作者:Paul H. J. Kouwer、Stephen J. Picken、Georg H. Mehl
DOI:10.1039/b707880c
日期:——
A series of disc-shaped liquid crystals, monomers and dimers, have been investigated. A spacer linked to the pentakis(phenylethynyl)phenoxy core of the mesogens was substituted with perfluorinated chains to investigate the microphase segregating effect of such groups. The nematic phase, commonly found for these mesogens, is strongly stabilised by the presence of the fluorinated groups. X-Ray diffraction studies indicate clearly the onset of nanophase segregation in the nematic phase. Remarkable is the result, that the nanophase segregation directs the systems towards a lamellar organisation, rather than the columnar order that is commonly found for disc-shaped mesogens. This is also confirmed by the order in the underlying crystalline phase. X-Ray diffraction studies of the nematic phase show the characteristics of cybotactic smectic clustering, which has not been observed for discotic systems so far.
对一系列圆盘状液晶、单体和二聚体进行了研究。用全氟链取代了与中间体的五(苯乙炔基)苯氧基核心相连的间隔物,以研究这些基团的微相分离效应。氟化基团的存在极大地稳定了这些介聚物常见的向列相。X 射线衍射研究清楚地表明,向列相中开始出现纳米相分离。值得注意的是,纳米相分离将系统引向了片状组织,而不是圆盘状介质中常见的柱状秩序。底层结晶相的有序性也证实了这一点。对向列相进行的 X 射线衍射研究显示了线状聚类的特征,这是迄今为止在盘状介质系统中尚未观察到的。