Disclination and molecular director studies on bowlic columnar nematic phase using mosaic-like morph

来源 :Science in China(Series B:Chemistry) | 被引量 : 0次 | 上传用户:whatisbianbian01
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
Two bowlic cyclotriveratrylene CTV-1 and CTV-2, with different peripheral groups of -OCH3 and -OCH2CH3 for CTV-1 and -OCH3 and -OCH2COOCH3 for CTV-2, respectively, were synthesized by typical trimerization via a multistep sequence from vanillin. Both bowlic CTV molecules were thermotropic liquid crystals, and presented typical grainy textures of the nematic phase and homogeneous texture of the single domain nematic phase. It is of interest to observe the regular and beautiful mosaic-like morphologies after cooling from liquid crystalline phases, which appeared and vanished repeatedly in several circles of cooling and heating. The size of each mosaic was several dozens of micron. In nature, the mosaic-like morphologies are the optical pattern of cracks formed by the shrinking, due to the crystallization of frozen texture of nematic phases. By means of scanning electron microscopy, the mosaic-like morphologies were observed to consist of lamellae, and each mosaic is a rectangular multi-layer lamella, which is composed of packed single-layered lamellae. The fibrils in the diameter of about 1 μm were observed, which are the structural units of lamellae and would be the bundles of the bowlic molecular columns. The mosaic-like morphologies decorate the bowlic molecular columnar nematic phase, therefore, a novel mosaic-like morphologies decoration method was applied to reveal the director distribution of several kinds of point disclinations, such as s = +1(δ =0°and δ =90°) and s = ±1/2, and Nèel domain walls. It was shown that the bowlic molecular columnar nematic phase behaved as normal nematic phases; however, the basic structural units ordered were the bowlic molecular column or the bundles of bowlic molecular column (i.e. fibrils), but not the bowlic molecules themselves. The bowlic molecular columns acted as the rod-like molecules in a normal nematic phase. Therefore, a new term BCN (bowlic columnar nematic phase) is used to describe the anomalous nematic phase in this paper. Two bowlic cyclotriveratrylene CTV-1 and CTV-2, with different peripheral groups of -OCH3 and -OCH2CH3 for CTV-1 and -OCH3 and -OCH2COOCH3 for CTV-2, respectively, were synthesized by typical trimerization via a multistep sequence from vanillin. Both bowlic CTV molecules were thermotropic liquid crystals, and presented typical grainy textures of the nematic phase and homogeneous texture of the single domain nematic phase. It is of interest to observe the regular and beautiful mosaic-like morphologies after cooling from liquid crystalline phases, which The nature of the mosaic-like morphologies are the optical pattern of cracks formed by the shrinking, due to the crystallization of frozen texture of nematic phases. By means of scanning electron microscopy, the mosaic-like morphologies were observed to consist of lamellae, and each mosaic is a rectangular multi-l ayer lamella, which is composed of packed single-layered lamellae. The fibrils in the diameter of about 1 μm were observed, which are the structural units of lamellae and would be the bundles of the bowlic molecular columns. The mosaic-like morphologies decorate the bowlic molecular columnar nematic phase, therefore, a novel mosaic-like morphologies decoration method was applied to reveal the director distribution of several kinds of point disclinations, such as s = +1 (δ = 0 ° and δ = 90 °) and s = ± 1/2, and Nèel domain walls. It was shown that the bowlic molecular columnar nematic phase behaved as normal nematic phases; however, the basic structural units ordered were the bowlic molecular column or the bundles of bowlic molecular columns (ie fibrils) but not the bowlic molecules themselves. The bowlic molecular columns acted as the rod-like molecules in a normal nematic phase. Thus, a new term BCN (bowlic columnar nematic phase) is used to describe the anomalous nematic phase in this paper.
其他文献
5月12日,8级大地震。汶川天崩地裂,四川地动山摇。顷刻间,数万生灵遭涂炭,美丽城乡变废墟。琅琅书声,戛然而止;吟吟笑语,瞬间逝去。江河呜咽,天地同哀。大灾大难,见证党的执
AIM:To investigate the inhibitory effect of acetylshikonin on human gastric carcinoma cell line SGC-7901 and its mechanism. METHODS:MTT assay was used to assess
A desmoplastic small round cell tumor (DSRCT) is a rare, aggressive mesenchymal neoplasm. Although a DSRCT can develop at various sites, the intraabdominal site
20世纪20年代末,左翼戏剧运动逐渐成为中国现代话剧的主潮。苏联话剧《怒吼吧,中国!》与中国现实紧密相连,得到了田汉、陶晶孙、欧阳予倩、徐懋庸、胡愈之、董每戡、茅盾、郑
目的 评估北京地区限定人群为基础的视盘出血和萎缩弧的发生率.方法对参与眼病筛查的具有清晰眼底照片的4163人,4163只右眼(男/女=1832/2331)的眼底照片进行视盘出血和萎缩弧的评估.结果青光眼在人群中的发病率为3.0%(135/4439), 视盘出血在人群中的发生率为1.0%(42/4163), 其中女性为多,且有随年龄增加出血人数逐渐增加的趋势.视盘出血多见于青光眼,而少见于正常人群(
Through rigorous natural selection, biological organisms have evolved exceptional functions highly adaptable to their living environments. Biological organisms
11月12日,上海贝尔阿尔卡特与英特尔宣布签署“谅解备忘录”,在中国合作开发和推广基于Linux 环境的移动网络应用方案。在该备忘录的框架下,上海贝尔阿尔卡特与 Intel 将利
8月18日获悉长城电脑和神州数码推出,合作之后研发的第一款电脑产品——长城“世恒8000”系列。世恒8000和IBM 整机在长城电脑公司的同一条生产线生产,并通过国家3C 认证。
达到怎样的标准,才能称得上是科学发展示范单位?对基层创建科学发展示范单位工作,应该依据哪些具体指标进行考评?今年5月,唐山市路北区在全市率先出台创建科学发展示范单位评
国产动画历来是中国影视领域的软肋,但今年似乎出现了全新改变。据统计,截至6月30日,上半年国内一共上映了15部国产动画,总票房突破4亿元,相较2012年上半年的2.9亿元,增长幅