Die Kapillarkurve der höheren Fettsäuren und die Zustandsgleichung der Oberflächenschicht

Frumḳin, A.

doi:10.1515/zpch-1925-11629

Cited by 617 publications

(111 citation statements)

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“…Therefore the adsorption coefficient K i in (la) and (lb) varies throughout the surfactant concentration range of interest (i.e., from zero to CMC). In addition to the Gibbs equation, other isotherm models [e.g., Szyszkowski, 1908; Frumkin, 1925] were suggested to correlate the concentration of surfactant in the bulk aqueous phase with the surface excess and the surface or interfacial tension. These equations allow the conversion of the surface tension data to estimate a surface adsorption isotherm, subject to several assumptions, depending on the experimental conditions.…”

Section: Surface Tension Measurementmentioning

confidence: 99%

Determination of effective air‐water interfacial area in partially saturated porous media using surfactant adsorption

Kim¹,

Rao²,

Annable³

1997

Water Resources Research

161

188

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Abstract. The effective specific air-water interfacial area (•i) in a sand-packed column was measured at several water saturations (Sw) using a surface-reactive tracer (sodium dodecylbenzene sulfonate (SDBS)) and a nonreactive tracer (bromide). Miscible displacement experiments were conducted under steady water flow conditions to quantify the retardation of SDBS resulting from its adsorption onto the air-water interface in a sand-packed column. A consistent trend of increased retardation of SDBS compared with the nonreactive tracer, bromide, was observed with decreasing S w. The data for air-water surface tension measured at various SDBS concentrations were interpreted using the Gibbs model to estimate the required adsorption parameters. The retardation factors (Rt) for SDBS breakthrough curves were then used in combination with the estimated SDBS adsorption coefficient to calculate the •i values at different Sw. For the range of experimental conditions employed in this study, the retardation factor for SDBS ranged from R t = 1.07 at Sw = 1.00 (R t > 1 due to SDBS sorption on sand) to R t = 3.44 at Sw = 0.29 (which corresponds to •i = 46 cm2/cm3). These values are in agreement with theoretical predictions and recently published data. Improvements needed to overcome the experimental limitations of the presented method are also discussed.

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Section: Surface Tension Measurementmentioning

confidence: 99%

Determination of effective air‐water interfacial area in partially saturated porous media using surfactant adsorption

Kim¹,

Rao²,

Annable³

1997

Water Resources Research

161

188

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“…where the surface pressure Π is the work per unit area which must be done to compress the monolayer. This equation of state can be derived from a regular solution theory for a monolayer (Guggenheim 1952;Defay & Prigogine 1966) or from an adsorption-kinetic approach (Frumkin 1925). (In (3), the terms accounting for surfactant interaction have been neglected.)…”

Section: Introductionmentioning

confidence: 99%

Insoluble surfactants on a drop in an extensional flow: a generalization of the stagnated surface limit to deforming interfaces

Pawar²,

1999

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A drop in an axisymmetric extensional ow is studied using boundary integral methods to understand the effects of a monolayer-forming surfactant on a strongly deforming interface. Surfactants occupy area, so there is an upper bound to the surface concentration that can be adsorbed in a monolayer, Γ∞. The surface tension is a highly nonlinear function of the surface concentration Γ because of this upper bound. As a result, the mechanical response of the system varies strongly with Γ for realistic material parameters. In this work, an insoluble surfactant is considered in the limit where the drop and external fluid viscosities are equal.For Γ<Γ∞, surface convection sweeps surfactant toward the drop poles. When surface diffusion is negligible, once the stable drop shapes are attained, the interface can be divided into stagnant caps near the drop poles, where Γ is non-zero, and tangentially mobile regions near the drop equator, where the surface concentration is zero. This result is general for any axisymmetric fluid particle. For Γ near Γ∞, the stresses resisting accumulation are large in order to prevent the local concentration from reaching the upper bound. As a result, the surface is highly stressed tangentially while Γ departs only slightly from a uniform distribution. For this case, Γ is never zero, so the tangential surface velocity is zero for the steady drop shape.This observation that Γ dilutes nearly uniformly for high surface concentrations is used to derive a simplified form for the surface mass balance that applies in the limit of high surface concentration. The balance requires that the tangential flux should balance the local dilatation in order that the surface concentration profile will remain spatially uniform. Throughout the drop evolution, this equation yields results in agreement with the full solution for moderate deformations, and underscores the dominant mechanism at high deformation. The simplified balance reduces to the stagnant interface condition at steady state.Drop deformations vary non-monotonically with concentration; for Γ<Γ∞, the reduction of the surface tension near the poles leads to higher deformations than the clean interface case. For Γ near Γ∞, however, Γ dilutes nearly uniformly, resulting in higher mean surface tensions and smaller deformations. The drop contribution to the volume averaged stress tensor is also calculated and shown to vary non-monotonically with surface concentration.

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“…Therefore, we decided to use a simpler thermodynamic model, which considers the adsorption of the surfactant molecules at the interface while the oil molecules are passively embedded in the oleophilic moiety of the surfactant adsorption layers. Hence, we use two classical adsorption models, the one developed by Frumkin [23] and the reorientation model proposed by Fainerman et al [24]. Via a best fit procedure, the experimental equilibrium and kinetic interfacial tension data were directly compared with the calculated data and thus the values for the characteristic parameters for the two theoretical models obtained.…”

Section: Theorymentioning

confidence: 99%

Adsorption of Equimolar Mixtures of Cationic and Anionic Surfactants at the Water/Hexane Interface

Mucic

Škrbić

Bučko

et al. 2020

Colloids and Interfaces

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In mixed solutions of anionic and cationic surfactants, called catanionics, ion pairs are formed which behave like non-ionic surfactants with a much higher surface activity than the single components. In equimolar mixtures of NaCnSO4 and CmTAB, all surface-active ions are paired. For mixtures with n + m = const, the interfacial properties are rather similar. Catanionics containing one long-chain surfactant and one surfactant with medium chain length exhibit a strong increase in surface activity as compared with the single compounds. In contrast, catanionics of one medium- and one short chain surfactant have a surface activity similar to that of the medium-chain surfactant alone. Both the Frumkin model and the reorientation model describe the experimental equilibrium data equally well, while the adsorption kinetics of the mixed medium- and short-chain surfactants can be well described only with the reorientation model.

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Die Kapillarkurve der höheren Fettsäuren und die Zustandsgleichung der Oberflächenschicht

Cited by 617 publications

References 0 publications

Determination of effective air‐water interfacial area in partially saturated porous media using surfactant adsorption

Determination of effective air‐water interfacial area in partially saturated porous media using surfactant adsorption

Insoluble surfactants on a drop in an extensional flow: a generalization of the stagnated surface limit to deforming interfaces

Adsorption of Equimolar Mixtures of Cationic and Anionic Surfactants at the Water/Hexane Interface

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