Shoji Yoshiaki, Kobayashi Miki, Kosaka Atsuko, Haruki Rie, Kumai Reiji, Adachi Shin-Ichi, Kajitani Takashi, Fukushima Takanori
Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology 4259 Nagatsuta, Midori-ku Yokohama 226-8503 Japan
Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology 4259 Nagatsuta, Midori-ku Yokohama 226-8503 Japan.
Chem Sci. 2022 Jul 19;13(34):9891-9901. doi: 10.1039/d2sc03677k. eCollection 2022 Aug 31.
The alignment control of discotic columnar liquid crystals (LCs), featuring a low motility of the constituent molecules and thus having a large viscosity, is a challenging task. Here we show that triphenylene hexacarboxylic ester, when functionalized with hybrid side chains consisting of alkyl and perfluoroalkyl groups in an appropriate ratio, gives a hexagonal columnar (Col) LC capable of selectively forming large-area uniform homeotropic or homogeneous alignments, upon cooling from its isotropic melt or upon application of a shear force at its LC temperature, respectively. In addition to the alignment switching ability, each alignment state remains persistent unless the LC is heated to its melting temperature. X-ray diffraction analysis under the application of a shear force, together with polarized optical microscopy observations, revealed how the columnar assembly is changed during the alignment-switching process. The remarkable behavior of the discotic LC is discussed in terms of its rheological properties.
盘状柱状液晶（LCs）的取向控制是一项具有挑战性的任务，因为其组成分子的运动性较低，因此具有较大的粘度。在这里，我们表明，当苯并菲六羧酸酯用适当比例的烷基和全氟烷基组成的混合侧链进行功能化时，从其各向同性熔体冷却或在其液晶温度下施加剪切力时，会分别形成能够选择性地形成大面积均匀垂直取向或均匀取向的六方柱状（Col）液晶。除了取向切换能力外，除非将液晶加热到其熔点温度，否则每种取向状态都会保持稳定。在施加剪切力的情况下进行的X射线衍射分析以及偏光显微镜观察揭示了在取向切换过程中柱状组装体是如何变化的。从其流变学性质的角度讨论了盘状液晶的显著行为。
