homogeneous surface. The closely spaced concentric circle pinning maintains a large droplet radius and small contact angle from jump to jump; the result is a large evaporation rate leading to faster evaporation.
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Affiliation(s)
- Damien Debuisson
- Institut d'Electronique, de Microélectronique et de Nanotechnologie (IEMN), CNRS UMR 8520, The University of Lille , Cité Scientifique, Avenue Poincaré, 59652 Villeneuve d'Ascq, France
| | - Alain Merlen
- Institut d'Electronique, de Microélectronique et de Nanotechnologie (IEMN), CNRS UMR 8520, The University of Lille , Cité Scientifique, Avenue Poincaré, 59652 Villeneuve d'Ascq, France
| | - Vincent Senez
- Institut d'Electronique, de Microélectronique et de Nanotechnologie (IEMN), CNRS UMR 8520, The University of Lille , Cité Scientifique, Avenue Poincaré, 59652 Villeneuve d'Ascq, France
| | - Steve Arscott
- Institut d'Electronique, de Microélectronique et de Nanotechnologie (IEMN), CNRS UMR 8520, The University of Lille , Cité Scientifique, Avenue Poincaré, 59652 Villeneuve d'Ascq, France
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Goel P, Kumar S, Sarkar J, Singh JP. Mechanical Strain Induced Tunable Anisotropic Wetting on Buckled PDMS Silver Nanorods Arrays. ACS APPLIED MATERIALS & INTERFACES 2015; 7:8419-8426. [PMID: 25844957 DOI: 10.1021/acsami.5b01530] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report the fabrication of anisotropic superhydrophobic surface with dual-scale roughness by the deposition of silver nanorods arrays on prestretched poly(dimethylsiloxane) (PDMS) using oblique angle deposition and subsequent release of strain after the deposition, which resulted in the formation of microbuckles/wrinkles. The amplitude and periodicity of the wrinkles were tuned by varying the prestretching mechanical strain (ε) applied to the PDMS film from 0 to 30% prior to Ag nanorods deposition. The peaks and valleys in the surface topography of Ag nanorods arrays covered PDMS films lead to anisotropic wetting by water droplet. The droplet is free to move along the direction parallel to the wrinkles, but the droplet moving perpendicular to the wrinkles confront energy barrier leading to wetting anisotropy. The anisotropic wettability was tuned from 22 to 37° for 10-30% prestretched PDMS film. The dual scale roughness (nanorods on micro wrinkles) was found to be responsible for the superhydrophobicity (contact angle ∼155°) of the sample prepared for 30% prestretched PDMS film in perpendicular direction. The wetting behavior of the Ag nanorods PDMS film surface was reversibly tuned by applying the mechanical strain, which induces the change in the microscale roughness determined by amplitude (A) and periodicity (λ) of the buckles. Most interestingly, the water droplet also displayed the anisotropy in the roll-off angle. The effect of different A and λ on anisotropic wettability of Ag nanorods arrays/PDMS film was also demonstrated by lattice Boltzmann (LB) modeling. These findings may produce a promising way of controlling the direction of liquid flow such as in microfluidic devices and transportation of the microliter water droplets in a preset direction.
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Affiliation(s)
- Pratibha Goel
- †Department of Physics and ‡Department of Chemical Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Samir Kumar
- †Department of Physics and ‡Department of Chemical Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Jayati Sarkar
- †Department of Physics and ‡Department of Chemical Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Jitendra P Singh
- †Department of Physics and ‡Department of Chemical Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
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Microscopic receding contact line dynamics on pillar and irregular superhydrophobic surfaces. Sci Rep 2015; 5:8384. [PMID: 25670630 PMCID: PMC4323644 DOI: 10.1038/srep08384] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 01/19/2015] [Indexed: 11/08/2022] Open
Abstract
Receding angles have been shown to have great significance when designing a superhydrophobic surface for applications involving self-cleaning. Although apparent receding angles under dynamic conditions have been well studied, the microscopic receding contact line dynamics are not well understood. Therefore, experiments were performed to measure these dynamics on textured square pillar and irregular superhydrophobic surfaces at micron length scales and at micro-second temporal scales. Results revealed a consistent "slide-snap" motion of the microscopic receding line as compared to the "stick-slip" dynamics reported in previous studies. Interface angles between 40-60° were measured for the pre-snap receding lines on all pillar surfaces. Similar "slide-snap" dynamics were also observed on an irregular nanocomposite surface. However, the sharper features of the surface asperities resulted in a higher pre-snap receding line interface angle (~90°).
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Chen YC, Crosby AJ. High aspect ratio wrinkles via substrate prestretch. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:5626-5631. [PMID: 24863587 DOI: 10.1002/adma.201401444] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 04/26/2014] [Indexed: 06/03/2023]
Abstract
A non-fractured, high aspect ratio wrinkled surface is successfully fabricated. Building upon recently developed models of the localization transition and the current knowledge of surface failures, the wrinkling mode is stabilized at high strain, doubling the accessible wrinkling aspect ratio to the currently reported value. This high aspect ratio surface provides significant promise for future wrinkle-based applications.
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Affiliation(s)
- Yu-Cheng Chen
- University of Massachusetts Amherst, 120 Governors Drive, Amherst, MA, 01003, USA
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Schmitt M, Heib F. High-precision drop shape analysis on inclining flat surfaces: introduction and comparison of this special method with commercial contact angle analysis. J Chem Phys 2014; 139:134201. [PMID: 24116561 DOI: 10.1063/1.4822261] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Drop shape analysis is one of the most important and frequently used methods to characterise surfaces in the scientific and industrial communities. An especially large number of studies, which use contact angle measurements to analyse surfaces, are characterised by incorrect or misdirected conclusions such as the determination of surface energies from poorly performed contact angle determinations. In particular, the characterisation of surfaces, which leads to correlations between the contact angle and other effects, must be critically validated for some publications. A large number of works exist concerning the theoretical and thermodynamic aspects of two- and tri-phase boundaries. The linkage between theory and experiment is generally performed by an axisymmetric drop shape analysis, that is, simulations of the theoretical drop profiles by numerical integration onto a number of points of the drop meniscus (approximately 20). These methods work very well for axisymmetric profiles such as those obtained by pendant drop measurements, but in the case of a sessile drop onto real surfaces, additional unknown and misunderstood effects on the dependence of the surface must be considered. We present a special experimental and practical investigation as another way to transition from experiment to theory. This procedure was developed to be especially sensitive to small variations in the dependence of the dynamic contact angle on the surface; as a result, this procedure will allow the properties of the surface to be monitored with a higher precession and sensitivity. In this context, water drops onto a 111 silicon wafer are dynamically measured by video recording and by inclining the surface, which results in a sequence of non-axisymmetric drops. The drop profiles are analysed by commercial software and by the developed and presented high-precision drop shape analysis. In addition to the enhanced sensitivity for contact angle determination, this analysis technique, in combination with innovative fit algorithms and data presentations, can result in enhanced reproducibility and comparability of the contact angle measurements in terms of the material characterisation in a comprehensible way.
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Affiliation(s)
- Michael Schmitt
- Physical Chemistry, Saarland University, 66123 Saarbrücken, Germany
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Gaillard JG, Hendrus C, Vogt BD. Tunable wrinkle and crease surface morphologies from photoinitiated polymerization of furfuryl alcohol. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:15083-15089. [PMID: 24205841 DOI: 10.1021/la4038167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Addition of a small fraction of hydrophobic photoacid generator (PAG) to furfuryl alcohol provides a facile route to generate wrinkle topology by acid-catalyzed polymerization that is induced by ultraviolet (UV) light. Here, we describe how the primary characteristic parameters, wavelength and amplitude, of these periodic wrinkles can be tuned through control of the thickness of this furfuryl alcohol-PAG solution prior to UV exposure and the environmental humidity. As the initial coating thickness is increased, the wavelength remains unchanged at fixed temperature and PAG concentration, but the amplitude of the wrinkles increases exponentially with increased coating thickness. A wrinkle to crease transition is observed in some cases as the thickness of the solution coating is increased; this behavior is dependent on the PAG selection. Conversely, variation in relative humidity does not significantly impact the amplitude of the wrinkles, but there is a step change in the wavelength of the wrinkles near approximately 45% relative humidity with a factor of 3 decrease in the wavelength at high humidity. Through this knowledge, we have been able to fabrication wrinkles with an aspect ratio greater than 0.7 in a single step by UV exposure. These simple processing parameters to independently control wavelength and amplitude provide a facile route to systematically examine the role of aspect ratio of wrinkles on physical properties.
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Affiliation(s)
- James G Gaillard
- Department of Biomedical Engineering, University of Akron , Akron, Ohio 44325, United States
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Lai Y, Chen J, Zhang T, Gu D, Zhang C, Li Z, Lin S, Fu X, Schultze-Mosgau S. Effect of 3D microgroove surface topography on plasma and cellular fibronectin of human gingival fibroblasts. J Dent 2013; 41:1109-21. [PMID: 23948393 DOI: 10.1016/j.jdent.2013.08.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 08/02/2013] [Accepted: 08/03/2013] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVES Fibronectin (FN), an extracellular matrix (ECM) glycoprotein, is a key factor in the compatibility of dental implant materials. Our objective was to determine the optimal dimensions of microgrooves in the transmucosal part of a dental implant, for optimal absorption of plasma FN and expression of cellular FN by human gingival fibroblasts (HGFs). METHODS Microgroove titanium surfaces were fabricated by photolithography with parallel grooves: 15μm, 30μm, or 60μm in width and 5μm or 10μm in depth. Smooth titanium surfaces were used as controls. Surface hydrophilicity, plasma FN adsorption and cellular FN expression by HGFs were measured for both microgroove and control samples. RESULTS We found that narrower and deeper microgrooves amplified surface hydrophobicity. A 15-μm wide microgroove was the most hydrophobic surface and a 60-μm wide microgroove was the most hydrophilic. The latter had more expression of cellular FN than any other surface, but less absorption of plasma FN than 15-μm wide microgrooves. Variation in microgroove depth did not appear to effect FN absorption or expression unless the groove was narrow (∼15 or 30μm). In those instances, the shallower depths resulted in greater expression of cellular FN. CONCLUSIONS Our microgrooves improved expression of cellular FN, which functionally compensated for plasma FN. A microgroove width of 60μm and depth of 5 or 10μm appears to be optimal for the transmucosal part of the dental implant.
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Affiliation(s)
- Yingzhen Lai
- School of Stomatology, Fujian Medical University, Fuzhou, Fujian 350000, China
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Yin J, Yagüe JL, Eggenspieler D, Gleason KK, Boyce MC. Deterministic order in surface micro-topologies through sequential wrinkling. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2012; 24:5441-6. [PMID: 22915065 DOI: 10.1002/adma.201201937] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 07/17/2012] [Indexed: 05/11/2023]
Abstract
Ordered herringbone patterns with deterministic long and short wavelengths are created using a sequential wrinkling strategy (SWS). Patterns with a prescribed zig-zag turning angle less than 90° are obtained upon sequential wrinkling of non-equi-biaxial prestrain for the first time. SWS provides a new method for measuring thin-film mechanical properties simply through the wrinkling metrology without measurement of film thickness.
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Affiliation(s)
- Jie Yin
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Mao ZS, Yang C, Chen J. Mathematical modeling of a hydrophilic cylinder floating on water. J Colloid Interface Sci 2012; 377:463-8. [PMID: 22520711 DOI: 10.1016/j.jcis.2012.03.081] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 03/27/2012] [Accepted: 03/28/2012] [Indexed: 11/29/2022]
Abstract
In this paper, a hydrostatic model of the surface profile anchored to the upper edge of a vertical cylinder is proposed to explain why coins can float on water surface. The sharp edge of a cylinder is thus modeled as a round smooth surface on which the contact line may be anchored at a position according to the weight of the cylinder. The mathematical model of the surface profile is established based on the hydrostatics and a third order ordinary differential equation is resulted. Numerical solution of the model demonstrates under practical conditions the existence of the surface profiles that provide reasonable uplifting force at the contact line so that the force is available for floating coins on water surface. The proposed model explains the obviously enlarged apparent contact angle and the edge effect in the literature. The numerical simulation is found in very good agreement with the experimental data in the literature.
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Affiliation(s)
- Zai-Sha Mao
- Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
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Insights into the static and advancing water contact angles on surfaces anisotropised with aligned fibers: Experiments and modeling. Colloids Surf A Physicochem Eng Asp 2011. [DOI: 10.1016/j.colsurfa.2011.08.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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