Confinement or the Nature of the Interface? Dynamics of Nanoscopic Water
| Autor: | D. B. Spry, Nancy E. Levinger, Michael D. Fayer, David E. Moilanen |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Time Factors
Spectrophotometry Infrared Cyclohexane Ionic bonding Infrared spectroscopy Photochemistry Biochemistry Micelle Article Catalysis Polyethylene Glycols Surface-Active Agents chemistry.chemical_compound Colloid and Surface Chemistry Pulmonary surfactant Cyclohexanes Hexanes Molecule Nanoscopic scale Micelles Dioctyl Sulfosuccinic Acid Chemistry Hydrogen bond Phenyl Ethers Water General Chemistry Octanes Nanostructures Solutions Chemical physics Anisotropy Hydrogen |
| Zdroj: | Journal of the American Chemical Society. 129:14311-14318 |
| ISSN: | 1520-5126 0002-7863 |
| DOI: | 10.1021/ja073977d |
| Popis: | The dynamics of water confined in two different types of reverse micelles are studied using ultrafast infrared pump-probe spectroscopy of the hydroxyl OD stretch of HOD in H2O. Reverse micelles of the surfactant Aerosol-OT (ionic head group) in isooctane and the surfactant Igepal CO 520 (non-ionic head group) in 50/50 weight percent cyclohexane/hexane are prepared to have the same diameter water nanopools. Measurements of the IR spectra and vibrational lifetimes show that the identity of the surfactant head groups affects the local environment experienced by the water molecules inside the reverse micelles. The orientational dynamics (time dependent anisotropy), which is a measure of the hydrogen bond network rearrangement, is very similar for the confined water in the two types of reverse micelles. The results demonstrate that confinement by an interface to form a nanoscopic water pool is a primary factor governing the dynamics of nanoscopic water rather than the presence of charged groups at the interface. |
| Databáze: | OpenAIRE |
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