Design, synthesis and characterization of hydrogen bonded thermotropic liquid crystals

ABSTRACTA homologous series of seven linear hydrogen bonded thermotropic liquid crystals are isolated from p-n-octyloxy benzoic acid (8BAO) and p-n alkyl benzoic acids (nBA, where n varies from 2 to 8). In all the seven complexes, hydrogen bonding is a result of complementary proton-donor and electron-acceptor pairs derived from carboxylic acids of 8BAO and nBA. Spectroscopic characterization such as Fourier Transform Infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance (1HNMR, 13CNMR) are performed for all the seven complexes to confirm the intermolecular hydrogen bonding and the nature of chemical environment respectively. Seven mesogen are examined by Polarizing Optical Microscope (POM) for identification of the phase polymorphism through standard textures. Transition temperatures and corresponding enthalpy values of the individual mesogenic phases are experimentally obtained from the analysis of the respective Differential Scanning Calorimetry (DSC) thermograms. Phase diagram of this homologous...