TILT-POLARIZATION COUPLING IN A HOMOLOGOUS SERIES OF FERROELECTRIC LIQUID-CRYSTALS

The synthesis of the homologous series methylpentanoyloxyl-4'-[4-alkyl benzoyloxy]biphenyl and their chiral and mesomorphic properties are re ported. The enantiomeric excess is deduced from H-1 NMR spectroscopy. For the hexyl derivative, a twist grain boundary state (TGB(A)) media tes the cholesteric to SmC phase transition and its stability is disc ussed in terms of chirality and surface interactions. In the SmC phas e, measurements of the spontaneous polarization are reported and the t emperature dependence of the tilt angle is determined from the electro -optical switching process or deduced from X-ray measurements of the s mectic layer thickness, respectively. The tilt-polarization coupling i s discussed within the framework of the 'generalized Landau model' pro posed by Zeks and Blinc.