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Characterizing the spatiotemporal evolution of paramagnetic colloids in time-varying magnetic fields with Minkowski
Elaa Hilou1, Kedar Joshi1, Sibani Lisa Biswal1
1Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX 77005, USA. biswal@rice.edu.
Soft Matter
|August 15, 2020
Summary
External magnetic fields control how superparamagnetic colloids separate into different phases. Researchers studied these dynamics to understand how to tune material properties by adjusting magnetic field strength and particle concentration.
Area of Science:
- Colloid science
- Soft matter physics
- Materials science
Background:
- Phase separation is key to creating novel materials from complex fluids.
- External stimuli like magnetic fields can induce nonequilibrium systems.
- The influence of stimuli on phase transition pathways remains underexplored.
Purpose of the Study:
- To investigate the phase separation dynamics of superparamagnetic colloids under time-varying magnetic fields.
- To understand how external stimuli affect transition pathways and resulting microstructures.
- To explore the control of colloidal phases via magnetic field and particle concentration.
Main Methods:
- Utilized superparamagnetic colloids in time-varying magnetic fields.
- Observed transitions from homogeneous suspension to discrete clusters via a bicontinuous phase.
- Quantified microstructure evolution using Minkowski functionals and analyzed characteristic length scaling.
Main Results:
- Phase separation pathways (voids, bicontinuous, clusters) depend on particle concentration and magnetic field strength.
- Spatiotemporal evolution of microstructure was quantified during nucleation and growth.
- Characteristic length showed power-law scaling with magnetic field strength, particle concentration, and time.
Conclusions:
- External magnetic fields provide a tunable mechanism to control phase separation in colloidal systems.
- Understanding these dynamics allows for precise manipulation of material properties.
- This research opens avenues for designing novel materials with tailored structures.
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