Dynamical structure of oligo(ethylene glycol)s-water solutions studied by time domain reflectometry
Dynamical structure of oligo(ethylene glycol)s-water solutions studied by time domain reflectometry
复制标题
时域反射法研究低聚乙二醇水溶液的动力学结构
DOI：
10.1063/1.475812
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发表时间：
1998
影响因子：
4.4
通讯作者：
R. Nozaki
中科院分区：
文献类型：
--
作者：
Takaaki Sato;H. Niwa;A. Chiba;R. Nozaki
用时域反射仪在25°C下，在300 MHz ~ 20 GHz频率范围内，测量了乙二醇200和400水溶液（聚合度N=4和9）在整个浓度区域的介电弛豫。所有样品在该频率范围内只观察到一个介电损耗峰。根据介质损耗曲线的视峰频率对乙二醇X单体摩尔分数的弛豫强度和弛豫时间的对数，在N=4时为0<X<0.35， N=9时为0<X<0.37。当N=4和N=9的浓度分别为X≈0.35和X≈0.37时，对应于1醚氧和1.7水的比例，色散和吸收曲线的形状发生了临界变化。对这些现象的分析表明，形成了1醚氧与1.7水的水化配合物，1:7 .7的配合物表现为一种组分，对应于2.7（=1+1.7）个类水分子。
Dielectric relaxation measurements on water solutions of ethylene glycol 200 and 400, (degree of polymerization N=4 and 9) in entire concentration region were carried out using a time domain reflectometry at 25 °C in the frequency range from 300 MHz to 20 GHz. For all the samples, only one dielectric loss peak was observed in this frequency range. Plots of the relaxation strength and logarithm of the relaxation time calculated from apparent peak frequency of dielectric loss curves against monomer unit molar fraction of ethylene glycol X give straight lines in the region of 0<X<0.35 for N=4, and 0<X<0.37 for N=9. Shapes of dispersion and absorption curves exhibit critical change at the concentration X≈0.35 for N=4 and X≈0.37 for N=9, corresponding to the ratio of one ether oxygen and 1.7 water. Analysis of these phenomena indicates that hydration complex of one ether oxygen and 1.7 water is formed, and the 1:1.7 complex behaves as one kind of component corresponding to 2.7(=1+1.7) waterlike molecules in th...