The first bent-core liquid crystal materials with a photo-active azo linkage exhibiting the B7 mesophase are reported. The lower homologues of the bent-core compounds display the B1 phase and higher homologues show the B7 mesophase. The mesomorphic properties were characterized using polarized optical microscopy, differential scanning calorimetry and X-ray diffraction. The B7 phase of these materials establishes ferroelectric switching characteristics with anticlinic organization (SmCAPF) of the molecules in the layers. The bent-core molecules with an azo linkage are important for photoisomerization studies, which indicate trans to cis isomerization at 30 s, whereas the reverse processes take place over 40 s in chloroform.
本研究首次报道了具有光活性偶氮连接的弯曲核液晶材料,这些材料显示出 B7 介相。弯核化合物的低同系物显示 B1 相,高同系物显示 B7 介相。使用偏振光学显微镜、差示扫描量热法和 X 射线衍射法对介观性质进行了表征。这些材料的 B7 相具有
铁电开关特性,层中的分子具有反折组织(SmCAPF)。具有偶氮连接的弯曲核分子对光异构化研究非常重要,研究表明,反式到顺式异构化过程在 30 秒内完成,而在
氯仿中的反向过程则需要 40 秒。