Azomethine sulfone macromers with thermotropic liquid crystalline behavior

New azomethine sulfone macromers containing benzylideneaniline mesogens were prepared by the conventional methods available in the literature by condensing the sulfone aldehyde monomer with aromatic diamines (DA1–DA5) using N,N-dimethylformamide as solvent. The macromers (M1–M5) were confirmed by IR, 1H-NMR, and elemental analyses, and were characterized by thermogravimetric analysis and X-ray diffraction. Their thermotropic liquid crystalline behavior was studied using polarization light microscopy, thermo-optical analysis, and differential scanning calorimetry. A nematic texture was observed for macromers M1–M3 containing the two benzylideneaniline mesogens either connected by etheric (M1), methylenic links (M2), or directly coupled (M3). Conformational energy and mesogenic index (MI) calculations were performed and used to explain the TLC behavior of the macromers studied.