First Order Paraelectric-Antiferroelectric Phase Transition in a Chiral Smectic Liquid Crystal of a Fluorine Containing Phenyl Pyrimidine Derivative

Abstract

The first-order phase transition between paraelectric SmA and antiferroelectric SmC A * phases has been observed for the first time in ( S )-4-(1-trifluoromethylheptyloxycarbonyl)phenyl 4-(5-dodecyloxypyrimidin-2-yl)benzoate (TFMHPDOPB). Three pieces of evidence for the first-order phase transition are shown by means of DSC, X-ray and dielectric measurements. The DSC peak of the SmA-SmC A * transition is as large as the one for the Iso-SmA transition. The temperature dependences of the interlayer spacing determined by X-ray diffraction and of the dielectric constant reveal marked discontinuous jumps at the SmA-SmC A * phase transition.