Non-equilibrium concentration fluctuations in superparamagnetic nanocolloids.
We investigate non-equilibrium concentration fluctuations during the free diffusion of a colloidal suspension against pure water. We investigate Fe2O3superparamagnetic nanocolloids with sizes between 1 and 10 nm by means of a shadowgraph apparatus to determine the mixture mass diffusion coefficient and kinematic viscosity. The experiments were performed in three distinct conditions: Experiment 1 is without any magnetic field; Experiment 2 with a vertical magnetic field; Experiment 3 after turning off the magnetic field. We found no correlation between the kinematic viscosity coefficient and the external magnetic field. Conversely, we found that the mass diffusion coefficient decreases in the presence of the external magnetic field and slowly rebounds after the magnetic field was turned off.
College of Charleston, Department of Physics and Astronomy, Charleston, SC, USA. oprisana@cofc.edu.
Ana
A
Oprisan
College of Charleston, Department of Physics and Astronomy, Charleston, SC, USA.
Ashley
A
Rice
College of Charleston, Department of Physics and Astronomy, Charleston, SC, USA.
Sorinel A
SA
Oprisan
Erlangen Graduate School in Advanced Optical Technologies (SAOT), University of Erlangen-Nuremberg, Erlangen, Germany.
Cédric
C
Giraudet
Laboratoire des Fluides Complexes et leurs Réservoirs - UMR5150, Université de Pau et des Pays de l'Adour, Anglet, France.|Centre Nationale d'Etudes Spatiales (CNES), Paris, France.
Fabrizio
F
Croccolo
D003102:Colloids / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry; D060526:Magnetic Fields; D049329:Nanostructures / Q000737:chemistry*; D014783:Viscosity
D003102:Colloids; D005290:Ferric Compounds; C000499:ferric oxide
Topical Issue: Non-isothermal transport in complex fluids