Supramolecular gels are widely studied for their interest in many applications ranging from food, cosmetic thickeners, and textile fibers to support matrices for drug delivery and tissue replacement. In recent years many works have been published aimed at investigating the fundamental aggregate structures in the gels and the intermolecular interactions stabilizing them which turns out to be extremely important for the applications. As reported in many published results, pure bile salts and cationic analogues have generally remarkable gelling properties. Starting from this knowledge, anionic and cationic derivatives containing aromatic moieties were synthesized in order to enhance their gelling ability by the formation of π-π stacking. In addition catanionic mixtures were prepared to exploit the effect of electrostatic attraction in the gel formation [1]. The results show that only the cationic derivative form gels as a pure surfactant solution. However the presence of favorable electrostatic interactions allows to get more efficient gels in catanionic mixtures both in terms of mechanical properties and minimum gelation concentration. Compact gels with total surfactant concentration of 0,05% w/v were obtained. Therefore this work suggests that catanionic mixtures can be used to enhance the gelator efficiency of molecules, constituting an information of quite general importance in the preparation of molecular gels. Moreover, beside the high gelation efficiency, these catanionic mixtures could also provide gels of fibrils with tunable charge, which could allow the regulation of their interaction with cells or active molecules and macromolecules, further widening their applicative range.
[1] M. C. di Gregorio, N. V. Pavel, J. Miragaya, A. Jover, F. Meijide, J. Vázquez Tato, V. H. Soto Tellini, L. Galantini,
Langmuir,
2013, 29, 12342-12351
mariachiara.digregorio@uniroma1.it
