Bilayer-by-bilayer antiferroelectric ordering in freely suspended films ofan achiral polymer-monomer liquid crystal mixture

Thin freely suspended films of a mixture of an achiral side-chain liquid cr ystal polymer and its monomer have been studied with depolarized reflected light microscopy. We observe that regions with an odd number of bilayers ex hibit a net spontaneous polarization in the tilt plane of the molecules, wh ile regions with an even number of bilayers have no net polarization. These odd-even effects are direct evidence that the tilted smectic bilayers are anticlinic at the polymer backbone and synclinic at bilayer interface and c onfirm that the phase is bilayer-by-bilayer antiferroelectric.