Thermodynamics of Adsorption and Gibbsian Distance Parameters in Two- and Three-Phase Systems

Good, Robert J.

doi:10.1351/pac197648040427

Cited by 24 publications

(17 citation statements)

References 15 publications

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“…[1][2][3][4]6 Let z i and z j be the locations for the dividing surface that make ⌫ i ϭ0 and ⌫ j ϭ0, respectively, and, in standard notation, let ⌫ i( j) be the adsorption ⌫ i when the dividing surface is chosen to be at z j , where ⌫ j ϭ0. [1][2][3][4]6 Let z i and z j be the locations for the dividing surface that make ⌫ i ϭ0 and ⌫ j ϭ0, respectively, and, in standard notation, let ⌫ i( j) be the adsorption ⌫ i when the dividing surface is chosen to be at z j , where ⌫ j ϭ0.…”

Section: Introductionmentioning

confidence: 99%

“…In a one-component system, or in a c-component system at fixed 3 ,..., cϩ1 , there is only one independently variable i , say 1 . Then from Eqs.…”

Section: Introductionmentioning

confidence: 99%

“…The dihedral angles between interfaces are the contact angles, which we also call ␣, ␤, and ␥, with ␣ϩ␤ϩ␥ϭ2. We ask what those loci are, and what geometrical infor-mation is contained in ⌳ 1 (2,3) , the linear adsorption of component 1 in a frame of reference in which ⌳ 2 ϭ⌳ 3 ϭ0; i.e., when the contact line is chosen to be at the intersection of the curves ⌳ 2 ϭ0 and ⌳ 3 ϭ0. 1.…”

Section: Introductionmentioning

confidence: 99%

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Geometric view of the thermodynamics of adsorption at a line of three-phase contact

Djikaev

Widom

2004

The Journal of Chemical Physics

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We consider three fluid phases meeting at a line of common contact and study the linear excesses per unit length of the contact line (the linear adsorptions Lambda(i)) of the fluid's components. In any plane perpendicular to the contact line, the locus of choices for the otherwise arbitrary location of that line that makes one of the linear adsorptions, say Lambda(2), vanish, is a rectangular hyperbola. Two of the adsorptions Lambda(2) and Lambda(3) then both vanish when the contact line is chosen to pass through any of the intersections of the two corresponding hyperbolas Lambda(2)=0 and Lambda(3)=0. There may be two or four such real intersections. It is found most surprisingly, and confirmed in a numerical example, that Lambda(1(2,3)), the adsorption of component 1 in a frame of reference in which the adsorptions Lambda(2) and Lambda(3) are both 0, depends on which intersection of the hyperbolas Lambda(2)=0 and Lambda(3)=0 is chosen for the location of the contact line. This implies that what had long been taken to be the line analog of the Gibbs adsorption equation is incomplete; there must be additional, previously unanticipated terms in the relation, consistent with the invariance of the line tension to choice of location of the contact line. It is then not Lambda(1(2,3)) by itself but a related expression containing it that must be invariant, and this invariance is also confirmed in the numerical example. The presence of the additional terms in the adsorption equation is further confirmed and their origin clarified in a mean-field density-functional model. The supplemental terms vanish at a wetting transition, where one of the contact angles goes to 0.

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Section: Introductionmentioning

confidence: 99%

“…In a one-component system, or in a c-component system at fixed 3 ,..., cϩ1 , there is only one independently variable i , say 1 . Then from Eqs.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Geometric view of the thermodynamics of adsorption at a line of three-phase contact

Djikaev

Widom

2004

The Journal of Chemical Physics

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“…A geometric method was reported by Everett in a very elegant manner [7,8]. those of Good [9][10][11][12], Motomura [13,14] and Vernov and Lopatkin [15][16][17]. those of Good [9][10][11][12], Motomura [13,14] and Vernov and Lopatkin [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Algebraic and geometric interpretations of adsorption excess quantities

Király¹,

Dékány²

1988

Colloid & Polymer Sci

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The algebraic methods of Hansen and Goodrich and the geometric methods of Motomura, Good and Everett were applied to define and investigate adsorption excess quantities at a solid/binary liquid interface. Both single-plane and two-plane geometric constructions were found to be consistent with the algebraic method. Relations between the relative, molar reduced and volumetric reduced areal excess concentrations and the amounts of components actually present in the interfacial layer are discussed.

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“…In spite of its sound thermodynamic basis, the ambiguities in the physical meaning of the concepts used by Gibbs have led to additional interpretations by others (Alberty, 1995;Ikeda, 1982;Mitropoulos, 2008) and raised conflict of ideas between various groups, examples of which are the disagreement between Good (Good, 1976(Good, , 1982a and Motomura (Motomura, 1986) and that of Miller (Fainerman et al, 2002b, 2000) with Aratono et. al.…”

Section: Arguments About the Validity Of Gaimentioning

confidence: 99%

Molecular insights of adsorption and structure of surfactants and inorganic ions at fluid – liquid interfaces

Shahir¹

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Traditional approaches to studying fluid -liquid interfaces include the macroscopic measuring of interfacial properties such as surface tension and matching the collected data against adsorption models. This method is capable of producing valuable data about the thermodynamics of adsorption and has been widely used by the community to extract information about the adsorption of thousands of different surface-active molecules. Nonetheless, this methodology cannot produce any molecular-level information about the microscopic structure of adsorption layers and interfaces.As a result, the molecular origins of many interfacial phenomena remained unknown until the advent of surface-sensitive techniques such as computer simulation and non-linear spectroscopy.The new insights provided by these methods have challenged the traditional views about the origins of some interfacial phenomena and promise modification of classical theories which were developed to explain these phenomena.In general, this thesis aims to study the interfacial structure and adsorption of ionic surfactants, some surface-active alcohols as model nonionic surfactants including, n-pentanol, methyl isobutyl carbinol (MIBC) and n-hexanol and inorganic salts including LiCl, NaCl and CsCl at both microscopic and macroscopic levels. The employed methodology involves a combination of traditional adsorption modelling with some macroscopic measurements and sum frequency generation (SFG) spectroscopy, which is capable of distinguishing between bulk and interfacial molecules. Using SFG spectroscopy, the interfacial structure of adsorption layers and the composition of interfaces were investigated in detail and independently of the bulk solution.Specifically, the surface saturation of solutions of MIBC was identified directly using SFG spectroscopy and was then compared to equilibrium surface tension data to find that surface tension surprisingly continued to decrease even after full surface saturation. This is in contradiction to the traditional view that all surfactants adsorb at the outermost adsorption monolayer. Because of the limited surface area of the topmost adsorption monolayer, its full saturation is considered as the end of the adsorption process. This view is based on the notion of Gibbs dividing plane, which is usually taken as being equal to the physical adsorption monolayer in a surfactant solution. The postsaturation surface tension decrease, therefore, cannot be explained by the Gibbs convention. A different adsorption geometry, which considers the under-monolayer adsorption of alcohols, was proposed based on the Guggenheim extended interface model. In Chapter 5, a recent controversy about the applicability of the famous Gibbs adsorption isotherm to the analysis of surface tension data was addressed with regards to the new concept of under-monolayer adsorption. The results showed that the linearity of a surface tension plot is not necessarily indicative of a fully saturated ii surface. The same adsorption geometry was also proposed for t...

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Thermodynamics of Adsorption and Gibbsian Distance Parameters in Two- and Three-Phase Systems

Abstract: Abstract-In a multicomponent, 2-phase system, the Gibbs dividing surfaces for the respective components are separated by characteristic distances, A, = 17/iXc5.

Cited by 24 publications

References 15 publications

Geometric view of the thermodynamics of adsorption at a line of three-phase contact

Geometric view of the thermodynamics of adsorption at a line of three-phase contact

Algebraic and geometric interpretations of adsorption excess quantities

Molecular insights of adsorption and structure of surfactants and inorganic ions at fluid – liquid interfaces

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