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Non-equilibrium concentration fluctuations in superparamagnetic nanocolloids.
Ana Oprisan1, Ashley Rice2, Sorinel A Oprisan2
1College of Charleston, Department of Physics and Astronomy, Charleston, SC, USA. oprisana@cofc.edu.
The European Physical Journal. E, Soft Matter
|February 10, 2017
Summary
We studied iron oxide nanocolloids and found magnetic fields reduce diffusion. The mass diffusion coefficient decreased with a magnetic field and recovered after it was removed.
Area of Science:
- Colloid and Surface Science
- Nanomaterials Science
- Non-equilibrium Thermodynamics
Background:
- Colloidal suspensions exhibit complex behaviors under external stimuli.
- Understanding diffusion dynamics is crucial for material science and nanotechnology.
- Superparamagnetic iron oxide nanoparticles offer tunable properties.
Purpose of the Study:
- To investigate non-equilibrium concentration fluctuations in colloidal suspensions.
- To determine the effect of an external magnetic field on diffusion coefficients.
- To analyze the recovery of diffusion after magnetic field removal.
Main Methods:
- Utilized a shadowgraph apparatus for precise measurements.
- Employed Fe2O3 superparamagnetic nanocolloids (1-10 nm).
- Conducted experiments under three conditions: no field, vertical magnetic field, and post-field.
Main Results:
- Kinematic viscosity showed no correlation with the magnetic field.
- Mass diffusion coefficient significantly decreased in the presence of a magnetic field.
- A slow rebound of the mass diffusion coefficient was observed after field removal.
Conclusions:
- External magnetic fields influence the mass diffusion of Fe2O3 nanocolloids.
- The observed changes in diffusion are reversible.
- Findings provide insights into controlling nanoparticle transport in magnetic fields.
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