Deuterium NMR and molecular ordering in the cholesteryl alkanoates mesophases
Deuterium NMR and molecular ordering in the cholesteryl alkanoates mesophases
复制标题
胆固醇链烷酸酯中间相中的氘核磁共振和分子排序
DOI：
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发表时间：
1981
期刊：
影响因子：
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通讯作者：
E. Samulski
中科院分区：
文献类型：
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作者：
Z. Luz;R. Poupko;E. Samulski
近晶型、胆甾型和脂肪酸酯系列中两个成员的蓝色相的氢核磁共振。报道了正辛酸胆固醇酯和肉豆蔻酸胆固醇酯。还讨论了溶解在这些液晶中的探测分子的氢谱。测量是在63公斤(42兆赫)的频率下进行的。在这个高场下，近晶相和胆甾相都可以完全或部分地与主要垂直于磁场的指向矢对齐。计算结果提供了不同阶段的有序参数以及螺旋轴的有序过程的信息。结果表明，近晶中间相形成了良好的取向磁区，而胆甾相由两种磁区组成：(I)螺旋轴平行于磁场的均匀取向磁区和(Ii)明显具有焦点锥形织构的随机取向磁区。这两类结构域的相对丰度取决于样品的热历史和其他参数。
Deuterium NMR of the smectic, cholesteric, and the blue phases of two members of the cholesteryl alkanoate series, viz. cholesteryl nonanoate and cholesteryl myristate, are reported. Deuterium spectra of probe molecules dissolved in these liquid crystals are also discussed. The measurements were made at 63 kG (42 MHz). At this high field both the smectic and cholesteric phases can be fully or partially aligned with the director oriented predominantly perpendicular to the magnetic field. The results provide information on the order parameter in the various phases and on the ordering process of the helical axis. It is found that the smectic mesophase forms well oriented domains, but that the cholesteric phase consists of two types of domains: (i) uniformly oriented domains with the helical axis parallel to the magnetic field and (ii) randomly oriented domains apparently with focal conic texture. The relative abundance of the two types of domains depends on the thermal history of the sample and other paramet...