Shape of dielectric relaxation curves of ethylene glycol oligomer–water mixtures
Shape of dielectric relaxation curves of ethylene glycol oligomer–water mixtures
复制标题
乙二醇低聚物-水混合物的介电弛豫曲线形状
DOI：
10.1063/1.477653
复制
发表时间：
1998
影响因子：
4.4
通讯作者：
S. Yagihara
中科院分区：
文献类型：
--
作者：
N. Shinyashiki;S. Sudo;Wataru Abe;S. Yagihara
在25°C下，在100 MHz-30 GHz频率范围内对具有1-6个重复单元的乙二醇低聚物（EGO）水混合物进行了介电测量。在每种混合物中观察到一个由水和EGO引起的松弛过程。当EGO重复单元数大于3个时，水混合物呈现出宽而对称的松弛曲线。另一方面，当EGO的重复单元数小于等于2个时，混合物表现出宽且不对称的弛豫曲线。在EGO -水混合物中观察到的两种松弛曲线反映了EGO分子的大小。对于较小的EGO - water混合物，不对称弛豫曲线是由于水和EGO分子在EGO - water团簇中的协同运动。相反，对称性介电弛豫曲线是在较大的EGO-water混合物中局部结构变化的结果。较大的EGO分子不能协同移动，并对水团的运动产生几何约束。
Dielectric measurements of water mixtures of ethylene glycol oligomer (EGO) with 1–6 repeat units were carried out in the frequency range of 100 MHz–30 GHz at 25 °C. One relaxation process due to water and EGO was observed for each mixture. If the number of repeat units of EGO is larger than three, the water mixtures show a broad and symmetric relaxation curve. On the other hand, if the number of repeat units of EGO is two or less, the mixtures show a broad and asymmetric relaxation curve. The two types of relaxation curves observed in the EGO–water mixtures reflect the size of the EGO molecule. The asymmetric relaxation curve is due to the cooperative motion of water and EGO molecules in the EGO–water cluster for smaller EGO–water mixtures. In contrast, the symmetric dielectric relaxation curve is a result of the variation of local structure in larger EGO–water mixtures. The larger EGO molecules cannot move cooperatively and behave as a geometrical constraint to the motion of water clusters.