The 2D-correlated structures of a lyotropic liquid crystalline diol with a phenylpyrimidine core
作者:Johanna R. Bruckner、Daniel Krueerke、Jan H. Porada、Stefan Jagiella、Dirk Blunk、Frank Giesselmann
DOI:10.1039/c2jm32868b
日期:——
Even though the fluid tilted smectic C (SmC) phase is one of the most common phases in thermotropic liquid crystals, the lyotropic analogue to SmC is practically unknown so far. One of the rare examples, a lyotropic liquid crystalline diol, which was reported in 1991 to show this phase, was re-examined by means of detailed X-ray diffraction and polarised optical microscopy. Although the diol possesses a smectic C promoting phenylpyrimidine core, it was not possible to verify the existence of a SmC-analogue lyotropic phase. Instead, the phase diagram shows the existence of five different lyotropic phases identified as nematic, lamellar Lα and hexagonal as well as two novel complex 2D-correlated lyophases. Results obtained by electron density calculations and X-ray diffraction data strongly suggest that the structure of one of these phases possesses a pseudo-c2mm symmetry and is built up of two different kinds of columns, whereas the other one is a ribbon phase of the oblique plane group p2.
尽管流体倾斜 Smectic C(SmC)相是各向同性热液晶中最常见的相位之一,但迄今为止,SmC 的各向同性类似物实际上还不为人所知。通过详细的 X 射线衍射和偏振光学显微镜,我们重新研究了 1991 年报道的呈现出这种相的一个罕见实例--溶胀性液晶二元醇。虽然该二元醇具有促进苯基嘧啶核心的 Smectic C,但无法验证是否存在类似 SmC 的各向同性相。相反,相图显示存在五种不同的裂解相,分别为向列相、层状 Lα 相和六方相,以及两种新型复杂的二维相关裂解相。通过电子密度计算和 X 射线衍射数据获得的结果强烈表明,其中一个相的结构具有伪 2mm 对称性,由两种不同的柱体组成,而另一个相则是斜面组 p2 的带状相。