Are Micelles and Vesicles Chemical Equilibrium Systems?
-
Pier Luigi Luisi [1]
-
[1] ETH Zentrum, Switzerland
-
- Localización: Journal of chemical education, ISSN 0021-9584, Vol. 78, Nº 3, 2001, pág. 380
- Idioma: inglés
- Texto completo no disponible (Saber más ...)
-
Resumen
This paper focuses on whether and to what extent surfactant aggregates--in particular, vesicles--are chemical equilibrium systems. This is generally not clearly addressed in textbooks and often is approached in a confused manner in the specialized literature. I argue that, while micelles are fairly straightforward chemical equilibrium systems, the case of vesicles is more nebulous and plagued by the intrinsic ambiguity of terms such as "spontaneous", "metastable", and "non-equilibrium systems". I attempt to clarify and redefine these terms. Some of the most important criteria that discriminate between an equilibrium system and a non-equilibrium system are then outlined. Application of these criteria to vesicles does not always give unambiguous results, the main reason being that vesicles intrinsically cannot be assigned clearly to one category or the other. Several problems of vesicular systems can be qualitatively interpreted through the interplay of kinetic and thermodynamic factors.
