Broad temperature range of cubic blue phase present in simple binary mixture systems containing rodlike Schiff base mesogens with tolane moiety
作者:Chiung-Cheng Huang、Yu-Hao Chen、Sheng-Yen Chen、Yi-Zeng Sun、Zong-Ye Wu、Mei-Ching Yu、Bo-Hao Chen、I-Jui Hsu、Lai-Chin Wu、Jey-Jau Lee
DOI:10.1039/c5sm02920a
日期:——
Four simple rodlike Schiff base mesogens with tolane moiety were synthesized and applied to stabilize cubic blue phases (BPs) in simple binary mixture systems for the first time. When the chiral additive ISO(6OBA)2 or R811 was added into a chiral salicylaldimine-based compound, the temperature range of the cubic BP could be extended by more than 20 °C. However, when the chiral Schiff base mesogen was blended with chiral dopant possessing opposite handedness, S811, BPs could not be observed. Interestingly, the widest temperature range of the cubic BPs (∼35 °C) could be induced by adding the rodlike chiral dopant R811 or S811 into the rodlike racemic Schiff base mesogen with hydroxyl group. On the basis of our experimental results and molecular modeling, the appearance and temperature range of the BPs are affected by the dipole moment and the biaxiality of the molecular geometry. Accordingly, we demonstrated that the hydroxyl group and the methyl branch in this type of Schiff base mesogen play an important role in the stabilization of BPs.
研究人员合成了四种具有甲苯基的简单棒状希夫碱中间体,并首次将其用于稳定简单二元混合物体系中的立方蓝相(BP)。在手性水杨醛基化合物中加入手性添加剂 ISO(6OBA)2 或 R811 时,立方蓝相的温度范围可延长 20 ℃ 以上。然而,当手性席夫碱中间体与具有相反手性的手性掺杂剂 S811 混合时,则无法观察到 BP。有趣的是,在带有羟基的棒状外消旋席夫碱中间体中加入棒状手性掺杂剂 R811 或 S811,可以诱导出最宽的立方 BPs 温度范围(∼35 °C)。根据我们的实验结果和分子建模,BPs 的出现和温度范围受到分子几何形状的偶极矩和双轴性的影响。因此,我们证明了这类席夫碱中间体中的羟基和甲基分支在稳定 BPs 方面起着重要作用。