Influence of Flexible Spacers on Liquid-Crystalline Self-Assembly of T-Shaped Bolaamphiphiles
作者:Xiaohong Cheng、Feng Liu、Xiangbing Zeng、Goran Ungar、Jens Kain、Siegmar Diele、Marko Prehm、Carsten Tschierske
DOI:10.1021/ja200822z
日期:2011.5.25
bolaamphiphiles composed of a biphenyl rigid core, a semiperfluorinated lateral chain, two polar 1,2-diol groups in the terminal positions and flexible alkyl spacers connecting the polar groups with the biphenyl core have been synthesized and investigated by polarizing microscopy, DSC and X-ray scattering. The influence of spacer length and position of the spacer on the self-assembly in liquid-crystalline phases
合成了由联苯刚性核、半全氟侧链、末端位置的两个极性 1,2-二醇基团和连接极性基团与联苯核的柔性烷基间隔基组成的 T 形双亲分子,并通过偏光显微镜、DSC 进行了研究和 X 射线散射。研究了间隔物长度和间隔物位置对液晶相自组装的影响。一系列四种不同的柱状相(Col(hex)/p6mm、Col(rec)/p2gg、Col(squ)/p4gm 和 Col(squ)/p4mm),代表由具有六边形、五边形的圆柱体组成的液晶蜂窝结构和方形横截面,发现增加间隔长度。还表明,在 T 形双亲分子骨架中引入脂肪族间隔物用由方柱体组成的 Col(squ)/p4mm 相取代了由菱形柱体组成的 Col(rec)/c2mm 相。它还导致五边形圆柱的 2d 晶格将对称性从 Col(rec)/p2gg 增加到 Col(squ)/p4gm。首次观察到这两个五边形圆柱结构之间的温度相关的二阶相变。除了对圆柱体形状和相对称性