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Study on dynamic interaction of nematogen and polymer by means of hererodyne light scattering method

外差光散射法研究线虫与聚合物的动态相互作用

基本信息

批准号：
15540390
负责人：
MASTOKA Tatsuro
金额：
$ 1.79万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

In recent years, extensive studies on the phase transition behaviors of mixtures of liquid crystals and polymers have been carried out. Little studies, however, have been performed on the dynamics. Since the dimension of the polymer molecules are much larger than that of liquids crystal molecules, it is very interesting how the addition of polymer affects the reorientational and translational behavior of liquid crystal in the polymer and liquid crystal mixtures.In this study, the power spectra of the polarized and depolarized light scattering were obtained by means of the light scattering method based on an optical heterodyne technique. The reorientational relaxation time and the constant attributed to the coupling between reorientational and translational modes of molecular motions in anisotropic molecules, R, were obtained from the polarized and depolarized spectra in the mixture of polystyrene(PS) and 4-cyano-4'-pentyl biphenyl (5CB) in the isotropic phase. We also measured the intrinsic viscosity to study the miscibility of PS in the mixturesLarge influence was observed when the molecular weight of PS is small and the value of R largely decreases with increasing PS concentration when the temperature is near the phase transition point. The intrinsic viscosity for the mixtures for small molecular weight PS increases when temperature decreases to the near the phase transition points. This indicate that miscibility increases when temperature decreases to the near the phase transition points. The good miscibility leads to the large influence on the reorientational relaxation time and R.Little influence was observed on the reorientational relaxation time and R when the molecular weight of PS is large. The intrinsic viscosity of the mixtures for large molecular weight indicates that the 5CB is a poor solvent for PS. This leads to the little influence when the molecular weight of PS is large.

近年来，人们对液晶和聚合物混合物的相变行为进行了广泛的研究。然而，对动力学的研究却很少。由于聚合物分子的尺寸远大于液晶分子的尺寸，因此聚合物的添加如何影响聚合物和液晶混合物中液晶的重新取向和平移行为是非常有趣的。本研究通过基于光学外差技术的光散射方法获得了偏振和去偏振光散射的功率谱。从各向同性相中聚苯乙烯（PS）和4-氰基-4'-戊基联苯（5CB）混合物的偏振和去偏振光谱中获得了各向异性分子中分子运动的重新取向和平移模式之间耦合的重新取向弛豫时间和常数R。我们还测量了特性粘度来研究 PS 在混合物中的混溶性。当 PS 分子量较小时，观察到影响较大，并且当温度接近相变点时，R 值随着 PS 浓度的增加而大幅降低。当温度降低到接近相变点时，小分子量 PS 混合物的特性粘度增加。这表明当温度降低到相变点附近时，混溶性增加。良好的混溶性导致对再取向弛豫时间和R的影响较大。当PS分子量较大时，对再取向弛豫时间和R的影响较小。大分子量混合物的特性粘度表明5CB是PS的不良溶剂。这导致PS分子量较大时影响较小。