A novel series of ferroelectric liquid crystals with a¯uorinated asymmetric frame were synthesized by utilizing optically active (S)-2-, (S)-3-, (S)-4-and (S)-5-¯uoroalkanols prepared from corresponding (R)-1,2-epoxyalkanes. Their mesomorphic and physical properties, such as spontaneous polarization, optic tilt angle and response time, were investigated systematically in a series of homologous compounds having the chiral centre at di erent positions on tails of various lengths. All the compounds exhibited the chiral smectic C phase in a wide range of temperatures and were found to possess a fast response time in spite of the small magnitude of the spontaneous polarization.

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Hexamethylenebis(tert-butylcarbodiimide) was subjected to polyaddition reaction with 1,4-bui.anediol, 1,lO-decanediol, 1,4-cyclohexanedimethanol, p-xylylene glycol and 4,4'dimercaptobiphenyl to obtain linear polypseudourea ether or polypseudothiourea ether. ZUSAMMENFASSUNG:Mit Hexamethylen-bis-tert-butylcarbodiimid und 1,4-Butandiol, 1,lO-Decandiol, 1,4-Dimethylolcyclohexan, p-Xylylenglykol bzw. 4,4'-Dimercaptobiphenyl wurden Polyadditionsreaktionen durchgefiihrt. Es wurden lineare Polypseudoharnstoff-ather oder Polypseudothioharnstoff-iither erhalten.