Magnetic field induced modulated phases in a ferrofluid lutidine silicone oil mixture
| Autor: | Jonas Bugase, Thomas M. Fischer, Johannes Berner |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Ostwald ripening
Ferrofluid Condensed matter physics Chemistry General Chemistry Entropy of mixing Condensed Matter Physics 01 natural sciences Silicone oil 010305 fluids & plasmas Magnetic field Physics::Fluid Dynamics Dipole symbols.namesake chemistry.chemical_compound Phase (matter) 0103 physical sciences symbols Magnetic nanoparticles 010306 general physics |
| Zdroj: | Soft Matter. 12:8521-8527 |
| ISSN: | 1744-6848 1744-683X |
| DOI: | 10.1039/c6sm01713d |
| Popis: | A mixture of an ester based ferrofluid with silicone oil and 2,6-lutidine is exposed to an external magnetic field. We find a region of composition of the ternary mixture, where weak magnetic fields of the order of a few kA m−1 induce a modulated phase with a pattern characterized by equilibrium size droplets of the minority phase immersed into the extended majority phase. While the pattern resembles in many ways the pattern of immiscible magnetic fluids, the dependence of the characteristic parameters of the pattern on the magnetic field are completely different than in immiscible fluids. We theoretically explain the pattern formation as a magnetic field induced polymerization of magnetic particles into magnetic chains that goes along with a reduction of the entropy of mixing. This entropy reduction causes the Ostwald ripening of chains into mesoscopic droplets the size of which is limited by repulsive dipolar interactions between the chains. |
| Databáze: | OpenAIRE |
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