Non-linear boomerang-shaped liquid crystals derived from 2,5-bis(p-hydroxyphenyl)-1,3,4-oxadiazole

Boomerang-shaped liquid crystals based on 2,5-bis(p-hydroxyphenyl)-1,3,4-oxadiazole (ODBP) having a ~ 134° bend in the mesogenic cores were synthesized and their properties investigated by optical microscopy and differential scanning calorimetry. Substituting the nonlinear ODBP mesogenic core with p-dodecyloxyphenyl tails resulted in a non-linear mesogen that exhibited five distinct mesophases and a clearing temperature of 204°C. The highest temperature phase appears to be nematic followed by a smectic C phase. The latter phase in freely suspended films does not appear to exhibit polar order. The highest temperature phase of 4,4'(1,3,4-Oxadiazole-2,5-diyl) di-p-heptylbenzoate shows a schlieren texture with a 2-brush pattern exclusively.