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Symmetry and stability of AOT reverse micelles: Poisson–Boltzmann calculationsстатья
Статья опубликована в высокорейтинговом журнале
Статья опубликована в журнале из списка Web of Science и/или ScopusДата последнего поиска статьи во внешних источниках: 1 августа 2019 г.
- Авторы: Tovstun S.A., Razumov V.F.
- Журнал: Journal of Molecular Liquids
- Том: 275
- Год издания: 2019
- Издательство: Elsevier BV
- Местоположение издательства: Netherlands
- Первая страница: 578
- Последняя страница: 585
- DOI: 10.1016/j.molliq.2018.11.117
- Аннотация: Reverse micelles in sodium bis(2 ethylhexyl) sulfosuccinate (AOT) reverse microemulsions are known to be spherical over a wide range of compositions. Theoretically, the equilibrium shape of reverse micelles is determined by minimization of some free energy functional. We have recently shown that such a functional must contain contributions from the electrical double layer (EDL) formed in the water core due to surfactant dissociation and from the intrinsic curvature free energy of the surfactant monolayer. At that time, we applied this functional to the symmetrical shapes (sphere, cylinder, and lamella) and found that among them, the sphere may indeed be the most stable. However, for asymmetrical shapes no calculations have been carried out. Therefore, it is not immediately obvious to what extent asymmetry increases or decreases the free energy in our model: in particular, asymmetrical shapes, unlike the symmetrical ones, have non-zero electric field outside the polar core, which hypothetically, may significantly affect the solution. In this paper, we investigate the effect of asymmetry on the EDL free energy by performing detailed numerical calculations for the case of a reverse micelle having the shape of a prolate spheroid. The calculations show that the sphere or lamella always has a lower free energy than the prolate spheroid. By analyzing the solution for the prolate spheroid, we were able to make strong arguments that all asymmetrical shapes in our model are indeed thermodynamically unfavorable.
- Добавил в систему: Разумов Владимир Федорович