INTERCALATION IN NOVEL ORGANOGELS WITH A STACKED PHENOL MICROSTRUCTURE

In nonpolar solvents, dry reversed micelles of the twin-tailed anionic surfactant sodium bis(2-ethylhexyl) sulfosuccinate (AOT) transform into a class of organogels upon the addition of suitable phenols. The gels are novel in that very small quantities of these low molecular weight solutes are sufficient to cause gelation. Hydrogen-bonding interactions between phenols and the head group of AOT form the basis for such gels. The gel-liquid transition is sharply defined and occurs over a very narrow temperature range when the gel is warmed or when trace amounts of moisture are absorbed. Evidence suggests that the underlying molecular architecture of these gels consists of strands of stacked and motionally restricted phenol molecules, with the surfactant adsorbed externally. We present further supporting evidence in this report and show that these gels can be doped with substantial quantities of a second species, leading to the formation of mixed gels. NMR evidence indicates that some of these dopants stack into the gel matrix by ''intercalation'' into the motionally restricted region of the aromatic strand. Factors such as the molecular shape and proton donor strength (acidity) that determine whether or not a dopant is intercalated are examined.