Helical supramolecular aggregates, mesoscopic organisation and nanofibers of a perylenebisimide–chiral surfactant complex via ionic self-assembly

A chiral supramolecular liquid-crystalline material was produced by the complexation of a cationic perylene bisimide dye (PTCDI) with an anionic chiral phosphate surfactant (BDP) via ionic self-assembly. The aggregation behaviour of the PTCDI–BDP complex was investigated in detail in solution and in the bulk state. The UV-Vis and CD results show that helical supramolecular aggregates of the complex were formed with the enhancement of π–π stacking between perylene molecules in solution (due to low solubility in poor solvents) as well as in the bulk. Thin films of the complex exhibit fan-shaped textures in polarized optical microscopy (POM) investigations, which corresponds to a columnar mesophase. X-ray diffraction analyses confirmed this phase identification. Moreover, the complex formed a nanofibrillar structure, as imaged by TEM, when cast from dilute ethanol solutions.