Interaction between Hydrophobically Modified 2-Hydroxyethyl Cellulose and Sodium Dodecyl Sulfate Studied by Viscometry and Two-Dimensional NOE NMR Spectroscopy

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• 作者：Jen-Ting Lo ; Hsiao-Ting Yen ; Chih-Chang Tsai ; Bing-Hung Chen ; Sheng-Shu Hou
• 刊名：Journal of Physical Chemistry B
• 出版年：2014
• 出版时间：June 19, 2014
• 年：2014
• 卷：118
• 期：24
• 页码：6922-6930
• 全文大小：474K
• 年卷期：v.118,no.24(June 19, 2014)
• ISSN：1520-5207

文摘

Interaction between an anionic surfactant, sodium dodecyl sulfate (SDS), and a nonionic polymer, 2-hydroxyethyl cellulose (HEC) hydrophobically modified with benzoyl chloride (bmHEC), is studied by viscometry and two-dimensional nuclear Overhauser effect NMR spectroscopy (2D NOESY) in a semidilute regime of bmHEC. The hydrophobicity of bmHEC was varied with different substitution of benzoyl group to HEC macromolecules. In general, the low-shear viscosity of 1 wt % bmHEC aqueous solution is increased with added SDS surfactant having concentration from 0 to 0.5 wt %, and then decreased significantly with a further addition of surfactant to 3 wt %. The activation energy of transient network formation in 1 wt % bmHEC aqueous solution present with SDS surfactant is found to be dependent with SDS concentration, which varies from 32.7 to 69.80 kJ/mol. The maximum activation energy takes place when 0.5 wt % SDS is added, which coincides with that of the maximal viscosity. The 2D NOESY displays that the surfactants actually interact with bmHEC not only on the hydrophobes, namely benzoyl groups, but also the polymer backbone, i.e., glucose units. In contrast, no interaction is revealed by 2D NOESY in the aqueous system containing SDS surfactant and HEC polymer.