NEW FERROELECTRIC LIQUID-CRYSTALS WITH CYCLIC AND NONCYCLIC CHIRAL GROUPS

New liquid crystalline materials with cyclic proline.alkyl eater, fenc hyl, bomyl, verbenyl and 2-decalinyl and non-cyclic 1-methyl-alkyl and ethyl-lactate chiral terminal groups were studied. Ferroelectric and antiferroelectric smectic phases were found for compounds with the sem i-flexible chiral roup while derivatives with the ring chiral moieties form exclusively ferroelectric smectics. The Ps values as high as 270 nC/cm(2) in the hexatic SmI phase were detected for the l-methyl-alk yl derivatives. Generally, a lower spontaneous polarisation was detect ed for the materials with cyclic groups. This is either due to large s ize of the bulky groups causing less hindered rotation of molecules or due to admixture of conformers with opposite Ps sign.