Interaction between hydrophobically modified 2-hydroxyethyl cellulose and sodium dodecyl sulfate studied by viscometry and two-dimensional NOE NMR spectroscopy.
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.
Department of Chemical Engineering, National Cheng Kung University , 1 University Road, Tainan 70101, Taiwan.
Jen-Ting
JT
Lo
Hsiao-Ting
HT
Yen
Chih-Chang
CC
Tsai
Bing-Hung
BH
Chen
Sheng-Shu
SS
Hou
D001565:Benzoates / Q000737:chemistry; D002482:Cellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D004951:Esterification; D057927:Hydrophobic and Hydrophilic Interactions; D009682:Magnetic Resonance Spectroscopy; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry; D014783:Viscosity; D014867:Water / Q000737:chemistry
D001565:Benzoates; D013501:Surface-Active Agents; D014867:Water; D012967:Sodium Dodecyl Sulfate; D002482:Cellulose; C002283:hydroxyethylcellulose; C013409:benzoyl chloride