Liquid crystalline dimers containing a cholesteryl group: chiral smectic phases and TGBA* phase

A new series of liquid crystalline dimers containing a cholesteryl group were synthesised, exhibiting multiple mesophases including chiral smectic phases (SmC* and SmA*), twist grain boundary phases (TGBA*), and chiral nematic phase (N*). The chemical structure and liquid crystal properties of the dimers were characterised by FTIR, 1H-NMR, DSC, POM and XRD. It was in evidence that the lengths of the terminal tail and the flexible spacer were the decisive factors of the mesophase behaviours.