Antiferroelectric chiral smectic-O*liquid crystal

A macroscopic study of chiral smectic-${\mathit{O}}^{\mathrm{*}}$ films, which float at the free surface of isotropic droplets of 1(methyl)-heptyl-terephtalidene-bis-amino cinnamate, is presented. It allows us to directly prove antiferroelectricity with in-plane polarization in the smectic-${\mathit{O}}^{\mathrm{*}}$ phase, and to confirm the herringbone structure of this original phase. The bulk antiferroelectric polarization is measured to be about 0.1 D per molecule.