Synthesis and characterization of new ferroelectric liquid-crystalline cyclic oligosiloxanes containing methyl-eneoxymethylene spacers

摘要

The synthesis of side-chain liquid-crystalline oligocyclosiloxanes containing methyle-neoxymethylene spacers,two different mesogenic cores (including biphenyl phenyl carboxylate or biphenyl fluorophenyl carboxylate groups) and chiral tails is presented.Differential scanning calorimetry,optical polarizing microscopy and X-ray diffraction measurements reveal liquid-crystalline properties for all of the synthesized monomers and oligomers.All cyclic oligosiloxanes exhibit enantiotropic smectic A and chiral smectic C phases.The mesogenic properties of the cyclic oligomers and side-chain liquid-crystalline precursor are discussed.