A structural investigation of the liquid crystal phases of 8SI.

The smectic phases of the compound 4-(2'-methylbutyl)phenyl 4'-n-octylbiphenyl- 4-carboxylate 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 8SI 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.