圧力ジャンプを用いた高分子液体の動的階層構造の研究

在这个项目中，我们重点研究了动态不对称二元混合物中浓度涨落的相分离和/或松弛过程中的粘弹性效应。利用时间分辨小角中子散射法研究了动态非对称聚合物共混物在压力快速变化下浓度起伏的驰豫过程。压力变化是在单相共混物中进行的，该池是为高温高压下的聚合物体系设计的。在弛豫过程中，散射强度分布随波数(Q)的时间变化符合Cahn-Milliard-Cook线性化理论。理论分析得到了Onsager运动系数的Q依赖关系，在QξVe和Gt；1处表现为Q^lt；-2&gt；-依赖，特征长度ξVe远大于dAb或pI的回转半径.估算的ξVe与用DOI和Onuki理论计算的结果吻合得很好，后者考虑了组分聚合物之间的动力学不对称性在浓度涨落松弛过程中产生的粘弹性效应

In this project, we focus on the viscoelastic effects during the phase separation and/or the relaxation process 'of the concentration fluctuations in dynamically asymmetric binary mixtures. In particular, we found the following : Relaxation processes of the concentration fluctuations induced by a rapid pressure change were investigated for a dynamically asymmetric polymer blend by using time-resolved small angle, neutron scattering. The pressure change was carried out inside the single phase blend with the cell designed for polymeric systems under high pressure and high temperature. Time change in the scattered intensity distribution with wave number (q) during the relaxation processes was found to be approximated by Cahn-Milliard-Cook linearized theory. The theoretical analysis yielded the q-dependence of Onsager kinetie coefficient which is characterized by the q^<-2>-dependence at qξve >1 with the characteristic length ξve being much larger than radios of gyration of DAB or PI. The estimated ξve agrees' well with that calculated using Doi and Onuki theory which takes into account the viscoelastic effects arising from the dynamical asymmetry between the component polymers in the relaxation of concentration fluctuations