Pressure Dependence of the Critical Micelle Concentration of a Nonionic Surfactant in Water Studied by 1H-NMR

The critical micelle concentration (cmc) of the nonionic surfactant C8E5 in D2O was measured at 30 °C and pressures up to 350 MPa using 1H-NMR chemical shifts. The cmc was found to increase with pressure up to approximately 150 MPa and then decrease at higher pressures. This characteristic pressure...

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Bibliographic Details
Published in:Langmuir 1998-09, Vol.14 (19), p.5339-5341
Main Authors: Lesemann, Markus, Thirumoorthy, Kanthimathi, Kim, Yoo Joong, Jonas, Jiri, Paulaitis, Michael E
Format: Article
Language:English
Subjects:
Chemistry
Colloidal state and disperse state
Exact sciences and technology
General and physical chemistry
Physical and chemical studies. Granulometry. Electrokinetic phenomena
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Summary:The critical micelle concentration (cmc) of the nonionic surfactant C8E5 in D2O was measured at 30 °C and pressures up to 350 MPa using 1H-NMR chemical shifts. The cmc was found to increase with pressure up to approximately 150 MPa and then decrease at higher pressures. This characteristic pressure dependence is similar to that reported for several ionic surfactant solutions and is in quantitative agreement with the effect of pressure on the transfer of hydrocarbons from water into nonpolar solvents. We conclude, therefore, that the observed behavior is independent of the hydrophilic headgroup of the surfactant and that it reflects a pressure-induced destabilization of the hydrophobic micelle interior at low pressures and enhanced stabilization at high pressures.
ISSN:0743-7463
1520-5827
DOI:10.1021/la9805692