(408d) A New Class of Self-Assembled Organogels Induced by Bile Salts at Submillimolar Concentrations

We report a new class of self-assembled organogels obtained by mixing two amphiphilic molecules, viz. the anionic surfactant (AOT) and a bile salt, sodium deoxycholate (SDC). When added to solvents such as cyclohexane and n-decane, AOT by itself forms low viscosity solutions containing reverse spherical micelles, while SDC is insoluble in these solvents. However, when ca. 5 mM of AOT in cyclohexane is mixed with trace amounts (< 1 mM) of SDC, the result is an elastic gel that holds its weight upon inverting the vial. Interestingly, the same bile salt is also capable of gelling water over a certain range of pH, while other related bile salts do not gel water nor do they induce organogels. We will propose a tentative model for the structure of AOT-SDC organogels, highlighting the role played by the bile salt in organogel formation.