Organogels and Liquid Crystalline Properties of Amino Acid-Based Dendrons: A Systematic Study on Structure–Property Relationship

Abstract

Self-assembly behaviors of a series of amino acids-based dendrons, from the first generation (G1) to the third generation (G3) with various focal moieties or peripheral groups, were systematically studied. The supramolecular structures in organogels, thermotropic and lyotropic liquid crystals (LCs) were measured. The influence of the focal groups, dendritic branches, and generation numbers on the mesophase of organogels or LCs was studied by a combination of experimental techniques including transmission electronic spectrometry (TEM), atomic force microscopy (AFM), infrared (IR) spectra, wide-angle X-ray diffraction (WAXD), and small-angle X-ray scattering (SAXS). It was found that the gelation ability of the dendrons in organic solvents was highly related to the generation; namely, none of the G1 dendrons could form organogels, G2 dendrons displayed good gelation ability, and G3 dendrons gelled the organic solvents with the lowest critical gelation concentration. Oscillatory shear measurements indicated that the gels behaved as viscoelastic materials with good tolerance to external shear force. In addition, all of G3 dendrons and some G2 dendrons were capable of self-organizing to afford the thermotropic and lyotropic LCs.