Method for direct measurement of the film tension of black foam films at various capillary pressures

Platikanov, Dimo; Nedyalkov, M.; Rangelova, Nadezhda

doi:10.1007/bf01422667

Cited by 19 publications

(3 citation statements)

References 7 publications

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“…This result can be explained with the high solubility of SDS and with the great facility of sorption and desorption of this surfactant from the film surfaces. As previously reported [22,39,40], the results obtained by means of the same method for films of different solutions of phospholipids and mixtures of phospholipids differ from those for the SDS film; a hystheresis of the contact angle is observed for all these films. The results obtained in the present study for the time dependence of 2θ for the ALG, BLG, and BSA films are shown in Figs.…”

Section: Dynamic Contact Angle Of Protein Black Filmssupporting

confidence: 65%

Contact angles of protein black foam films under dynamic and equilibrium conditions

2007

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Abstract:The contact angles of protein Newton black foam films from ALG (alpha-lactalbumin), BLG (beta-lactoglobulin) and BSA (bovine serum albumin) are measured here within. The measurements are carried out under dynamic and equilibrium conditions. For all proteins, a strong hystheresis effect of the contact angle is observed under dynamic conditions. An attempt is made to explain these results by the slow adsorption and desorption kinetics of the protein bilayers and by the dynamic structure and the rheology of the protein network forming the bubble walls. In addition, we propose a modification of the experimental device reported previously for contact angle measurements of large flat films in equilibrium. The advantages of this method are discussed in detail. Some shortcomings (precision, reproducibility) of this preliminary variant of the device in this initial stage of its application, do not allow one to draw reliable conclusions about the interactions of these films. Some improvements of the measurement quality are proposed.

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Section: Dynamic Contact Angle Of Protein Black Filmssupporting

confidence: 65%

Contact angles of protein black foam films under dynamic and equilibrium conditions

2007

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“…All of these approaches make use of a spherical drop or bubble and relate the simple geometric parameters of the sphere to the Laplace equation of capillarity to calculate film tension. Platikanov et al , reported an experimental method for direct measurement of the film tension of black foam films. Their foam films are obtained in the form of a spherical semibubble, whose radius of curvature is determined from microphotographs and the capillary pressure is measured by a manometer.…”

Section: Discussionmentioning

confidence: 99%

“…It is the purpose of this work to design an experiment that will record the dynamics of film thinning and film rupture, i.e., to develop a new methodology for measuring film tension. This is significant since, presently, compared to the number of techniques for measuring interfacial tension, only a small number of methods − have been developed for measuring film tension. All of these approaches make use of a spherical drop or bubble and relate the simple geometric parameters of the sphere to the Laplace equation of capillarity in order to calculate film tension.…”

Section: Introductionmentioning

confidence: 99%

Film Tension and Film Rupture of Alkanes at the Air−Water Interface Using Axisymmetric Drop Shape Analysis

et al. 1998

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In connection with interfacial tension measurements for n-hexadecane-water under conditions of mutual saturation, we accidentally found an extremely high tension value for the aqueous phase of approximately 80 mJ/m 2 , using axisymmetric drop shape analysis-profile (ADSA-P) for an air bubble formed in the water phase. This high tension value is that of an alkane film at the air-water interface. From static measurements (the drop surface area kept constant) at 25 ( 0.2 °C, we observed this film tension value to be 80.67 ( 0.06 and 77.20 ( 0.02 mJ/m 2 at the 95% confidence level for hexadecane and dodecane films at the air-water interface, respectively. These film tension values were also confirmed in dynamic measurements (the drop surface area continuously increased) for both alkane systems. In addition, film rupture has been demonstrated both in the sudden change in the bubble profile and in the abrupt decrease in the tension value. The alkane film tension measured is approximately equal to the sum of the interfacial tensions of air-alkane and alkanewater. The method presented provides a new way to measure film tension; it utilizes axisymmetric drops or bubbles. This is less restrictive than other approaches that require the drop or bubble to be spherical. The measurements for film tension can be carried out under both static and dynamic conditions, and information about the surface area, drop, or bubble volume as well as the radius of curvature can all be obtained simultaneously.

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2006

Colloid Stability

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Method for direct measurement of the film tension of black foam films at various capillary pressures

Cited by 19 publications

References 7 publications

Contact angles of protein black foam films under dynamic and equilibrium conditions

Contact angles of protein black foam films under dynamic and equilibrium conditions

Film Tension and Film Rupture of Alkanes at the Air−Water Interface Using Axisymmetric Drop Shape Analysis

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