Lamellar to lamellar phase transition driven by conformation change of a dumbbell-shaped liquid crystal oligomer

Abstract

We prepared novel dumbbell-shaped liquid crystal oligomers in which two mesogens are connected via a flexible spacer, and investigated their physical properties using optical microscopy, differential scanning calorimetry and X-ray diffraction. Compound _I_ possessing an alkyl chain as the central group exhibited a nematic phase. On the other hand, compound _II_ possessing a perfluoroalkyl chain as the central group instead of the alkyl chain exhibited nematic, bilayer smectic A and intercalated smectic A' phases. We discuss their phase transition behavior in terms of the molecular shape.