Structure and thermal behavior of hydrogen-bonded liquid-crystalline polymers

Acrylic LC monomers based on derivatives of alkoxybenzoic acids with a variable aliphatic spacer length and their related polymers were synthesized and studied by IR spectroscopy, DSC, and X-ray diffraction. For all the research subjects, the formation of hydrogen-bonded dimers between alkoxybenzoic acid fragments was shown to bring about the development of LC structures. It was demonstrated that the length of an aliphatic spacer and the odd-even effect influence the structure of a mesophase and the temperatures of phase transitions. It was disclosed that, upon transition from the studied low-molecular-mass compounds to the corresponding polymeric systems, a tendency toward development of smectic packing appears and the smectic C-phase becomes predominant.