Extension of the Vibrating Jet Method for Surface Tension Measurement to Jets of Non-uniformVelocity Profiles

Hansen, Robert S.; Purchase, Mary E.; Wallace, Terry C.; Woody, Robert W.

doi:10.1021/j150560a016

Cited by 41 publications

(6 citation statements)

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“…Oscillation techniques can resolve time scales of the order of milliseconds to several minutes. Some of the methods involving convection are: Oscillating jet technique (Defay and Hommelen, 1958;Hansen et al, 1958;Thomas and Potter, 1975)…”

mentioning

confidence: 99%

Diffusion‐controlled surfactant adsorption studied by pendant drop digitization

1990

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Pendant drop tensiometry enhanced by video-image digitization is shown to be a useful tool for the experimental measurement of the relaxation in interfacial tension due to the adsorption of surfactant at a fluid interface. Using this method, profiles of the relaxation in surface tension of a diffusion-controlled, nonionic polyethoxy surfactant were measured. A diffusion coefficient was computed by comparing these profiles with numerical solutions of the bulk surfactant diffusion equation and a Frumkin equilibrium adsorption isotherm. This comparison was made for the entire relaxation period. This method establishes a more reproducible diffusion coefficient than current techniques that utilize only the short-or long-time parts of the relaxation spectrum. In addition, lower bounds on the kinetic constants for the sorption process are inferred for the polyethoxy surfactant used by comparing numerical solutions of mixed diffusion and surface kinetic transfer with the diffusion-limited result.

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mentioning

confidence: 99%

Diffusion‐controlled surfactant adsorption studied by pendant drop digitization

1990

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“…First, if the experimental data are extrapolated back to zero surface concentration (i.e., a freshly generated surface), the intercept does not correspond to t = 0 but to a slightly later time. As discussed above, the emergent surface undergoes rapid expansion as it accelerates from a speed of zero to close to the mean jet speed . Even though adsorption is taking place, the surface coverage remains very small until the end of this rapid expansion phase.…”

Section: Resultsmentioning

confidence: 95%

“…This method of calculating the surface age is only approximate, because it assumes that the jet has a uniform flow profile from the moment it leaves the orifice and that the diameter of the jet remains constant. In practice, the no-slip condition within the nozzle results in deviations from plug flow, and the jet profile relaxes gradually to a uniform profile once it leaves the nozzle. − Balancing of the momentum fluxes during this process results in a slight thinning of the jet . For the purpose of this proof-of-principle experiment, the assumption of plug flow will suffice, but for more accurate work, it will be necessary to simulate, or measure, the actual flow profile in the jet.…”

Section: Methodsmentioning

confidence: 99%

Measurements of the Adsorption Kinetics of a Cationic Surfactant in a Liquid Jet by Ellipsometry

Hutchison¹,

Klenerman²,

Manning-Benson³

et al. 1999

Langmuir

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A new technique for the study of the kinetics of adsorption of surfactants at the air−water interface on the 1−20 ms time scale is described. Ellipsometric measurements were performed directly on the surface of a high-speed jet containing a solution of hexadecyltrimethylammonium bromide (CTAB). The coefficient of ellipticity was converted to surface concentration with the aid of neutron reflection data obtained previously on an overflowing cylinder. By this method, the surface concentration in the jet can be measured with a precision of 5% of a monolayer. An approximate measure of the interfacial age was obtained from the speed of the jet. The experimental data were tested against theoretical predictions and found to be consistent with diffusion-limited adsorption within the error of the experiment. Experimental data obtained at different jet speeds were in good agreement, suggesting that Marangoni effects did not play an important role.

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“…[11], [12], and [13] that the measurements φ 1 (z) and φ 2 (z) atz only appear in the calculation of surface tension σ 1 (T ) through their product in the expression [11] for axial velocity v. Combining Eqs. [11] and [16] gives axial velocity as an explicit function of surface age,…”

Section: Computation Of Surface Tensionmentioning

confidence: 99%