A structural investigation of the liquid crystal phases of 4-(2'-methylbutyl)phenyl 4'-n-octylbiphenyl-4-carboxylate

Abstract

The smectic phases of the compound 4-(2'-methylbutyl)phenyl 4'-n-octylbiphenyl-4-carboxylate (2M4P8BC) were studied by means of polarized optical microscopy, miscibility, DSC, and X-ray diffraction techniques. The phase sequence Cr ↔ G ↔ J ↔ I ↔ C ↔ A has been determined, and consequently 2M4P8BC has been shown to be the first example of a pure material exhibiting a J to G phase transition. In the optically pure form, the I* phase is a chiral hexatic phase, whereas the J* and G* phases were found to be nonchiral crystal phases. The C-centred monoclinic lattice parameters have been determined