Wu Jianyun, Takeda Takashi, Hoshino Norihisa, Akutagawa Tomoyuki
Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan.
Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
J Phys Chem B. 2020 Aug 13;124(32):7067-7074. doi: 10.1021/acs.jpcb.0c03365. Epub 2020 Jul 29.
The discotic hexagonal columnar (Col) liquid crystalline phases of simple benzene derivatives bearing -CONHCH chains at the 1-, 3-, and 5-positions () and 1-, 2-, 4-, and 5-positions () display ferroelectricity and antiferroelectricity, respectively. The phase transition behavior, molecular assembly structures, dielectric response, and ferroelectric properties of their mixed crystals [()()] were evaluated to clarify the nanoscaling effect on the collective inversion of the one-dimensional (1D) N-H···O═ hydrogen bonding interaction observed in the () chain. A small quantity of doped into ( ≤ 0.03) maintained the ferroelectric polarization-electric field response (-) in the ()() chains, where the antiferroelectric molecules in the ferroelectric column act as a pinning potential site for dipole inversion. On the contrary, a relatively large amount of doping ( ≥ 0.1) forms a domain separation state between the hydrogen-bonded () and () columns, in which the ferroelectric - hysteresis completely disappeared. The correlation length for the appearance of ferroelectricity in the 1D column was estimated to be ∼40 nm in the Col liquid crystalline phase of .
在1、3和5位（ ）以及1、2、4和5位（ ）带有-CONHCH链的简单苯衍生物的盘状六方柱状（Col）液晶相分别表现出铁电性和反铁电性。对它们的混合晶体[（ ）（ ）]的相变行为、分子组装结构、介电响应和铁电性能进行了评估，以阐明对在（ ）链中观察到的一维（1D）N-H···O═氢键相互作用的集体反转的纳米尺度效应。少量的 掺杂到 中（ ≤0.03），在（ ）（ ）链中保持了铁电极化-电场响应（-），其中铁电 柱中的反铁电 分子充当偶极反转的钉扎势位点。相反，相对大量的 掺杂（ ≥0.1）在氢键连接的（ ）和（ ）柱之间形成了畴分离状态，其中铁电 - 滞后完全消失。在 的Col液晶相中，一维柱中出现铁电性的相关长度估计约为40nm。
