Synthesis and characterization of room temperature columnar mesogens of cyclotriphosphazene with Schiff base units

Abstract

New supermolecular liquid crystals have been synthesized by attaching polycatenar aromatic units with three terminal alkyl chains through imine linking groups to a central cyclotriphosphazene ring, and these were investigated by polarizing microscopy, DSC and XRD. Compounds with several different linear terminal alkyl chains can form liquid crystals with columnar phases, and most of these are room temperature columnar phases. A model is proposed for the organization of the molecules in the columns, which is based on the nanosegregation of the aromatic cores and alkyl chains and a staggered organization of the star-shaped molecules in columns. Branching of the peripheral alkyl chains leads to an amorphous material.