SHEET-SHAPED MESOGENS BASED ON 1,3,5-TRIAZINES - VARIATION OF COLUMNAR MESOPHASES THROUGH INTERMOLECULAR HYDROGEN-BONDING

The mesomorphic behaviour of a liquid crystalline sheet-shaped 2,4,6-t riarylamino-1,3,5-triazine bearing six peripheral decyloxy chains has been investigated in binary mixtures with two-fold alkoxy substituted non-mesomorphic benzoic acids. Each investigated equimolar mixture exh ibits an enantiotropic columnar phase with either a hexagonal or a rec tangular lattice. The two-dimensional lattice parameters depend on the length and positions of the flexible alkoxy chains of the aromatic ca rboxylic acids. The structure formation of the mixed systems giving ri se to variations of the mesophase structure of the pure triarylaminotr iazine results from intermolecular hydrogen bonding between the comple mentary melamine and acid components.