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Contact angle

About: Contact angle is a research topic. Over the lifetime, 34693 publications have been published within this topic receiving 945925 citations.


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01 Jan 1979
TL;DR: In this paper, it is shown that the mutual interaction between the three materials in the immediate vicinity of a contact line can significantly affect the statics as well as the dynamics of an entire flow field.
Abstract: A contact line is formed at the intersection of two immiscible fluids and a solid. That the mutual interaction between the three materials in the immediate vicinity of a contact line can significantly affect the statics as well as the dynamics of an entire flow field is demonstrated by the behavior of two immiscible fluids in a capillary. It is well known that the height to which a column of liquid will rise in a vertical circular capillary with small radius, a, whose lower end is placed into a bath, is given by (2(j/apg) cos (), where (j is the surface tension of the air/liquid interface, f) is the static contact angle as measured from the liquid side of the contact line, p is the density, and g is the magnitude of the accelera­ tion due to gravity.! Thus, depending on the value of the contact angle, e, which is a direct consequence of the molecular interactions among the three materials at the contact line, the height can take on any value within the interval [ 2(J/apg, 2(J/apg]. In a sense, the influence of the contact angle is indirect: the contact angle, in capillaries with small radii, controls the radius of curvature of the meniscus which, in turn, regulates the pressure in the liquid under the meniscus. It is this pressure that determines the height of the column. In a similar manner, the dynamic contact angle can influence the rate of displacement of tbe meniscus through the capillary. The pressure drop

1,169 citations

Book
07 Nov 2003
TL;DR: In this article, the authors present an analysis of Diffraction patterns on the surface of liquid surfaces of liquid and liquid liquids. But their focus is on the electric double layer of the double layer.
Abstract: 1. Introduction 2. Liquid Surfaces 3. Thermodynamics of Interfaces 4. Charged Interfaces and the Electric Double Layer 5. Surface Forces 6. Contact Angle Phenomena and Wetting 7. Solid Surfaces 8. Adsorption 9. Surface Modification 10. Friction, Lubrication, and Wear 11. Surfactants, Micelles, Emulsions, and Foams 12. Thin Films on Surfaces of Liquids 13. Solutions to Exercises 14. Analysis of Diffraction Patterns

1,157 citations

Journal ArticleDOI
TL;DR: In this paper, a linear relationship between the contact angle and the water monomer binding energy on graphite was established and a new route to calibrate interaction potential parameters was presented, which was obtained by applying a carbon−oxygen Lennard-Jones potential with parameters eCO = 0.392 kJ mol-1 and σCO = 3.19 A.
Abstract: A systematic molecular dynamics study shows that the contact angle of a water droplet on graphite changes significantly as a function of the water−carbon interaction energy. Together with the observation that a linear relationship can be established between the contact angle and the water monomer binding energy on graphite, a new route to calibrate interaction potential parameters is presented. Through a variation of the droplet size in the range from 1000 to 17 500 water molecules, we determine the line tension to be positive and on the order of 2 × 10-10 J/m. To recover a macroscopic contact angle of 86°, a water monomer binding energy of −6.33 kJ mol-1 is required, which is obtained by applying a carbon−oxygen Lennard-Jones potential with the parameters eCO = 0.392 kJ mol-1 and σCO = 3.19 A. For this new water−carbon interaction potential, we present density profiles and hydrogen bond distributions for a water droplet on graphite.

1,155 citations

Journal ArticleDOI
24 Apr 1999-Langmuir
TL;DR: In this article, the preparation of ultrahydrophobic and ultralyophobic surfaces using several techniques is described, and the authors emphasize that contact angle hysteresis is more important in characterizing lyophobicity than is the maximum achievable contact angle.
Abstract: The preparation of ultrahydrophobic and ultralyophobic surfaces using several techniques is described. Plasma polymerization of 2,2,3,3,4,4,4-heptafluorobutyl acrylate on poly(ethylene terephthalate) yields surfaces with water contact angles of θA/θR = 174°/173°. Argon plasma etching of polypropylene in the presence of poly(tetrafluoroethylene) renders surfaces with water contact angles as high as θA/θR = 172°/169°. Surfaces of compressed pellets of submicrometer, variable-diameter spherical particles of PTFE oligomers exhibit water contact angles of θA/θR = 177°/177°, methylene iodide contact angles of θA/θR = 140°/138°, and hexadecane contact angles of θA/θR = 140°/125°. We emphasize that contact angle hysteresis is more important in characterizing lyophobicity than is the maximum achievable contact angle. These surfaces are rough at the micrometer and submicrometer scales, and water drops roll easily on all of them. We make an intuitive argument that the topology of the roughness is important and contr...

1,147 citations

Journal ArticleDOI
TL;DR: Four design parameters are proposed that predict the measured contact angles for a liquid droplet on a textured surface, as well as the robustness of the composite interface, based on the properties of the solid surface and the contacting liquid, that allow two different families of re-entrant surfaces to be produced.
Abstract: Superhydrophobic surfaces display water contact angles greater than 150° in conjunction with low contact angle hysteresis. Microscopic pockets of air trapped beneath the water droplets placed on these surfaces lead to a composite solid-liquid-air interface in thermodynamic equilibrium. Previous experimental and theoretical studies suggest that it may not be possible to form similar fully-equilibrated, composite interfaces with drops of liquids, such as alkanes or alcohols, that possess significantly lower surface tension than water (γlv = 72.1 mN/m). In this work we develop surfaces possessing re-entrant texture that can support strongly metastable composite solid-liquid-air interfaces, even with very low surface tension liquids such as pentane (γlv = 15.7 mN/m). Furthermore, we propose four design parameters that predict the measured contact angles for a liquid droplet on a textured surface, as well as the robustness of the composite interface, based on the properties of the solid surface and the contacting liquid. These design parameters allow us to produce two different families of re-entrant surfaces— randomly-deposited electrospun fiber mats and precisely fabricated microhoodoo surfaces—that can each support a robust composite interface with essentially any liquid. These omniphobic surfaces display contact angles greater than 150° and low contact angle hysteresis with both polar and nonpolar liquids possessing a wide range of surface tensions.

1,132 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20232,127
20224,212
20211,891
20201,831
20192,013
20181,999