Liquid crystal character controlled by complementary discotic molecules mixtures： Columnar stacking type and mesophase temperature range

• Published in: Chinese chemical letters Vol. 27; no. 3; pp. 475 - 480
• Main Authors: Li, Yan, Li, Ming-Guang, Su, Ya-Jun, Liu, Jian-Gang, Han, Yan-Chun, Zheng, Shi-Jun, Wang, Li-Xiang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2016
• Subjects: Alkyl chains packing; Liquid crystals; Mesophase type; Mixture; Phase transitions; 中间相; 互补; 分子结构; 柱状相; 液晶特性; 混合物; 温度范围; 盘状; Mesophase type; Liquid crystals; Phase transitions; Alkyl chains packing; Mixture
• ISSN: 1001-8417; 1878-5964
• DOI: 10.1016/j.cclet.2015.12.024

In this work, the mesophase properties were tuned via mixing two discotic molecules with structural complementarity. Compared with the liquid crystalline hexakis（n-hexyloxy）triphenylene（H6TP）materials（columnar hexagonal phase from 53 ℃ to 91 ℃）, mesophase types as well as phase transition temperatures varied with the introduction of crystalline hexaazatriphenylene derivative（PBH）molecules. The introduction of less than 33% amount of PBH disrupted the columnar hexagonal phase formed by H6 TP remarkably, followed by the decreased clearing temperatures of liquid crystals. As the PBH amount was further increased, the destroyed columnar hexagonal phase was turned into the columnar rectangular phase, in which H6 TP and PBH molecules together formed the columnar mesophase. The formation of new mesophase contributed to the enlarged mesophase temperature（from44 ℃ to 144 ℃）. We speculated that the alkyl chains interaction induced by the PBH component competed with the strong p–p stacking between H6 TP molecules, thus altering the liquid crystalline properties including mesophase types and phase transition temperatures.