Fundamental Study On Allyl And Siloxane Tailed Discotic Liquid Crystals

The discotic liquid crystalline materials with different linking groups (-COO, -N=N, -CH=N, -N=CH and biphenyl) have\ud been synthesized. The assignment of molecular structure of intermediates and the target compounds have been\ud substantiated by spectroscopic techniques (FT-IR and FT-NMR). New mesomorphic phase and sequence have been\ud I confirmed wherein the biphenyl branched discotic molecules shows discotic columnar mesophase. It possesses crystal to hexagonal columnar (Colh) phase at 86°C and Colh phase to isotropic at 184°C. The enthalpy change associated\ud with the mesophase-to-isotropic phase transition is quite low indicating that the degree of order within the mesophases is low. The remaining linking group have also led to various meso phases with high temperature range. These mesophase possesses high viscous fluidity and hence identification of mesophase requires the use of X-ray difraction. Other series of triazole branched discotic liquid crystalline compounds have also been synthesized (CnH2n+1; n=6 -16) and the mesophase of the compounds are homeotropically aligned. Further investication such as DSC and X-ray analysis are recommended and will be pursued in future. Besides, the discotic shape has also been constructed from the phloroglucinol-based star-shaped materials which have displayed anomalous feature particularly on the phase behavour. The mesomorphic properties of hydrogen bonded complexes and organogel of self-assembled 1,2-bis[4-(4 - (10 decyloxy) phenylazo)]benzoylhydrazine dimer have also been isolated and reported in the journals