用马赛克形貌装饰法研究碗形分子柱状向列相的向错和分子指向矢分布

发布时间：2018-06-12 07:58

本文选题：CTV碗形分子 + 热致液晶　；参考：《中国科学(B辑:化学)》2009年01期

【摘要】：选用香兰素为原料,采用传统的三聚成环法,合成了两种碗形CTV系衍生物——CTV-1和CTV-2,前者的外围基团是—OCH3和—OCH2CH3,后者的外围基团是—OCH3和—OCH2COOCH3.两种碗形CTV分子均是热致液晶,呈现向列相典型的粒状织构和单微区的均匀织构,还观察到规则美观的马赛克形貌,每块矩形马赛克的尺寸为数十微米数量级,多次升降温循环能重复出现和消失.发现马赛克形貌实质上是在冻结的向列相织构上结晶化并收缩龟裂而装饰出来的光学图案.通过扫描电镜的研究,观察到马赛克形貌是由片晶组装而成的,每块马赛克就是一块矩形的多层片晶,多层片晶由单层片晶堆积而成.直接观察到片晶的组成单元是直径约1微米的微纤,而微纤应当是束状的碗形分子柱.马赛克形貌装饰在碗形分子柱状向列相上,通过这种新方法观察到s=+1(δ=0和δ=90°)和s=±1/2多种点向错和Nèel微区壁等周围的分子指向矢分布情况.说明碗形分子柱状向列相与一般向列相有类似的液晶行为,但取向的基本结构单元是碗形分子柱,或者由碗形分子柱组成的束(即微纤),而不是碗形分子本身.碗形分子柱起了一般向列相中棒状分子的作用,所以本文以一个新名称"碗形分子柱状向列相"BCN(Bowlic Columnar Nematic)来表示这种不同常规的向列相.
[Abstract]:Two kinds of bowl-shaped CTV derivatives, CTV-1 and CTV-2, were synthesized by using vanillin as raw material. The outer groups of the former were -OCH3 and -OCH2CH3, and the latter were -OCH3 and -OCH2COOCH3. The two kinds of CTV molecules are thermotropic liquid crystals with typical nematic granular texture and uniform texture of single microregion. Regular and beautiful mosaic morphology is also observed. The size of each rectangular mosaic is tens of microns. Multiple cycles of rising and cooling can reappear and disappear. It is found that the mosaic morphology is essentially an optical pattern decorated by crystallization and shrinkage on frozen nematic texture. The morphology of the mosaic was observed by SEM. Each mosaic is a rectangular multilayer crystal, and the multilayer lamellar crystal is formed by a monolayer wafer. It is observed directly that the component unit of the wafer is a microfiber about 1 micron in diameter, and the microfiber should be a bundle of bowl-shaped molecular columns. The mosaic morphology is decorated on the columnar nematic phase of the bowl-shaped molecule. The distribution of the molecular direction vector around S = 1 (未 -0 and 未 _ (90 掳) and S = 卤1 / 2 and the wall of N 猫 el microregion is observed by this new method. The results show that the columnar nematic phase of the dish-shaped molecule has a liquid crystal behavior similar to that of the general nematic phase, but the basic structural unit oriented is the dish-shaped molecular column, or the beam (i.e. the micro-fiber, not the bowl-shaped molecule itself) composed of the dish-shaped molecular column. The bowl-shaped molecular column acts as a bar molecule in the general nematic phase, so a new name, BCN-Bowlic columnar nematic, is used to express this different conventional nematic phase.
【作者单位】：厦门大学材料学院材料科学与工程系;
【基金】：国家自然科学基金基金(批准号:20774077) 福建省自然科学基金(E0510003) 厦门市科技计划项目(3502Z20055013)资助
【分类号】：O641.4

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