Synthesis and characterization of hydrogen bonded liquid crystalline block copolymers based on a Schiff base moiety

Abstract

Two new series of supramolecular liquid crystalline block copolymers have been synthesized. The first, is based on a backbone that contains carboxylic acid groups. The second is a side chain block copolymer exhibiting hydrogen bonding between the carboxylic acid and the pyridine moiety of a simple low molar mass molecule. These copolymers contain two different flexible spacer lengths, the first fixed at two methylene groups, while the other spacer varies from two to seven groups. The phase behavior and transitional properties of these series have been analyzed by optical polarized microscopy and differential scanning calorimetry, while the structures and properties of the prepared compounds were determined by spectroscopic techniques, elemental analysis, thermogravimetric analysis, and powdered Xray diffraction.

Recent synthetic advances in pyridine-based thermotropic mesogens

“…Further, compound 114 and potassium carbonate were dissolved in methanol and stirred for 4 h. Aer the completion of the reaction, DCM extraction was performed, followed by washing with water and brine. Further, the organic layer was dried, followed by evaporation of the solvent under reduced pressure to yield 4-(4-ethynylphenyl) pyridine (115). In a two-way ask, compound 115 and Et 3 N were dissolved in THF, and the solution was bubbled with nitrogen.…”