Probing the Structure of Water Molecules at an Oil/Water Interface in the Presence of a Charged Soluble Surfactant Through Isotopic Dilution Studies
Technical rept. 1 Jun 97-31 May 98
OREGON UNIV EUGENE DEPT OF CHEMISTRY
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We have employed vibrational sum frequency generation VSFG to obtain the first vibrational spectra of water molecules at an oilwater interface in the presence of a charged, soluble surfactant. By examining OH stretching modes that are highly sensitive to the local hydrogen bonding environment, we have been able to compare the structure of interfacial water molecules with the structure of bulk water molecules determined from previous studies. From the VSFG spectra we infer that there is more extensive hydrogen bonding between neighboring water molecules at the CCl4water interface as compared to water molecules in the bulk aqueous phase. The presence of a charged surfactant enhances the SF response in the OH stretching spectral region in a manner similar to what we have previously observed at the airwater interface. To further probe the hydrogen bonding of water molecules at the oilwater interface we have employed VSFG to study mixed samples of H2O and D2O.
- Physical Chemistry
- Atomic and Molecular Physics and Spectroscopy