Antiferroelectric Chiral Smectic C Materials Having a 2-Alkyl Alkanoyl Group in the Chiral Part

Abstract

Novel antiferroelectric chiral smectic C (SmC A * ) materials are presented. Four homologous compounds having a 2-alkyl alkanoyl group in the chiral part are investigated. Three of them have SmC A * and show very short helical pitch in SmC * . In contrast, the other one has no SmC A * and exhibits rather long pitch in SmC * . This result suggests that the length of the pitch relates closely to occurrence of SmC A * . The introduction of an ethyl group into the chiral carbon instead of a methyl group increases the stability of SmC A * in contrast with decreasing that of SmA and SmC * . All four compounds show the third state even in SmC * by application of an AC field. Microscope observation indicates that the third state in SmC * is different from that in SmC A * .