Solvent Selectivity in Helical/Linear Nanofiber-Derived Gelation Imparted by Chiral/Achiral Thixotropic Additive Molecules

Abstract

Among the functionalities exhibited by nanofibers, gelation/thixotropic properties arise from the solvent used. We clarified the selectivity of solvents for the gelation of nanofibers formed by diamide-based thixotropic additive molecules with two hydrocarbon chains. Chiral thixotropic additive molecules that form helical nanofibers tended to gel more efficiently in the same solvent compared to achiral straight nanofibers. These diamide groups with two hydrocarbon chains did not develop gelation ability in non-polar normal alkanes or solvents with low solubility owing to poor fiber development. In addition to that of the phenyl-based solvent, when the amount of the gelation solvent was increased, the entanglement density of the nanofibers decreased and consequently, the gelation ability tended to gradually decrease. These results support the conventional hypothesis, according to which the origin of solvent gelation is the efficient entrapment of solvent molecules into the tangled tissue of fibers.