ACHIRAL SWALLOW-TAILED MATERIALS WITH ANTIFERROELECTRIC-LIKE STRUCTURE AND THEIR POTENTIAL USE IN ANTIFERROELECTRIC MIXTURES

Achiral 'swallow-tailed' liquid crystalline materials are known to giv e alternating-tilt smectic C phases (S-Calt) which have structural sim ilarities to the chiral antiferroelectric phases denoted as S(CA). Th is paper describes the synthesis and characterization of three achiral branched-alkyl decyloxybiphenyl-4-carbonyloxy)-3-fluorobenzoates. Opt ical microscopy and differential scanning calorimetry confirm that the se materials show S-Calt and overlying S-A phases. The compounds were investigated as potential hosts which could be doped with a chiral fer roelectric liquid crystal so as to provide a viable antiferroelectric mixture. These studies (microscopy and differential scanning calorimet ry), to characterize the properties of the mixtures, show that antifer roelectric phases are induced. However, switching studies show that th e antiferroelectric phases are extremely stable, a property which is a lmost certainly a consequence of the length of the lateral branching g roups (ethyl, propyl and butyl).