Soret Effect of n-Octyl β-D-Glucopyranoside (C8G1) in Water around the Critical Micelle Concentration
Soret Effect of n-Octyl β-D-Glucopyranoside (C8G1) in Water around the Critical Micelle Concentration
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DOI：
10.1021/jp907988r
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发表时间：
2010-02-18
影响因子：
3.3
通讯作者：
Wiegand, Simone
中科院分区：
文献类型：
--
作者：
Arlt, Bastian;Datta, Sascha;Wiegand, Simone
我们研究了非离子表面活性剂C（8）G（1）（n-辛基β-D-吡喃葡萄糖苷）在水中的热扩散行为，在T = 15至60 ℃的温度范围内，在w = 0.25wt%和w = 2.0wt%之间的不同浓度。本文的目的是研究表面活性剂体系在临界胶束浓度（cmc）附近的热扩散行为，临界胶束浓度是由表面张力测量独立确定的。在经典的TDFRS中，表面活性剂溶液在吸光染料的存在下显示出在cmc处的热扩散系数（D-T）和Soret系数（S-T）的显著变化。这一结果与最近的热透镜研究一致[桑托斯等人，Phys.Rev.E2008，77，011403]，其还显示在染料存在下CMC周围的热透镜物质信号的显著变化。我们发现，如果没有染料或使用不被染料吸收的光源，这种变化变得不那么明显。在较高的浓度下，我们观察到的温度依赖性的符号变化的S-T也已被发现在较高浓度的硬球的解决方案。
We studied the thermal diffusion behavior of the nonionic surfactant C(8)G(1) (n-octyl beta-D-glucopyranoside) in water for different concentrations between w = 0.25 wt% and w = 2.0 wt% in a temperature range from T = 15 to 60 degrees C using the classical and infrared thermal diffusion forced Rayleigh scattering (TDFRS) setup. The purpose of the present paper is the investigation of the thermal diffusion behavior of surfactant systems around the critical micelle concentration (cmc), which is independently determined by surface tension measurements. In the classical TDFRS, the surfactant solutions show in the presence of alight-absorbing dye a pronounced change of the thermal diffusion coefficient (D-T) and the Soret coefficient (S-T) at the cmc. This result agrees with a recent thermal lens study [Santos et al., Phys. Rev. E 2008, 77, 011403], which also showed in the presence of dye a pronounced change of the thermal lens matter signal around the cmc. We found that this change becomes less pronounced, if the dye is absent or a light source is used, which is not absorbed by the dye. At higher concentrations, we observed a temperature-dependent sign change of S-T as has also been found for solutions of hard spheres at higher concentrations.