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Hetero-aggregation of oppositely charged nanoparticles
Pooja Bansal1, Abhijit P Deshpande1, Madivala G Basavaraj1
1Polymer Engineering and Colloid Science (PECS) Laboratory, Department of Chemical Engineering, Indian Institute of Technology Madras, Chennai, India.
Journal of Colloid and Interface Science
|January 10, 2017
Summary
This study explores hetero-aggregation of oppositely charged nanoparticles. Different mixing fractions and concentrations reveal distinct aggregate structures and phase behaviors, including particulate gels.
Area of Science:
- Colloid and Surface Science
- Materials Science
- Nanotechnology
Background:
- Hetero-aggregation involves particles with different properties, crucial for applications like porous materials and emulsions.
- Understanding hetero-aggregation is key to controlling the formation of novel structures.
Purpose of the Study:
- To experimentally investigate the hetero-aggregation behavior of similarly sized, oppositely charged nanoparticles.
- To characterize the aggregate size, structure, and flow properties across various mixing fractions and concentrations.
Main Methods:
- Visual observation
- Zeta potential measurements
- Dynamic light scattering
- Scanning electron microscopy
- Rheology measurements
Main Results:
- At low concentrations, four distinct mixture states were observed: sediment with turbid/clear supernatant, turbid sample, and clear dispersion.
- Above ~7.5wt%, mixtures formed particulate gels with turbid supernatant (low mixing fraction), solid-like gels (intermediate), and turbid samples (high mixing fraction).
Conclusions:
- The study elucidates the complex phase behavior of oppositely charged nanoparticle mixtures.
- Findings provide insights into controlling aggregate structures and properties for potential applications.
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