扭曲曲液晶相和分子结构:甲氧基的作用
Calum J Gibb1, Magdalena M Majewska2, Grant J Strachan2
1Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Meston Building, Aberdeen, AB24 3UE, UK. c.j.gibb@leeds.ac.uk.
Physical chemistry chemical physics : PCCP
|March 5, 2025
概括
该研究报告了新的液晶材料,MeOB6OIBeOm,表现出阴性 (N) 和扭曲阴性 (NTB) 阶段. 过渡温度取决于链条长度,这表明形状驱动的NTB阶段形成.
科学领域:
- 材料科学 材料科学 材料科学
- 有机化学 有机化学
- 物理化学 物理化学
背景情况:
- 液晶表现出各种不同的中相,这对于显示技术至关重要.
- 扭曲曲阴性 (NTB) 阶段是最近发现的一种阶段,具有独特的特性.
- 液晶中的结构性质关系是设计新材料的关键.
研究的目的:
- 为了合成和描述一系列的4-[{[4-]{6-[4-]4-甲基基]基]基}氧基) 基]甲基基}氨基]基4-基基酸盐 (MeOB6OIBeOm).
- 为了研究终端基氧链长度 (m=1-10) 对液晶相态行为的影响.
- 为了比较MeOB6OIBeOm系列的过渡性行为与相关的蓝二 (CB6OIBeOm) 二次体.
主要方法:
- 合成了MeOB6OIBeOm液晶系列的合成.
- 差分扫描热量计 (DSC) 用于热分析.
- 极化光学显微镜 (POM) 用于相位表征.
主要成果:
- 所有十种MeOB6OIBeOm化合物都表现出常规的阴性 (N) 阶段.
- 在冷却后观察到m=1-9的扭曲曲阴性 (NTB) 阶段.
- 过渡温度 (N-I和NTB-N) 随着终端链长度的增加而下降.
- 在NTB-N过渡主要是形状驱动,受灵活的间隔长度和平价的影响.
- 在MeOB6OIBeOm系列中,缺乏在CB6OIBeOm系列中看到的斑纹多态.
- 对于CB6OIBeOm,N-I过渡温度更高,而NTB-N过渡温度在两个系列之间是相似的.
结论:
- 终端基链的长度显著影响N和NTB相变温度.
- NTB阶段形成主要由分子形状和灵活的间隔器特性来决定.
- 在MeOB6OIBeOm中缺少 smectic 多态性表明,蓝基核通过反平行关联促进了 smectic 行为.
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