Phase trandition mechanism of reentrant liquid crystal, CBOBP

Abstract

CBOBP (4-cyanobenzoyloxy-[4-octylbenzoyloxy]-p-phenylene), exhibits a transition sequence, I-N-S_<Ad>-N-S<Al>-crystal (doubly reentrance sequence) on lowering the temperature. The second N phase is called reentrant nematic (RN). Due to this peculiarity, the nature of this transition sequence has been one of the interesting topics in recent liquid crystal research. We made neutron diffraction study to clarify the structure of the liquid crystalline phases and hence to clarify the microscopic mechanism of this phenomenon. For this purpose a compound with perdeuterated chain, CBOBP-d17 was prepared. SANS-U instrument was used at an wavelength of 7Å with a velocity selector.