Duvail Magali, Arleth Lise, Zemb Thomas, Dufrêche Jean-François
Institut de Chimie Séparative de Marcoule (ICSM), UMR 5257, CEA-CNRS-Université Montpellier 2-ENSCM, Site de Marcoule, Bâtiment 426, BP 17171, F-30207 Bagnols-sur-Cèze Cedex, France.
Niels Bohr Institute, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark.
J Chem Phys. 2014 Apr 28;140(16):164711. doi: 10.1063/1.4873357.
The thermodynamics and structural properties of flexible and rigid nonionic water/oil/surfactant microemulsions have been investigated using a two level-cut Gaussian random field method based on the Helfrich formalism. Ternary stability diagrams and scattering spectra have been calculated for different surfactant rigidities and spontaneous curvatures. A more important contribution of the Gaussian elastic constants compared to the bending one is observed on the ternary stability diagrams. Furthermore, influence of the spontaneous curvature of the surfactant points out a displacement of the instability domains which corresponds to the difference between the spontaneous and effective curvatures. We enlighten that a continuous transition from a connected water in oil droplets to a frustrated locally lamellar (oil in water in oil droplets) microstructure is found to occur when increasing the temperature for an oil-rich microemulsion. This continuous transition translated in a shift in the scattering functions, points out that the phase inversion phenomenon occurs by a coalescence of the water droplets.
基于赫尔弗里希形式主义，采用二级截断高斯随机场方法研究了柔性和刚性非离子水/油/表面活性剂微乳液的热力学和结构性质。针对不同的表面活性剂刚性和自发曲率，计算了三元相图和散射光谱。在三元相图上观察到高斯弹性常数比弯曲弹性常数有更重要的贡献。此外，表面活性剂自发曲率的影响指出了不稳定区域的位移，这对应于自发曲率和有效曲率之间的差异。我们发现，对于富含油的微乳液，当温度升高时，会发生从相连的油包水液滴到受挫的局部层状（油包水包油液滴）微观结构的连续转变。这种连续转变表现为散射函数的偏移，表明相转变现象是由水滴的聚并引起的。
