Dye-Assisted Structural Modulation of Hydrogen-Bonded Binary Supramolecular Polymers

Binary hydrogen-bonded supramolecular polymers composed of a dimeric melamine (bis(melamine)) and barbiturate-type merocyanine dyes are prepared in aliphatic solvents. Macroscopic structure and rheological behavior of the supramolecular polymers are investigated by scanning electron microscopic observation and dynamic rheological measurement. Despite conformational flexibility in the bis(melamine) component, supramolecular polymers exhibit well-defined one-dimensional fibrous or two-dimensional sheetlike macroscopic structures, which are dependent on the blended merocyanine dyes. UV−vis studies of the supramolecular polymerization in dilute solutions imply that the merocyanine dyes exist as self-aggregated state upon supramolecular polymerization with the bis(melamine) component. This observation strongly suggests the presence of secondary structures of the quasi-one-dimensional flexible supramolecular polymers.