Twisted grain boundary phases in three new chiral azobenzene series

Abstract

Three new chiral series with an azobenzene core have been synthesized and studied. The twist grain boundary smectic A and C phases, obtained with a cholesteric texture, were characterized by different techniques: binary diagram, racemic mixtures, helical pitch measurement and X-ray diffraction. Helical pitch measurements of the TGB_A and TGB_C phases were performed using Grandjean-Cano wedges and those of the S∗_C phase with homeotropic drops. The pitch values are similar to those of tolane compounds previously studied. Electro-optical properties of the S∗_C phase were measured with classical SSFLC geometry and the results are comparable with previous studies.