Dielectric study of the α and β processes in supercooled ethylene glycol oligomer–water mixtures
Dielectric study of the α and β processes in supercooled ethylene glycol oligomer–water mixtures
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DOI：
10.1063/1.1796232
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发表时间：
2004-10
影响因子：
4.4
通讯作者：
S. Sudo;S. Tsubotani;Mayumi Shimomura;N. Shinyashiki;S. Yagihara
中科院分区：
文献类型：
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作者：
S. Sudo;S. Tsubotani;Mayumi Shimomura;N. Shinyashiki;S. Yagihara
在10 μHz ~ 10 GHz频率范围和128-298 K温度范围内，对65 wt %乙二醇低聚物（EGO）-水混合物（含有1 ~ 6个EGO分子重复单元）进行了宽带介电测量。在具有一个和两个重复单元的EGO分子（小EGO）的水-EGO混合物的情况下，初级过程的介电损耗峰的形状关于在交叉温度TC以上的最大损耗频率的对数是不对称的。非对称过程在低频率处延续到α过程，在TC以下高于α过程的频率范围内出现额外的β过程。相比之下，具有三个或更多个EGO分子重复单元的水-EGO混合物（大EGO）显示出TC以上的主要过程的宽且对称的损失峰。对称过程延续到β过程，在TC以下比β过程低的频率范围内，又出现了一个额外的α过程。这些不同的场景…
Broadband dielectric measurements for 65 wt % ethylene glycol oligomer (EGO)–water mixtures with one to six repeat units of EGO molecules were performed in the frequency range of 10 μHz–10 GHz and the temperature range of 128–298 K. In the case of the water-EGO mixtures with one and two repeat units of the EGO molecule (small EGO), the shape of the dielectric loss peak of the primary process is asymmetrical about the logarithm of the frequency of maximum loss above the crossover temperature, TC. The asymmetric process continues to the α process at a low frequency, and an additional β process appears in the frequency range higher than that of the α process below TC. In contrast, the water-EGO mixtures with three or more repeat units of the EGO molecule (large EGO) show a broad and symmetrical loss peak of the primary process above TC. The symmetric process continues to the β process, and an additional α process appears in the frequency range lower than that of the β process below TC. These different scenar...