On the Thermodynamics of Surface Systems

Eriksson, Jan Christer

doi:10.1002/9780470143520.ch3

Cited by 18 publications

(5 citation statements)

References 13 publications

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“…More elaborate models for surface tensions of mixtures are available; we have tested one in which molecular interactions are accounted for by a Flory parameter [17] and found it equivalently described our frothing data. Therefore, our analysis is not model-dependent and in the following we use the simple approximation of eq.…”

Section: Fig 1: Surface Tensions Of Decane/toluene (Red) and Octane/mentioning

confidence: 99%

Understanding Frothing of Liquid Mixtures: A Surfactantlike Effect at the Origin of Enhanced Liquid Film Lifetimes

et al. 2020

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Section: Fig 1: Surface Tensions Of Decane/toluene (Red) and Octane/mentioning

confidence: 99%

Understanding Frothing of Liquid Mixtures: A Surfactantlike Effect at the Origin of Enhanced Liquid Film Lifetimes

et al. 2020

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“…2020, 2021), the length varies with mixture composition and reaches a maximum at a composition depending on the species at stake; its value is a few tenths of nanometres at most for the mixtures investigated herein. The length also depends on the surfaces of the molecules at the interface, which are poorly known quantities since they are not measured but extrapolated from other properties (Eriksson 1964; Santos & Reis 2014). The value of is particularly difficult to determine in mixtures of molecules of very different sizes.…”

Section: Thickness-dependent Surface Tension Of Binary Mixturesmentioning

confidence: 99%

“…We have recently shown that the phenomenon at the origin of the longer bubble lifetimes in binary mixtures is the difference of molecular concentrations between the bulk and the interfaces, when the two liquids have different surface tensions (Tran et al 2020(Tran et al , 2021. Actually, it has been established long ago that, in mixtures, the molecules with the smallest surface energy are more concentrated at the interface than in the bulk (Butler 1932;Prigogine & Marechal 1952;Eriksson 1964). We have demonstrated that the species with the lowest surface tension can thus play a surfactant-like role for the other species.…”

Section: Introductionmentioning

confidence: 99%

“…2020, 2021). Actually, it has been established long ago that, in mixtures, the molecules with the smallest surface energy are more concentrated at the interface than in the bulk (Butler 1932; Prigogine & Marechal 1952; Eriksson 1964). We have demonstrated that the species with the lowest surface tension can thus play a surfactant-like role for the other species.…”

Section: Introductionmentioning

confidence: 99%

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Mechanisms ruling the lifetimes of films of liquid mixtures

et al. 2022

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Foams and bubbles formed in liquid mixtures have lifetimes longer by several orders of magnitude than in pure liquids of similar viscosities. We have shown recently that this effect results from slight differences in molecular concentrations between bulk and surfaces, which give rise to a thickness-dependent surface tension of liquid films. We present a quantitative description of the enhanced stability of liquid films in binary mixtures, based on experimental data and theoretical analysis. Experiments were performed with mixtures of different natures and compositions: foams of stationary heights were obtained by continuous injection of gas, on one hand, and single bubbles were swollen under the surface of a liquid bath, on the other hand. Remarkably, the lifetimes measured in both experiments exhibit the same variations with mixture composition, and follow a power law with the microscopic length that characterises the amplitude of the thickness-dependent surface tension. In addition, the lifetimes vary with the squared film thicknesses at the onset of bursting. We suggest that two stages occur between the birth of liquid films and their rupture. We show how the thickness-dependent surface tension allows an equilibrium shape to be reached at the end of a first stretching stage. We give an analytical description of this shape, which is fully consistent with experimental findings. We suggest a possible mechanism for final rupture of the film, and discuss it in light of existing theoretical predictions. Finally, we compare the properties of liquid mixtures and surfactant solutions, and in particular their surface rheology.

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“…Considering a physical planar surface phase 15 of molecular components A and B at fixed temperature T and pressure p that is in thermodynamic equilibrium with an underlying liquid phase, the differential of the surface-phase Gibbs energy is where G stands for Gibbs energy, S for entropy, V for volume, γ for surface tension, A for surface area, and μ i and n i for chemical potential and the amount of the substance, respectively, of component i = A, B. The superscript “s” denoting the surface phase is only attached to properties whose equilibrium values are different in both phases.…”

Section: Butler Equationmentioning

confidence: 99%

Examination of the Butler Equation for the Surface Tension of Liquid Mixtures

Santos

Reis

2021

ACS Omega

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The classical Butler equation used to describe surface tension and the surface composition of liquid mixtures is revisited. A straightforward derivation is presented, separating basic chemical thermodynamics and assumptions proper to Butler’s model. This model is shown to conceal an approximation not recognized by other researchers. The shortcoming identified consists of not allowing surface standard values to vary with surface tension by virtue of the changing composition. A more rigorous equation is derived and shown to yield the Butler equation in case of incompressible surface phases. It is concluded that the Butler equation slightly overestimates ideal surface tensions. Butler’s surface-phase concentrations of the surface-active component are also slightly overestimated in the surface-active component dilute range, being just underestimated at higher concentrations. Despite this, Butler’s model stands as a very good standard due to its versatility.

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On the Thermodynamics of Surface Systems

Cited by 18 publications

References 13 publications

Understanding Frothing of Liquid Mixtures: A Surfactantlike Effect at the Origin of Enhanced Liquid Film Lifetimes

Understanding Frothing of Liquid Mixtures: A Surfactantlike Effect at the Origin of Enhanced Liquid Film Lifetimes

Mechanisms ruling the lifetimes of films of liquid mixtures

Examination of the Butler Equation for the Surface Tension of Liquid Mixtures

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