Mesophase behaviour of 2,5-dibenzoyloxy-p-benzoquinone derivatives and tetrahydrobenzene tetraesters

Laterally Substituted and Swallow‐Tailed Liquid Crystals

“…[44,46]), but corresponding four-ring mesogens, e.g. the oximesters 13b with two laterally attached nonyl groups, can exhibit nematic phases with clearing points at about 140 "C [27].…”

Chemical Structure and Mesogenic Properties

“…With somewhat different substituents in the given example, the compound exhibits two smectic A phases, one of which has an undulating structure [199]. Berg et al [200] have reported on the liquid crystalline properties of four-fold substituted benzene derivatives, the structure of which may be considered as a basic molecule with two ring-containing lateral substituents (11 [200]). According to X-ray studies in the solid state, compounds of this type are cross shaped, with the ring planes 11 Cr 123 (N 121) I of the laterally attached substituents lying perpendicular to those of the basic moiety.…”

Influence of molecular weight and polydispersity on phase behaviour of polyesters with laterally fixed or cross-shaped mesogens

“…At a molecular weight of 16 000 (M,) the clearing region is about 130"C, at 14 000 (M,) about 110°C and the fraction of about 12000 (M,) is partially isotropic already above the glass transition. Below a molecular weight of about 10000 (M,) there exists no mesomorphic behaviour, in contrast to some monodisperse low molecular weight model compounds [9]. Why the liquid-crystalline phase changes so dramatically above a relatively high molecular weight is not yet understood.…”