Hamaker Constants of Iron Oxide Nanoparticles
| Autor: | Bertrand Faure, German Salazar-Alvarez, Lennart Bergström |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Stereochemistry
Iron oxide Maghemite Dielectric engineering.material chemistry.chemical_compound symbols.namesake Electrochemistry General Materials Science Colloids Magnetite Nanoparticles Spectroscopy Magnetite Silicon Compounds Surfaces and Interfaces Hematite Silicon Dioxide Condensed Matter Physics chemistry visual_art visual_art.visual_art_medium symbols engineering Physical chemistry van der Waals force Iron oxide nanoparticles Superparamagnetism |
| Zdroj: | Langmuir. 27:8659-8664 |
| ISSN: | 1520-5827 0743-7463 |
| DOI: | 10.1021/la201387d |
| Popis: | The Hamaker constants for iron oxide nanoparticles in various media have been calculated using Lifshitz theory. Expressions for the dielectric responses of three iron oxide phases (magnetite, maghemite, and hematite) were derived from recently published optical data. The nonretarded Hamaker constants for the iron oxide nanoparticles interacting across water, A(1w1) = 33 - 39 zJ, correlate relatively well with previous reports, whereas the calculated values in nonpolar solvents (hexane and toluene), A(131) = 9 - 29 zJ, are much lower than the previous estimates, particularly for magnetite. The magnitude of van der Waals interactions varies significantly between the studied phases (magnetitemaghemitehematite), which highlights the importance of a thorough characterization of the particles. The contribution of magnetic dispersion interactions for particle sizes in the superparamagnetic regime was found to be negligible. Previous conjectures related to colloidal stability and self-assembly have been revisited on the basis of the new Lifshitz values of the Hamaker constants. |
| Databáze: | OpenAIRE |
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