Phase Behavior of Magnetic Nanocolloids of Different Sizes Suspended in an Apolar Solvent
| Autor: | Martin Schoen, Dannielle G. McCarthy, Stefanie M. Wandrei |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
010304 chemical physics
Condensed matter physics Heisenberg model Chemistry Surfaces and Interfaces Hard spheres Condensed Matter Physics Radial distribution function 01 natural sciences Virial coefficient Critical point (thermodynamics) Chemical physics 0103 physical sciences Electrochemistry Magnetic nanoparticles Polar General Materials Science Density functional theory 010306 general physics Spectroscopy |
| Zdroj: | Langmuir. 33:11366-11376 |
| ISSN: | 1520-5827 0743-7463 |
| DOI: | 10.1021/acs.langmuir.7b01952 |
| Popis: | We employ classical density functional theory (DFT) to investigate the phase behavior and composition of binary mixtures; each compound consists of hard spheres of different sizes with superimposed dispersion attraction. In addition to the dispersion attraction, molecules of one component carry an additional three-dimensional magnetic "spin" where the orientation-dependent spin-spin interaction is accounted for by the Heisenberg model. We are treating the excess free energy using a modified mean-field approximation (second virial coefficient) for the orientation-dependent pair correlation function. Depending on the concentration of the magnetic particles, the strength of the spin-spin coupling, and the size ratio of the particles, the model predicts the formation of ordered (polar) phases in addition to the more conventional gas and isotropic liquid phases. Key features of our model are a particle-size dependent shift of the gas-liquid critical point (critical temperature and density) and a change in the width of the phase diagram. In the near-critical region, the latter can be analyzed quantitativly in terms of an effective critical exponent β |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|