Novel Ferroelectric and Antiferroelectric Smectic and Columnar Mesophases in Fluorinated Symmetrical Bent-Core Compounds
Novel Ferroelectric and Antiferroelectric Smectic and Columnar Mesophases in Fluorinated Symmetrical Bent-Core Compounds
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DOI：
10.1021/cm048684n
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发表时间：
2005
影响因子：
8.6
通讯作者：
R. A. Reddy;V. Raghunathan;B. K. Sadashiva
中科院分区：
文献类型：
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作者：
R. A. Reddy;V. Raghunathan;B. K. Sadashiva
我们报告了新型弯核（BC）介晶的合成和介晶性质，该介晶表现出具有矩形和倾斜晶格的新型反铁电开关柱状相。具有短链的同系物显示出典型的不可转换矩形柱状（B1）相，并且中间同系物获得了铁电转换近晶相。有趣的是，随着链长度的增加，诱导出可转换的柱状相，并且定向良好的样品的 X 射线衍射图表明存在矩形和倾斜晶格。根据实验观察，已经为这些阶段提出了可能的模型。在高温和低温下，在铁电和反铁电矩形柱状相中也分别观察到了场感应的 SmCSPF 和 Mx 相。对于铁电相，还首次观察到相反旋性的手性域的切换以及域内手性意义的变化。
We report the synthesis and mesomorphic properties of new bent-core (BC) mesogens exhibiting novel antiferroelectric switching columnar phases with rectangular as well as oblique lattices. The homologues with short chains show typical nonswitchable rectangular columnar (B1) phase and a ferroelectric switching smectic phase is obtained for the middle homologues. Interestingly, with increasing chain length, the switchable columnar phases are induced and the X-ray diffraction pattern with well-oriented samples indicates the presence of rectangular and oblique lattices. On the basis of the experimental observations, possible models have been proposed for these phases. Field-induced SmCSPF and Mx phases are also observed in the ferroelectric and antiferroelectric rectangular columnar phases, at high and low temperatures, respectively. Switching chiral domains of opposite handedness as well as a change in the sense of chirality within a domain could also be observed for the first time for the ferroelectric phas...