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-hexa diyne, its polymerization and the purification of the polymer, which is sol uble in common organic solvents, are reported. Results from powder X-ray di ffraction 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 (Col(hd)) to a less ordered (Col(hd)) structure around 85 degrees C. The role played by t he long alkyl chains in the formation of the supramolecular hexagonal mesop hase is emphasized by comparing these results with those obtained from an a nalogous polymer with dodecyl substituents which exhibits only the Col(hd) structure over the whole range of temperature explored.