Über die Ausbreitungsgeschwindigkeit von Öl auf Wasser

Landt, E.; Volmer, M.

doi:10.1515/zpch-1926-12230

Cited by 23 publications

(18 citation statements)

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“…͑3͒. 3,7,13,27,28 All previous experiments were conducted in rectilinear geometry with a constant concentration source provided by an infinite reservoir. Our spreading experiments also use an effective infinite reservoir ͑on the time scale of our measurements͒ but the spreading occurs in axisymmetric geometry.…”

Section: B Control Study With Nonvolatile Films: Spreading Of Silicomentioning

confidence: 99%

Dynamics of spontaneous spreading with evaporation on a deep fluid layer

Dussaud¹,

Troian²

1998

Physics of Fluids

118

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The spontaneous spreading of a thin volatile film along the surface of a deep fluid layer of higher surface tension provides a rapid and efficient transport mechanism for many technological applications. This spreading process is used, for example, as the carrier mechanism in the casting of biological and organic Langmuir-Blodgett films. We have investigated the dynamics of spontaneously spreading volatile films of different vapor pressures and spreading coefficients advancing over the surface of a deep water support. Laser shadowgraphy was used to visualize the entire surface of the film from the droplet source to the leading edge. This noninvasive technique, which is highly sensitive to the film surface curvature, clearly displays the location of several moving fronts. In this work we focus mainly on the details of the leading edge. Previous studies of the spreading dynamics of nonvolatile, immiscible thin films on a deep liquid layer have shown that the leading edge advances in time as t 3/4 as predicted by laminar boundary layer theory. We have found that the leading edge of volatile, immiscible spreading films also advances as a power law in time, t ␣ , where ␣ϳ1/2. Differences in the liquid vapor pressure or the spreading coefficient seem only to affect the speed of advance but not the value of the spreading exponent, which suggests the presence of a universal scaling law. Sideview laser shadowgraphs depicting the subsurface motion in the water reveal the presence of a single stretched convective roll right beneath the leading edge of the spreading film. This fluid circulation, likely caused by evaporation and subsequent surface cooling of the rapidly spreading film, resembles a propagating Rayleigh-Bénard convective roll. We propose that this sublayer rotational flow provides the additional dissipation responsible for the reduced spreading exponent.

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Section: B Control Study With Nonvolatile Films: Spreading Of Silicomentioning

confidence: 99%

Dynamics of spontaneous spreading with evaporation on a deep fluid layer

Dussaud¹,

Troian²

1998

Physics of Fluids

118

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“…The surface tension of the precursor film, σ , changes with film thickness from σ 2 at the very outer edge of the precursor film to σ 1 + σ 12 at the main drop periphery. Based on this picture, Foda and Cox (7) demonstrate that the transient radius of the precursor film, R(t), obeys a simple power law apparently first put forward by Landt and Volmer (1),…”

Section: Introductionmentioning

confidence: 83%

“…Accordingly, numerous studies, both experimental and theoretical, are available, primarily for pure spreading liquids (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). According to Harkins and Feldman (16) spreading occurs when S is positive.…”

Section: Introductionmentioning

confidence: 99%

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A Sorption-Kinetic Model for Surfactant-Driven Spreading of Aqueous Drops on Insoluble Liquid Substrates

Chauhan

Svitova

Radke

2000

Journal of Colloid and Interface Science

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“…While early experiments in rectilinear geometry [6][7][8][9][10] suggested that the prefactor k is dependent on film constitutive behavior, later experiments by Camp and Berg 11,12 demonstrated that this constant depends only on spreading geometry. Recent calculations 13 suggest universal values of kϭ1.4150 for rectilinear spreading ͑in good agreement with Camp and Berg's 11,12 experimental value of 1.4Ϯ0.04) and kϭ1.0754 for axisymmetric spreading.…”

Section: ͑1͒mentioning

confidence: 99%

Fluorescence visualization of a convective instability which modulates the spreading of volatile surface films

1998

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The spontaneous spreading of a thin liquid film along the surface of a deep liquid layer of higher surface tension is a ubiquitous process which provides rapid and efficient surface transport of organic or biological material. For a source of constant concentration, the leading edge of a nonvolatile, immiscible film driven to spread by gradients in surface tension is known to advance as t 3/4 in time. Recent experiments using laser shadowgraphy to detect the advancing front of spreading films indicate, however, that immiscible but volatile sources of constant concentration spread with a reduced exponent according to t 1/2. Using a novel technique whereby fluorescent lines are inscribed in water, we have detected the evolution of a thermal instability beneath the leading edge of volatile films which strongly resembles a Rayleigh-Bénard roll. We propose that the increased dissipation from this rotational flow structure is likely responsible for the reduction in spreading exponent. This observation suggests a conceptual framework for coupling the effects of evaporation to the dynamics of spreading. © 1998 American Institute of Physics. ͓S1070-6631͑98͒01607-9͔ I. SPONTANEOUS SPREADING ON A DEEP LIQUID LAYERWhen a liquid substrate is contacted by a film of lower surface tension, surface traction is produced in proportion to the difference in surface tension between the liquid support and the spreading film. This traction creates rapid and spontaneous flow toward regions of higher surface tension. The speed of the spreading film is known to increase with the magnitude of the spreading coefficient defined by Sϭ␥ 1 Ϫ␥ 2 Ϫ␥ 12 , where ␥ 1 denotes the surface tension of the clean liquid support, ␥ 2 the surface tension of the spreading film, and ␥ 12 the interfacial tension between the spreading film and supporting liquid.1 This spreading coefficient is related to the local gradient in surface tension, ‫,‪x‬ץ/␥ץ‬ through the relation Sϭ͐ 0 L(t) ‫‪x‬ץ/␥ץ‬ dx, where the coordinate x denotes the horizontal or radial direction of spreading and L(t) denotes the length of the surface active film at time t after contact with the liquid support. In the examples discussed below, the gradients in surface tension are caused by variations in the surface concentration, ⌫, of the spreading film where ‫.)‪x‬ץ/⌫ץ()⌫ץ/␥ץ(‪xϭ‬ץ/␥ץ‬ The spontaneous advance of a surface film driven by this type of shear stress is called Marangoni driven spreading, 2 which occurs for positive values of the spreading coefficient. A small scale example of this spreading process occurs during the casting of Langmuir-Blodgett films. In the fabrication of these films, organic or biological molecules are dissolved in a solvent like hexane or carbon tetrachloride which spreads rapidly and spontaneously over the surface of water. The organic solvent, which has a lower surface tension than pure water, acts as the carrier liquid to transport molecules along the water surface under the action of Marangoni stresses. 3 The solvent film eventually evaporates leaving behin...

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Über die Ausbreitungsgeschwindigkeit von Öl auf Wasser

Cited by 23 publications

References 0 publications

Dynamics of spontaneous spreading with evaporation on a deep fluid layer

Dynamics of spontaneous spreading with evaporation on a deep fluid layer

A Sorption-Kinetic Model for Surfactant-Driven Spreading of Aqueous Drops on Insoluble Liquid Substrates

Fluorescence visualization of a convective instability which modulates the spreading of volatile surface films

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