The synthesis and characterization of twenty seven new compounds belonging to three homologous series of compounds derived from 3-hydroxybenzoic acid are reported. One of the terminal positions of the constituent molecules of these compounds is substituted with a strongly polar cyano group while the other end contains an n-alkyl chain attached to a biphenyl moiety. Twenty two of these compounds show the polar partial bilayer biaxial smectic A phase which is antiferroelectric in nature. In addition, a direct transition from the nematic phase to the polar partial bilayer biaxial smectic A phase which has not been seen before is also reported. The mesophases have been characterized using polarized light optical microscopy, differential scanning calorimetry, X-ray diffraction studies and electro-optical experiments.
报告中介绍了属于 3-hydroxybenzoic acid 衍生的三个同源化合物系列的 27 种新化合物的合成和特性。这些化合物组成分子的一个末端位置被一个强极性
氰基取代,而另一端则含有一个连接到
联苯分子上的正烷基链。这些化合物中有 22 种显示出极性部分双层双轴平滑 A 相,其性质为反
铁电性。此外,还报道了从向列相直接过渡到极性部分双双轴 Smectic A 相的情况,这是以前从未见过的。利用偏振光光学显微镜、差示扫描量热法、X 射线衍射研究和电光实验对这些介相进行了表征。