Supramolecular organization in the solid state of a novel soluble polydiacetylene

The synthesis of the monomer 1,6-bis(3,6-dihexadecyl-N-carbazolyl)-2,4-hexadiyne, its polymerization and the purification of the polymer, which is soluble in common organic solvents, are reported. Results from powder X-ray diffraction studies carried out on the red form of the polymer are discussed. The red polymer chains self-assemble into cylindrical shapes which produce hexagonal columnar mesophases with a transition from a more (Colho) to a less ordered (Colhd) structure around 85 C. The role played by the long alkyl chains in the formation of the supramolecular hexagonal mesophase is emphasized by comparing these results with those obtained from an analogous polymer with dodecyl substituents which exhibits only the Colhd structure over the whole range of temperature explored.