Sona Sivakova

Fluorescent supramolecular liquid crystalline polymers from nucleobase-terminated monomers

While thymine or N6-(4-methoxybenzoyl)adenine terminated bis(4-alkoxy)-substituted bis(phenylethynyl)benzene monomers show no liquid crystalline behaviour by themselves, mixing the complementary nucleobase monomers together results in the formation of thermotropic liquid crystalline phases.

Liquid crystalline supramolecular polymers formed via complementary nucleobase pair interactions

We report on the effect of placement of nucleobase units, thymine or N6-(4-methoxybenzoyl)-adenine onto the ends of the mesogenic and fluorescent core: bis-4-alkoxy-substituted bis(phenylethynyl)-benzene (AA and BB type monomers). While the addition of these bulky polar groups significantly reduces the range of liquid crystalline behavior, mixing two complementary nucleobase-containing monomer units together yields stable thermotropic liquid crystalline phases. Here, we focus on the effect of non-stoichiometric mixing of AA + BB monomers. Hydrogen bonding is shown to play an important role in the formation of these LC phases consistent with the formation of oligomeric or polymeric hydrogen bonding aggregates. Differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) have been used in our studies, revealed greater stability of LC phase formation for the 1:1 mixture.