Liquid Crystalline Derivatives Containing Fluorene and Fluorenone Structures

Abstract

The authors have synthesized liquid crystalline materials containing fluorene, fluorenone and biphenyl structures. Among these materials, comparison have been made for 1) Thermal stabilities for smectic A and smectic C* phases. 2) Tilt angles and spontaneous polarizations in the surface stabilized ferroelectric liquid crystal. These properties are markedly dependent on the structures of the central cores. In the fluorene derivatives, the tilt angles and the spontaneous polarizations were both smaller than those in the biphenyl derivatives. On the other hand, in the fluorenone derivatives, both larger tilt angles and greater spontaneous polarizations than for fluorene derivatives were observed. This increase is considered to be due to the induction force, which is introduced by the dipole moment perpendicular to the molecules of the fluorenone structure. Concerning the stability of smectic A phase and smectic C* phase for these derivatives, the authors confirmed the same result as the conclusion of the authors' previous work¹.