New Liquid-Crystalline Materials Through Ionic Self-Assembly: Phase Characterization and Alignment Properties

The thermotropic and lyotropic LC phases of the ionic self-assembled complex N’N-bis(2-(trimethylammonium)ethylene) – perylene- 3,4,9,10 – tetracarboxyldiimide – bis(2-ethylhexyl) sulfosuccinate (1-AOT) were studied by polarized light microscopy, DSC and X-ray scattering techniques. A 2D columnar thermotropic LC phase with p-p stacking of the perylene tectonic units and a lyotropic LC phase in dimethyl sulfoxide (DMSO) were found. A variety of techniques were applied to align both systems, including surface interactions, electric and magnetic fields, shear force and controlled domain formation at the LC – isotropic phase transition front (PTF). Characterization of the alignment in films was performed by polarized UV-Visible spectroscopy and transmission null-ellipsometry. The best results were obtained for alignment of the material in a lyotropic phase by controlled domain formation at the phase transition front (PTF) of the LC – isotropic phase transition. In this case a dichroic ratio of 18 was achieved with packing of columns of perylenediimide tectons perpendicular to the PTF. 2