Volumetric, dielectric, calorimetric and X-ray studies of smectogenic 10PBO8 at atmospheric and elevated pressures

X-ray diffraction data of 2-(4-octylcarbonyloxyphenyl)-5-decylpyrimidine (10PBO8) are presented. The substance exhibits two crystalline and smectic C (SmC) phases on heating and a SmC–monotropic crystalline smectic B (SmBcr) SmBcr–crystal sequence of phase transitions on cooling. Above ca. 15 MPa, the SmBcr phase becomes enantiotropic (reversible polymorphism). The phase behaviour and molecular dynamics in the liquid crystalline phases are analysed and discussed, with the conformational component of the total entropy for the SmC–isotropic liquid transition estimated. We also calculate from the PVT results the potential parameter characterising the steepness of the interaction potential