Dielectric study of water structure in polymer solution
Dielectric study of water structure in polymer solution
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聚合物溶液中水结构的介电研究
DOI：
10.1021/j100102a028
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
S. Mashimo
中科院分区：
文献类型：
--
作者：
N. Shinyashiki;Y. Matsumura;N. Miura;S. Yagihara;S. Mashimo
用时间域反射仪对聚乙烯吡咯烷酮(PVP)-水混合物进行的介电测量表明，由于水分子的重新取向，其介电行为发生了弛豫过程。如果PVP的浓度低于57wt%，混合物在0到-19℃之间冻结，松弛强度在该点下降，并在-57℃完全消失。另一方面，浓度高于57wt%的混合物没有凝固点。这些结果表明，混合物中存在三种水。第一种是在冰点消失，和纯净水一样。第二个在-57℃消失，形成一个由五个水分子和一个PVP重复单元组成的扭曲团簇。第三种没有凝固点，在高分子链之间形成无序结构。
Dielectric measurement using the time domain reflectometry made on poly (vinylpyrrolidone)(PVP)-water mixtures exhibits a relaxation process due toreorientation of water molecules. If the concentration of PVP is lower than 57 wt%, the mixture freezes between 0 and—19 C. Relaxation strength drops at that point and disappears altogether at-57 C. On the other hand, mixtures with concentration higher than57 wt% have no freezing point. These results indicate the existence of three kinds of water in the mixture. The first one, disappearing at the freezing point, is the same as pure water. The second one, which disappears at—57 C, forms a distorted cluster consisting of five water molecules and a repeat unit of PVP. The third one, which has no freezing point, forms a nonordered structure among polymer chains.