Chinese Journal of Magnetic Resonance ›› 2005, Vol. 22 ›› Issue (3): 253-259.

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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.

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

CLC Number: