The author reported molecular organogels using N-alkylhydantoins as new low-molecular-weight gelators for the first time, and thixotropic mixed molecular organogels using a set of N-alkylhydantoin gelators with different alkyl chain lengths. These homologous compounds with different alkyl chains are found to form macroscopic crystals or solution states in polar solvents, but form homogeneous organogels in non-polar solvents, such as n-octane and squalane. Although there is no significant increase in the minimum gelation concentration of the mixed molecular gels using squalane as a solvent, these mixed molecular organogels show improved mechanical properties, especially in their thixotropic behavior, which is not observed in the single N-alkylhydantoin gels. Furthermore, they exhibit reversible thixotropic behavior with quick recovery of the gel state in a minute by quantitatively measuring dynamic viscoelasticity measurements of rheometry of mixed molecular gels. Based on the morphological observations of the xerogels, the self-assembling fibers of the gelators become finer, indicating an increase in the density of the mesh structure inside the gel, which could explain its thixotropic behavior. These thixotropic mixed molecular gels may be applicable to ointment base materials, because they are gelled with squalane oil.
Keywords: hydantoins; low-molecular-weight gelators; molecular gels; organogels; thixotropic behavior.