Siloxane-Containing Thermotropic Liquid Crystals Based on New Azomethine Dimesogens

Abstract

Two dimesogenic compounds with azomethine links and phenolic functionality were synthesized and used to prepare telechelic oligomers with various siloxane contents, by condensation reactions involving or, w-bis(chloromethyl)polysiloxanes of different molecular weights. The structures of the compounds obtained were confirmed by IR and 'H-NMR spectroscopy, and they were characterized by differential scanning calorimetry (DSC). The synthesized dimesogenic compounds and dimeric oligomers exhibited thermotropic liquid crystalline behaviour, evidenced by polarized light microscopy (PLM). The introduction of the siloxane moieties led to an important decrease of the melting temperature as compared with the starting phenols, accompanied by a serious broadening of the mesophase domain.