A new oscillating bubble technique for measuring surface dilational properties

Fruhner, H.; Wantke, K. D.

doi:10.1016/0927-7757(96)03561-3

Cited by 63 publications

(46 citation statements)

References 8 publications

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“…Several models that describe the dynamic behavior of fluid surfaces are established. But experiments in the medium frequency range, e.g., with the oscillating bubble method, exhibit discrepancies to the theoretical models [8][9][10][11]. The reason is probably the assumptions about the structure of the adsorption layer under dynamic conditions.…”

Section: Aims Of the Experimentsmentioning

confidence: 94%

“…In the slightly extended model including a surface consisting of a sublayer and monolayer described in this paper and in previous pa- Table 1. pers [8][9][10][11], the experimental results may be explained if the molecular exchange between the sublayer and the monolayer is fast in comparison to the deformation rate. The monolayer, the sublayer and the adjacent topmost layer of the bulk are then in equilibrium during the whole deformation cycle, and the model becomes equal to the LvdT model.…”

Section: Tensiometry In the Oscillating Bubble Configurationmentioning

confidence: 99%

“…It is introduced for formal reasons to characterize the influence of dissipative losses within the surface layer on the surface tension. Experimental results request this term [8][9][10][11][12][13][14]. Here we consider only the compositional effects because the solution used shows no influence of an intrinsic surface dilatational viscosity (κ = 0).…”

Section: ( A) γ ( A) and C S ( A)mentioning

confidence: 99%

“…The surface dilatational modulus ε(f, c) was determined with the oscillating bubble method [4,8,9]. Within a closed chamber a small hemispherical bubble is produced at the tip of a capillary.…”

Section: Measurement Of the Surface Dilatational Modulus With The Oscmentioning

confidence: 99%

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A study of kinetic molecular exchange processes in the medium frequency range by surface SHG on an oscillating bubble

Örtegren

Wantke

Motschmann

et al. 2004

Journal of Colloid and Interface Science

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The dilatational properties of fluid surfaces and interfaces have been comprehensively investigated in recent years. For example, an improved oscillating bubble device provided experimental results that allow for critical testing of established surface models, such as the Lucassen/van den Tempel (LvdT) model. The comparison of the LvdT model with the oscillating bubble experiments demonstrates a mismatch between the model parameters. For example, near the CMC or the limit of solubility the calculated parameters of surfactant solutions become unrealistically large. The deviation can be explained by the introduction of more detailed surface models, in particular by the modification of the effective thickness of the surface layer, its internal structure and the molecular exchange processes between these structures. For the verification of such processes an experimental setup was realized which allows for an independent determination of the instantaneous adsorption state at the surface of an oscillating bubble inside a surfactant solution. The setup utilizes the Second Harmonic Generation (SHG)-effect at the air-solution interface generated by the light of a pulsed LASER. The set-up is described in detail, and the results of a first experimental series are presented and discussed in this paper. As system, aqueous solutions of the fluortenside F381 were used.  2004 Elsevier Inc. All rights reserved.

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Section: Aims Of the Experimentsmentioning

confidence: 94%

Section: Tensiometry In the Oscillating Bubble Configurationmentioning

confidence: 99%

Section: ( A) γ ( A) and C S ( A)mentioning

confidence: 99%

Section: Measurement Of the Surface Dilatational Modulus With The Oscmentioning

confidence: 99%

See 2 more Smart Citations

A study of kinetic molecular exchange processes in the medium frequency range by surface SHG on an oscillating bubble

Örtegren

Wantke

Motschmann

et al. 2004

Journal of Colloid and Interface Science

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“…The scheme, in which the upper cell was open, was used in [81]. The variant of measurements using a closed upper cell was described in [82,83]. The implementation of this method suggests a broad potential for measuring viscoelastic properties of interfacial layers of surfactants, including all classical schemes of relaxation experiments, e.g., periodic deformations [84], as well as the relaxation of interfacial layers induced by transient changes in the surface area of a droplet induced via changes in its volume [85].…”

Section: Methods Based On the Oscillationmentioning

confidence: 99%

Methods of measuring rheological properties of interfacial layers (Experimental methods of 2D rheology)

2009

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-Current methods of studying the rheological properties of interfacial layers at the interfaces of fluids are reviewed. This area of research includes two-dimensional 2D rheology. Regardless of the similarities between the parameters of rheological properties of two-dimensional and bulk (three-dimensional) systems, when measuring surface properties, it is necessary to reformulate the main experimental methods to allow for the different dimensions of surface and bulk characteristics of material. Parameters of shear and dilational (measured upon expansion-compression) properties of interfacial layers are distinguished, and the latter are considered to be independent parameters of a system. The most attention was given to the rotational methods of measuring shear viscosity and the components of the complex 2D elastic modulus, as well as to measuring surface tension upon harmonic changes of the bubble (droplet) surface area, which allows characteristics of the dilational behavior of thin liquid films to be determined. Both groups of methods are widely used in laboratory practice and realized in the form of a number of original and commercial instruments. Dilational measurements of interfacial layers can also be performed with oscillations of a movable barrier on a Langmuir trough. In addition, methods based on the propagation of capillary waves across the surface of a liquid, as well as rarer methods of capillary flow in thin channels forced by either a surface tension gradient or the motion of the interface, are considered.

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