波谱学杂志 ›› 2005, Vol. 22 ›› Issue (3): 253-259.

• 研究论文 • 上一篇    下一篇

嵌段共聚物溶致液晶相中水的2H-NMR动力学分析

  

  1. 南开大学、天津大学联合研究院 1.南开大学 物理系;2.吸附分离功能高分子材料重点实验室;3.南开大学 化学系,天津 300071
  • 收稿日期:2005-04-11 修回日期:2005-06-05 出版日期:2005-09-05 发布日期:2005-09-05
  • 基金资助:

    国家自然科学基金资助项目(20474034,20374031, 20373029,20274020);教育部南开大学、天津大学科技合作基金资助项目.

Dynamics of Liquid Crystalline Phases in Block Copolymers Studied by 2H-NMR Spectroscopy

  1. 1.Department of Physics; 2.Key Laboratory of Functional Polymer Materials for Adsorption and Separation,Polymer Chemistry Institute; 3.Department of Chemistry; Nankai University,Tianjin 300071
  • Received:2005-04-11 Revised:2005-06-05 Online:2005-09-05 Published:2005-09-05
  • Supported by:

    国家自然科学基金资助项目(20474034,20374031, 20373029,20274020);教育部南开大学、天津大学科技合作基金资助项目.

摘要:

采用D2O 的2H-NMR线型和弛豫分析了PEO-PPO-PEO/D2O/对二甲苯体系的层状和六角液晶相的动力学行为. 通过实验测得了两个不同体系的自旋晶格弛豫时间T1、自旋-自旋弛豫时间T22H-NMR 谱. 2H-NMR 谱均为具有四极劈裂的粉末谱线型,且在谱图的中心,βLD=54.7°时存在一个倒峰. 倒峰的出现直接表明引起体系中弛豫的主要动力学过程处于极窄化区域. 采用NMR弛豫模型,通过调节动力学参数,使理论模拟的2H-NMR谱、弛豫时间、倒峰的大小与实验的对应量相吻合,求得了体系的动力学参数.

关键词: NMR, 动力学行为, 2H-NMR谱线型和弛豫, 嵌段共聚物, NMR弛豫模型, 液晶相

Abstract:

The dynamic behaviors of the lamellar and hexagonal liquid crystalline phases of PEO-PPO-PEO/D2O/p-xylene composite were studied by 2H NMR spectroscopy. 2H powder spectra and 2H spin-lattice and spinspin relaxation times were measured in two samples with different compositions. All spectra showed powder lineshape with quadrupole splitting and a reversed peak at the center when βLD=54.7°, indicating that the dominant dynamic process that modulates the quadrupole interaction is in the extreme narrowing region. Dynamic parameters of the studied systems were obtained by fitting the experimentally measured 2H spectra, spin-lattice and spin-spin relaxation times and the intensity of the reversed peak to a theoretical NMR relaxation model.

Key words: 2H NMR, block copolymer, dynamics, powder lineshape, relaxation, liquid crystalline phase

中图分类号: