Bent-shaped mesogens without an azomethine joint

Abstract

A new series of banana-shaped mesogens with ethylene links in the branches and laterally substituted are presented. They form B₁, B₂, B₆ and B₇-like phases. The B₇-like and B₂ phases are not miscible although identical crystallographic structures are deduced from X-ray studies. The switching in the B₇-like phase is without a threshold and occurs only in a small number of domains. Dielectric measurements do not confirm ferroelectric properties for the B7-like phase, and only a weak non-collective relaxation process was observed. In the B₂ phase a collective and weak dielectric mode was detected. The B₁ phase exhibits a columnar structure with a large rectangular cell 111.6 × 51 Ų.