Effect of central linkages on mesophase behavior of imidazolium-based rod-like ionic liquid crystals
作者:Xiaohong Cheng、Fawu Su、Rong Huang、Hongfei Gao、Marko Prehm、Carsten Tschierske
DOI:10.1039/c2sm06854k
日期:——
Two series of phenylbenzylether and benzanilide based rod-like imidazolium bromides and their nonionic precursors, the 1-phenyl-1H-imidazoles have been synthesized and the influence of the number and length of the alkyl chain(s) and the structure of the linking group in the aromatic core (–CH2O–, –COO–, –CONH–) on their mesophase self-assembly in ionic liquid crystalline phases were studied by POM, DSC and XRD. Upon decreasing the length of the N-terminal chain or by enlarging the number and length of the C-terminal chains, the sequence smectic (SmA)–hexagonal columnar (Colhex)–micellar cubic (CubI/Pm3n) was found for the ether based imidazolium salts; while only SmA and Colhex phases were observed for the related amides. The influence of the polarity of the central linkages, namely –CH2O– and –CONH–, on the mesophase structure and stability is discussed and compared with related –COO– connected ILC.
合成了两系列基于苯基苄醚和苯腈的棒状咪唑鎓溴化物及其非离子前体1-苯基-1H-咪唑,并研究了烷基链的数量和长度以及芳香核心中连接基团(–CH2O–、–COO–、–CONH–)的结构对其在离子液晶相中的介相自组装的影响,采用了偏光显微镜(POM)、差示扫描量热仪(DSC)和X射线衍射(XRD)等技术。当减少N-末端链的长度或增加C-末端链的数量和长度时,对于基于醚的咪唑鎓盐,发现了层状相(SmA)–六角柱状相(Colhex)–胶束立方相(CubI/Pm3n)的序列;而相关的酰胺仅观察到SmA和Colhex相。讨论了中心链接的极性(即–CH2O–和–CONH–)对介相结构和稳定性影响,并与相关的–COO–连接的离子液晶进行了比较。