Mechanism of supercoolling below the solid-smectic phase transition point of CBOBP

Abstract

CBOBP (4-cyanobenzoyloxy-[4-octylbenzoyloxy]-p-phenylene), exhibits a transition sequence, I-N-S_<Ad>-RN-S_<A1>-crystal (doubly reentrance sequence) on lowering the temperature. On the other hand, CBOBP exhibits the supercooling state below the solid-S_<A1> phase transition point. We made neutron diffraction study and molecular energy calculation to clarify the structure of the liquid crystalline phases and hence to clarify the microscopic mechanism of this phenomenon. For neutron diffraction study a compound with perdeuterated chain, CBOBP-d17 was prepared. SANS-U instrument was used at an wavelength of 7Å with a velocity selector. Molecular electoron potential map of CBOBP are calculated by ab-initio method.