Hydrogen-bonded block mesogens with fluorinated molecular fragments

An alkoxyphenyl substituted melamine derivative has been investigated in binary mixtures with a two-chain semiperfluorinated benzoic acid. The two components are non-liquid crystalline in their own right. Equimolar mixtures of the melamine with the complementary benzoic acid form discrete hydrogen-bonded heterodimers. The dimeric supermolecules exhibit an induced rectangular columnar mesophase with two-dimensional c2mm lattice symmetry. The columnar phase represents a ribbon phase resulting from the collapse of smectic bilayers. Docking of two or three equivalents of the two-chain benzoic acid to the melamine core leads to the induction of hexagonal columnar mesophases.