Studies of Phase Diagram of a Liquid Crystal with 4-[2-(3-Fluorophenyl)ethyl]biphenyl Core of Molecules

Basing on the results of differential scanning calorimetry and transmitted light intensity methods and texture observations in the temperature range from - 50C to 90C phase diagram of 1-[3-fluoro-4-(1-methylheptyloxycarbonyl)phenyl]-2-[4'-(2,2,3,3,4,4,4-heptafluorobutoxybutoxy)biphenyl-4-yl]ethane was established. Monotropic system of thermodynamic phases was found. On cooling the isotropic phase transforms at 85C to ferroelectric SmC* phase and further two liquid crystalline phases, antiferroelectric $SmC*_{A}$ and SmI, and a metastable crystal Cr2 reveal. During heating exothermic anomaly in the wide temperature range was observed and ascribed to evolution of Cr2 to the stable crystal Cr1. On further heating both $SmC*_{A}$ and SmC* phases were observed. Thermodynamic parameters were calculated for all phase transitions. During rapid cooling (10 K/min) vitrification of metastable Cr2 crystal at $T_{g}$ = - 115C was registered.