Siloxane -terminated phenylpyrimidine liquid crystal hosts

We report the synthesis and characterization of trisiloxane-terminated liquid crystals with 2-phenylpyrimidine cores that form partially bilayered SmA and SmC phases. Variable temperature measurements of smectic layer spacings by powder X-ray diffraction combined with measurements of optical tilt angles and observations of birefringence changes by polarized optical microscopy reveal that the trisiloxane end-group causes the SmA–SmC transition …