Achiral liquid crystals with an anticlinic smectic C structure

The mesomorphic properties of two series of new achiral symmetrically-subst ituted ("swallow-tailed") liquid crystals are presented. The branched-alkyl 4-(4'-alkyloxybiphenyl-4-carbonyloxy)-3-fluorobenzoates form the anticlini c smectic C (SmCalt) phase which is found to be miscible with the SmCA* pha se of standard antiferroelectric materials. The effect of variations in the lengths of both the branched and unbranched chains on the occurrence of th e SmCalt phase was investigated and the significance of the size of the swa llowtail moiety on the formation of the SmCalt phase is discussed.