Polymorphism of righthanded octyloxycyanobiphenyl

Polymorphism of the octyloxycyanobiphenyl isomer 4-(1(S)-methylheptyloxy)-4'cyanobiphenyl (8OCB) was studied by means of adiabatic calorimetry, infrared spectroscopy and polarizing microscopy. Two crystalline phases, C1 and C2, were identified and their thermodynamic parameters measured. A monotropic system of the metastable C1 and stable C2 crystals was obtained. Far infrared absorption and polarizing microscopy textures are discussed.