Physical organogels have attracted considerable interest in recent years because of the great diversity of molecular structures that have been found to form such gels.¹ While gel formation in water by synthetic and biopolymers is a well-documented phenomenon,² examples of low molecular mass gelators of aqueous solutions are less common.³ We have recently discovered that simple cationic and neutral molecules with a bile acid backbone can form stable, transparent and thermo-reversible gels in aqueous media at remarkably low concentrations. From fluorescence experiments we find evidence that the aggregation process leading to gelation generates highly hydrophobic pockets in the predominantly aqueous media. It has also been found that the gelation process can be visualized by a color change. Some of our recent results, including our efforts to carry our reactions in the hydrophobic pockets of these gels will be discussed in this short presentation.

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2. Guenet, J.M. Thermoreversible Gelation of Polymers and Biopolymers; Academic Press, New York, 1992

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