Helical columnar liquid crystals based on dendritic peptides substituted perylene bisimides

Abstract

New columnar liquid crystals based on perylene bisimides (PBIs) were synthesized by introducing dendritic peptides onto the two ends of the imide. The self-assembly behaviour of PBIs in solution and in film was investigated through temperature-dependent and solvent-dependent ultraviolet-visible absorption spectroscopy. The mesomorphic behaviour was studied by polarizing optical microscopy, differential scanning calorimetry, small-angle X-ray diffraction and temperature-dependent Fourier transform infrared spectroscopy. Ordered columnar mesophases were observed for PBIs at room temperature. Circular dichroism studies demonstrate that these materials exhibit supramolecular optical activity in the liquid crystalline state, which is attributed to helical columnar organization. The hydrogen bonds at the periphery of PBIs result in the ordered columnar mesophases structure with small inter-disk distances of 3.4 Å