Phase Behaviour of Tbba Under High Pressure by Differential Thermal Analysis (DTA)

Abstract
The phase behaviour of TBBA has been studied by high-pressure differential thermal analysis (DTA) up to 3 kbar in the temperature range from 300 to 600K. The T-p phase diagram of TBBA is very complex. At normal pressure a new metastable solid phase has been found. At higher pressures the smectic VI and the smectic VII phases vanish and another new phase is pressure induced. The enthalpy of the smectic A/nematic transition decreases drastically with increasing pressure suggesting a tricritical point at about 1000 bar and 515 K.