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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.
Two kinds of bowl-shaped CTV derivatives-CTV-1 and CTV-2 were synthesized by the traditional trimerization-forming method using vanillin as the raw material. The former’s peripheral groups were -OCH3 and -OCH2CH3, the latter Of the peripheral groups are -OCH3 and -OCH2COOCH3 .Two kinds of bowl-shaped CTV molecules are all thermotropic liquid crystals, which show the typical texture of nematic phase and uniform texture of single micro-region, and also observe the regular and beautiful mosaic morphology , The size of each rectangular mosaic on the order of tens of microns, repeated cooling cycle can be repeated and disappear found mosaic morphology is essentially frozen on the nematic phase crystallization and shrinkage of the decoration and shrink Optical Pattern Through the study of SEM, it is observed that the mosaic morphology is assembled by lamellae, each mosaic is a rectangular multi-lamellar lamella, and the lamellar lamellae are made of single-layer lamellae stacked directly. The constituent elements of the lamellae are microfibrils with a diameter of about 1 micron and the microfibers should be bundled bowl-shaped molecular columns. The mosaic morphology is decorated on the bowl-shaped columnar nematic phase. By this new method, s = + 1 (δ = 0 and δ = 90 °) and s = ± 1/2 A variety of point-to-point and Nèel micro-wall It is shown that the columnar columnar nematic phase has a similar liquid crystal behavior to the general nematic phase, but the basic structural unit of orientation is a bowl-shaped column or a bundle of bowl-shaped molecular columns (ie, But not the bowl-shaped molecule itself. The bowl-shaped molecular column functions as a rodlike molecule in the general nematic phase, so this article uses a new name “Bowl Columnar Nematic” To represent this different conventional nematic phase.