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Formation of Two-Dimensional Magnetically Responsive Clusters Using Hematite Particles Self-Assembled via
Jayesh Goswami1, Gokul Nalupurackal1, Muruga Lokesh1
1Department of Physics, Quantum Centres in Diamond and Emergent Materials (QuCenDiEM)-Group, IIT Madras, Chennai 600036, India.
The Journal of Physical Chemistry. B
|September 21, 2023
Summary
Researchers developed a novel method for self-assembling hematite particles using laser-heated upconverting particles (UCPs) to generate convection currents. This technique allows for stable interfacial assembly, enabling magnetic manipulation for interfacial rheology studies.
Area of Science:
- Physics
- Materials Science
- Colloid Science
Background:
- Hematite particles possess high magnetic moments, useful for manipulating physical and biological systems.
- Existing methods for magnetic confinement of hematite particles are complex.
- Laser-based optical confinement of single hematite particles leads to undesirable thermophoretic ejection.
Purpose of the Study:
- To develop a new strategy for inducing self-assembly of hematite particles.
- To overcome limitations of current magnetic and optical confinement techniques.
- To enable magnetic manipulation of assembled hematite structures for interfacial rheology.
Main Methods:
- Utilizing an optically confined and heated upconverting particle (UCP) at an air-water interface.
- Generating convection currents indirectly via the heated UCP to influence hematite particle assembly.
- Investigating the stability of hematite assemblies after laser removal.
- Employing magnetic fields to manipulate the assembled structures.
Main Results:
- Successfully induced self-assembly of hematite particles at the air-water interface.
- Demonstrated that the assembled structures remain stable at the interface even without continuous laser illumination.
- Showcased the ability to move the hematite assemblies using magnetic fields.
- Established the utility of these assemblies for interfacial rheology measurements.
Conclusions:
- Indirect heating via UCPs provides an effective method for hematite particle self-assembly.
- The assembled structures are stable and magnetically controllable.
- This approach offers a promising alternative for interfacial rheology and micromanipulation applications.
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