Formation mechanism of supramolecular hydrogels in the presence of l-phenylalanine derivative as a hydrogelator

A novel chiral hydrogelator, l-phenylalanine derivative can self-assemble in aqueous media at different pH values to form supramolecular hydrogels. The images of the FE-SEM indicate that different aggregates of TC18PheBu in morphology were formed, which further lead to the formation of spherical crystallites as observed by polarized optical microscope (POM). The FT-IR spectra of the supramolecular hydrogels reveal that intermolecular hydrogen-bonding and hydrophobic interactions are the driving forces for the self-assembly of TC18PheBu. Fluorescence spectra of TC18PheBu in aqueous solutions in the presence of pyrene as a probe further confirm the importance of hydrophobic interactions for the self-assembly. The circular dichroism (CD) spectra of TC18PheBu in supramolecular hydrogels in the presence of KF indicate that the hydrogen-bonding interaction can be disrupted by fluoride ions, which further confirm the importance of hydrogen bonding for the self-assembly of TC18PheBu.

Graphical abstractA novel chiral hydrogelator, l-phenylalanine derivative (TC18PheBu) can self-assemble in aqueous media to form supramolecular hydrogels. Investigation of the formation mechanism of the supramolecular hydrogel indicates that hydrogen bonding and hydrophobic interactions are driving forces through the characterization of POM, FT-IR, fluorescence, and CD.Figure optionsDownload full-size imageDownload as PowerPoint slide