Hydrogen-bonded polyphilic block mesogens with semiperfluorinated segments

Two 2,4-diamino-6-phenyl-1,3,5-triazines carrying either one or two alkoxy chains at the phenyl substituent have been investigated in binary mixtures with two-chain partially fluorinated benzoic acids. Equimolar compositions of the complementary molecular species form discrete hydrogen-bonded dimeric supermolecules. The dimers organize to infinite ribbons of parallel aligned H-bonded polar aromatic cores that are separated by mixed aliphatic/fluorinated regions. The cross-sectional shape of the ribbon aggregates and, therefore, the two-dimensional lattice symmetries of the ribbon phases, rectangular or oblique, are defined by the number of alkoxy chains of the triazine component. Docking of 2 or 3 equiv of the semiperfluorinated benzoic acids to the diaminotriazine core leads to H-bonded aggregates with a circular cross-sectional shape and, consequently, to the formation of columnar phases on a two-dimensional hexagonal lattice.