scholarly journals Surface tension of flowing soap films

2018 ◽  
Vol 841 ◽  
Author(s):  
Aakash Sane ◽  
Shreyas Mandre ◽  
Ildoo Kim
Keyword(s):  
Surface Tension ◽  
Film Thickness ◽  
Soap Solution ◽  
Soap Film ◽  
Soap Films ◽  
Adsorption Model ◽  
Asymptotic Value ◽  
Low Concentration ◽  
Two Parameters ◽  
Gibbs Elasticity

The surface tension of flowing soap films is measured with respect to the film thickness and the concentration of soap solution. We perform this measurement by measuring the curvature of the nylon wires that bound the soap film channel and use the measured curvature to parametrize the relation between the surface tension and the tension of the wire. We find that the surface tension of our soap films increases when the film is relatively thin or is made of soap solution of low concentration; otherwise, it approaches an asymptotic value of $30~\text{mN}~\text{m}^{-1}$. A simple adsorption model with only two parameters describes our observations reasonably well. With our measurements, we are also able to estimate the Gibbs elasticity of our soap film.

scholarly journals The dynamics of a viscous soap film with soluble surfactant

2001 ◽  
Vol 442 ◽  
pp. 387-409 ◽  
Author(s):  
JEAN-MARC CHOMAZ
Keyword(s):  
Film Thickness ◽  
Elastic Wave ◽  
Surfactant Concentration ◽  
Stokes Equations ◽  
Film Surface ◽  
Soap Film ◽  
Fluid Viscosity ◽  
Two Dimensional ◽  
Leading Order ◽  
Soap Films

Nearly two decades ago, Couder (1981) and Gharib & Derango (1989) used soap films to perform classical hydrodynamics experiments on two-dimensional flows. Recently soap films have received renewed interest and experimental investigations published in the past few years call for a proper analysis of soap film dynamics. In the present paper, we derive the leading-order approximation for the dynamics of a flat soap film under the sole assumption that the typical length scale of the flow parallel to the film surface is large compared to the film thickness. The evolution equations governing the leading-order film thickness, two-dimensional velocities (locally averaged across the film thickness), average surfactant concentration in the interstitial liquid, and surface surfactant concentration are given and compared to similar results from the literature. Then we show that a sufficient condition for the film velocity distribution to comply with the Navier–Stokes equations is that the typical flow velocity be small compared to the Marangoni elastic wave velocity. In that case the thickness variations are slaved to the velocity field in a very specific way that seems consistent with recent experimental observations. When fluid velocities are of the order of the elastic wave speed, we show that the dynamics are generally very specific to a soap film except if the fluid viscosity and the surfactant solubility are neglected. In that case, the compressible Euler equations are recovered and the soap film behaves like a two-dimensional gas with an unusual ratio of specific heat capacities equal to unity.

scholarly journals Tension grips the flow

2018 ◽  
Vol 846 ◽  
pp. 1-4
Author(s):  
M. M. Bandi
Keyword(s):  
Physical Chemistry ◽  
Fluid Dynamics ◽  
Surface Tension ◽  
Soap Solution ◽  
Dominant Role ◽  
Soap Film ◽  
Elastic Membrane ◽  
Two Dimensional ◽  
Interfacial Fluid ◽  
Interfacial Fluid Dynamics

Surface tension plays a dominant role in the formation and stability of soap films. It renders them both a quasi-two-dimensional fluid and an elastic membrane at the same time. The techniques for measuring the surface tension of the soap solution may very well apply to the static soap film, but how can the surface tension of a soap film be unintrusively measured, and what value would it assume? The answer, being at the intersection of physical chemistry, non-equilibrium physics and interfacial fluid dynamics, is not amenable to deduction via established methods. In a joint theoretical and experimental study, Sane et al. (J. Fluid Mech., vol. 841, 2018, R2) exploit elasticity theory to glean the answer through a simple, yet elegant framework.

3. On the Figures of Equilibrium of Liquid Films

1869 ◽  
Vol 6 ◽  
pp. 76-78
Author(s):  
David Brewster
Keyword(s):  
Soap Solution ◽  
Liquid Films ◽  
Vertical Position ◽  
Soap Bubble ◽  
Horizontal Position ◽  
Soap Films ◽  
Figures Of Equilibrium ◽  
New Phenomena

In repeating some of the experiments of Professor Plateau, described in seven interesting memoirs published in “The Transactions of the Belgian Academy,” and in prosecuting his own experiments on the colours of the soap-bubble, the author of this paper observed several new phenomena which may have escaped the notice of the Belgian philosopher.Professor Plateau has described and drawn the beautiful systems of soap-films, obtained by lifting from a soap solution a cube made of wires about one and a half inch long. This system is a polyhedron, composed of twelve similar films stretching from the wires, and united to a plane quadrangular film in the centre. When this vertical film was blown upon, M. Von Rees observed that it was reduced to a line, and then reproduced in a horizontal position, from which it could be blown again into a vertical position.

Bubble Entrapment in Sprayed Films

2014 ◽  
Author(s):  
A. Dalili ◽  
S. Chandra ◽  
J. Mostaghimi ◽  
H. T. Charles Fan ◽  
J. C. Simmer
Keyword(s):  
Surface Tension ◽  
Film Thickness ◽  
The Other ◽  
Bubble Motion ◽  
Sauter Mean Diameter ◽  
Glass Substrates ◽  
Buoyancy Forces ◽  
Mean Diameter ◽  
Imagej Software ◽  
Bubble Movement

A compressed air sprayer was used to spray model paint onto two glass substrates at the same time. Afterwards, one glass substrate was placed on a LED light source and still photographs were taken from the top using a DSLR camera with a timer system. The other substrate was put on a balance to record weight. Pictures and weight measurements were taken at 5 second intervals for 15 minutes. The sprayed film thickness was varied. The pictures were analyzed using ImageJ software. Bubble Count vs. Time, Sauter Mean Diameter (SMD) of Bubbles vs. Time as well as Weight vs. Time was plotted. It was seen that the pace of weight loss was faster for thinner films. The rate of bubble escape also depended on film thickness. It took a longer time for thicker films to lose the bubbles entrapped in them. In the first 30 seconds, large bubbles escaped due to buoyancy forces and afterwards surface-tension driven flows became dominant. There was also a lot of bubble movement in thicker films. The effect of gravity was studied as well. Gravity did not affect the bubble escape rate since a downward facing film had the same bubble count as an upward facing film confirming that bubble motion was not due to buoyancy forces alone. However, the SMD of bubbles in a downward facing film was larger than an upward facing film. Buoyancy is not a factor in bubble escape from the downward facing film and only surface-tension driven flows play a role.

Deformation characteristics of ultra-thin liquid film considering temperature and film thickness dependence of surface tension

2011 ◽  
Vol 17 (5-7) ◽  
pp. 983-990 ◽  
Author(s):  
Hiroshige Matsuoka ◽  
Koji Oka ◽  
Yusuke Yamashita ◽  
Fumihiro Saeki ◽  
Shigehisa Fukui
Keyword(s):  
Surface Tension ◽  
Film Thickness ◽  
Liquid Film ◽  
Thin Liquid Film ◽  
Thickness Dependence ◽  
Deformation Characteristics

Lielmezs–Herrick correlation for the temperature-dependent surface tension of hydrocarbons

2016 ◽  
Vol 30 (23) ◽  
pp. 1650154 ◽  
Author(s):  
Cuihua Zhang ◽  
Huili Yi ◽  
Jianxiang Tian
Keyword(s):  
Surface Tension ◽  
The Other ◽  
Temperature Dependent ◽  
Two Parameters ◽  
Two Parameter

In this paper, we analyzed the ability of Lielmezs–Herrick (LH) correlation for the temperature-dependent surface tension of 28 hydrocarbons. We found that compared with other published correlations, the original LH correlation stands well only for four fluids. By using new data in REFPROP database, we refitted the two parameters of LH correlation. Two sets values are obtained. One is the updated corresponding state LH correlation, which is fluid independent. The other is the two-parameter LH correlation, which is fluid dependent. We found that the former clearly improves the accuracy of the original LH correlation and the latter is the best among all of the correlations we know.

The detergent stress-cracking of polyethylene

1977 ◽  
Vol 352 (1671) ◽  
pp. 505-521 ◽  
Keyword(s):  
Surface Tension ◽  
Molecular Mass ◽  
Strain Hardening ◽  
Element Analysis ◽  
Stress Cracking ◽  
Plastic Materials ◽  
Environmental Stress Cracking ◽  
Tension Term ◽  
Plain Strain ◽  
Two Parameters

Many plastic materials fail under plain strain conditions by a process of micro-voiding in sheet-like structures known as crazes. These crazes are generally weak though their strength and stability may be improved in materials where orientation (strain) hardening occurs. Previously we have used finite element analysis, with a model consisting of an assembly of cylindrical holes, to study this type of plastic failure. With simple plasticity such models fail soon after yield, though they also would be stabilized by strain hardening. In this study we have introduced a surface-tension term which increases the resistance to plastic deformation. The effect is greatest when the holes are small and the yield strength of the material low. It is shown that when values of these two parameters representative of polyethylene at 50 °C are used surface tension should have a marked stabilizing effect for holes of < 25 nm radius. Even above this size range the failure stress can be affected at the 5-20 % level. An electron micrographic study was then carried out on polyethylenes cracked in the presence of an aqueous detergent (detergent stress cracking). It is shown that numerous small cavities and fibrils are formed on a scale small enough for the effect of surface tension to be significant. The rôle of the detergent in reducing surface tension and so promoting the fracture of polyethylene may therefore be understood. The marked influence of molecular mass on environmental stress cracking behaviour may be correlated with the greater development of orientation hardening at high strains with high molecular mass polymers. This increases the amount of plastic work preceding fracture and tends to stabilize a craze-like system.

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