Maeda Kousaku, Shinyashiki Naoki, Yagihara Shin, Wiegand Simone, Kita Rio
Graduate School of Science and Technology, Tokai University, Hiratsuka, 259-1292, Kanagawa, Japan,
Eur Phys J E Soft Matter. 2014 Oct;37(10):94. doi: 10.1140/epje/i2014-14094-1. Epub 2014 Oct 23.
The thermal diffusion of aqueous solutions of mono-, di-ethylene glycols, poly(ethylene glycol), methanol, and glycerol is investigated systematically as a function of concentration using the Thermal Diffusion Forced Rayleigh Scattering (TDFRS). For all investigated binary mixtures, the Soret coefficient, S(T), decays with increasing concentration of the non-aqueous component showing two regions. For aqueous solution of ethylene glycol, at a very low solute content the decay is steep, while it becomes less steep for higher solute concentration. All mixtures show a sign change of S(T) with concentration. The sign change concentration is discussed with respect to chemical structures of solute molecules and the partition coefficient, log p. It turns out that the number of hydroxyl groups plays an important role. For the investigated aqueous mixtures, we find empirical linear relations between the sign change concentration and the ratio of the number of hydroxyl groups to the number of carbon atoms as well as the partition coefficient, log p.
利用热扩散强迫瑞利散射（TDFRS）系统地研究了单乙二醇、二乙二醇、聚乙二醇、甲醇和甘油水溶液的热扩散随浓度的变化情况。对于所有研究的二元混合物，索雷特系数S(T)随着非水组分浓度的增加而衰减，呈现出两个区域。对于乙二醇水溶液，在溶质含量非常低时衰减陡峭，而在溶质浓度较高时衰减变得不那么陡峭。所有混合物的S(T)都随浓度发生符号变化。根据溶质分子的化学结构和分配系数log p对符号变化浓度进行了讨论。结果表明，羟基的数量起着重要作用。对于所研究的含水混合物，我们发现符号变化浓度与羟基数量与碳原子数量之比以及分配系数log p之间存在经验线性关系。
