An organogel formed by the addition of selected dihydroxynaphthalenes to AOT inverse micelles

A clear organogel is formed upon the addition of small quantities of 2,6-dihydroxynaphthalene (2,6-DHN) to sodium bis(2-ethylhexyl)sulfosuccinate (AOT) inverse micelles in isooctane. The phenomenon of organogel formation appears to be generally applicable for dihydroxynaphthalenes with hydroxyl groups at opposite ends of the molecule. The gel forms at concentrations of 2,6-DHN as low as 0.002 M and AOT/2,6-DHN molar ratios in the range of 50-70. The gel displays the photoluminescence characteristics of the dopant aromatic species. NMR characterizations of the gel structure reveal significant restrictions on the motion of 2,6-DHN on the NMR time scale. FTIR reveals the presence of hydrogen-bonding interactions between 2,6-DHN and AOT that may play a significant role in gel formation. A microstructure for the gel is proposed wherein 2,6-DHN bridging between micelles leads to rigidification and the formation of a novel partially frozen micellar structure.