Structure of the microemulsion/oil/water interfaces

Beaglehole, D.; Clarkson, M. T.; Upton, A.M.C.

doi:10.1016/0021-9797(84)90042-0

Cited by 12 publications

(7 citation statements)

References 6 publications

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“…Figure 4 shows the experimental values of 1]MO and 1]MW. There are two small differences with the results of Beaglehole et al [13]. 1) Our positive peak values of 1] are twice as big.…”

Section: Organic Phase-aqueous Phase Interface (Ow) -contrasting

confidence: 77%

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Measurement of the rigidity coefficient of a surfactant layer and structure of the oil or water microemulsion interface

Meunier

1985

J. Phyique Lett.

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We first deduce the rigidity coefficient K of a surfactant monolayer at the oil water interface from ellipsometric measurements. For our surfactant monolayer containing alcohol, we find unusually small values of K (K ~ kB T). We then study the oil microemulsion and water microemulsion interfaces, covered with the same film. On the microemulsion side of the film we find a perturbed zone, the thickness of which is comparable with the size of the structure in the bulk. The experimental results suggest that at ultralow surface tension, the recently proposed picture of an open interface, is quite valid

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“…Figure 4 shows the experimental values of 1]MO and 1]MW. There are two small differences with the results of Beaglehole et al [13]. 1) Our positive peak values of 1] are twice as big.…”

Section: Organic Phase-aqueous Phase Interface (Ow) -contrasting

confidence: 77%

“…We will furthermore present some extra information about the structure of the OM and WM interfaces. Though our ellipticity measurements are similar (but more complete) to previous ones on these microemulsions systems [13], some differences will be discussed later.…”

Section: Introductionsupporting

confidence: 69%

Measurement of the rigidity coefficient of a surfactant layer and structure of the oil or water microemulsion interface

Meunier

1985

J. Phyique Lett.

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“…This is not dramatic in the case of the reflectivity where this cut-off appears in a logarithmic term. The value of the cut-off is very important in ellipsometry and roughness was mentioned but could never be exactly taken into account in the analysis of experimental studies [7][8][9] except in the case of a surfactant monolayer [10,11]. In this case a natural cut-off is introduced by the rigidity of the monolayer and ellipsometry is then a good technique to measure this rigidity.…”

mentioning

confidence: 99%

Liquid interfaces : role of the fluctuations and analysis of ellipsometry and reflectivity measurements

Meunier¹

1987

J. Phys. France

174

119

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HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Liquid interfaces : role of the fluctuations and analysis of ellipsometry and reflectivity measurements J. MeunierTo cite this version:J. Meunier. Liquid interfaces : role of the fluctuations and analysis of ellipsometry and reflectivity measurements.Résumé. 2014 Nous montrons que les difficultés qui apparaissent dans l'interprétation des propriétés optiques des interfaces liquides disparaissent quand on développe une théorie prenant en compte le couplage entre les modes thermiques de fluctuations de l'interface. Une telle théorie permet de déduire les propriétés optiques des interfaces critiques en ne prenant en compte que des paramètres macroscopiques. dont aucun n'est ajustable. Lorsque les interfaces, tels que les monocouches de surfactants, présentent une rigidité, cette théorie permet d'extraire un coefficient de rigidité à toute échelle des mesures d'ellipsométrie. La longueur de persistance déduite de ce coefficient de rigidité est en accord avec les structures de phases observées.Abstract. 2014 It is shown that the difficulties which appear in the interpretation of optical properties of liquid interfaces disappear when we develop a coupled mode theory of thermal interfacial fluctuations. First, we are able to calculate the optical properties of critical interfaces with only macroscopic non adjustable parameters. Secondly, we can deduce the rigidity constant at any length scale of monolayers from ellipsometric measurements. The persistence lengths of monolayers that we deduce are in perfect agreement with the phase structures we observe.

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“…ii) the case of a narrow interface associated with a relatively large interfacial tension ( ~ 10-2 dyne/cm). In this case, an ellipsometry experiment [27] has shown that a Langmuir film probably separates the microemulsion from either the oil phase or the water phase and that a thin wetting layer of the third phase exists between the Langmuir film and the microemulsion.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, the local structure of the o/m and w/m interfacial regions is little known. Surface tensions [26] and ellipsometry measurements [27] have evidenced two extreme cases : i) the case of a thick diffuse critical interface associated with a very small interfacial tension (-10 -5 dyne/cm) ;…”

Section: Introductionmentioning

confidence: 99%

Deviations from the spontaneous curvature in surfactant films : effects on the second virial coefficient and interfacial properties of the microemulsions

Auvray

1985

J. Phyique Lett.

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One evaluates the contributions of the surfactant interfacial film bending energy first to the attractive interactions between droplets in dilute microemulsions and second to the interfacial tensions in triphasic Winsor systems far from the critical points. (1) In a dilute water in oil microemulsion where the water droplet curvature (defined as positive) is slightly larger than the interfacial film's spontaneous curvature C0, a possible fluctuation at thermodynamic equilibrium is the fusion of two droplets in a dimer of low curvature energy. This process gives an attractive contribution to the droplet second virial coefficient which is in good agreement with certain experimental observations. (2) The interface between a microemulsion and an excess phase, oil for example, is either closed by a flat Langmuir type surfactant film, in which case a wetting water layer separates the film and the microemulsion, or open, i.e. traversed by oil pores. The microemulsion surfactant film curvature is on average directed towards oil in the first case and towards water in the second case. We show by using the microemulsion random structure model proposed by de Gennes that, in the Winsor triphasic systems, the water/microemulsion interface evolves from the case « open » to the case « closed » and the oil/microemulsion from the case « closed » to the case « open », when the water salinity, i.e. C0, increases. When | C0 | is small, the two interfaces are « open » and the difference between the surface tensions of the two interfaces is proportional to C0. One recovers the result that this difference vanishes at the optimal salinity (C0 = 0)

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Structure of the microemulsion/oil/water interfaces

Cited by 12 publications

References 6 publications

Measurement of the rigidity coefficient of a surfactant layer and structure of the oil or water microemulsion interface

Measurement of the rigidity coefficient of a surfactant layer and structure of the oil or water microemulsion interface

Liquid interfaces : role of the fluctuations and analysis of ellipsometry and reflectivity measurements

Deviations from the spontaneous curvature in surfactant films : effects on the second virial coefficient and interfacial properties of the microemulsions

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