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Advanced Compositional Analysis of Nanoparticle-polymer Composites Using Direct Fluorescence Imaging
Published on: July 19, 2016
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Investigating Nanoparticle Organization in Polymer Matrices during Reaction-Induced Phase Transitions and Material
Jacob A LaNasa, Anastasia Neuman1, Robert A Riggleman1
1Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
ACS Applied Materials & Interfaces
|August 25, 2021
Summary
Controlling nanoparticle organization in polymer composites is key for material performance. This study reveals a two-step aggregation mechanism for gold nanoparticles during methyl methacrylate polymerization and processing.
Area of Science:
- Materials Science
- Polymer Chemistry
- Nanotechnology
Background:
- Controlling nanoparticle organization in polymer matrices is crucial for material performance.
- Simple mixing often leads to nanoparticle aggregation and detrimental effects.
- In-situ polymerization offers an alternative to physical blending for nanoparticle dispersion.
Purpose of the Study:
- To elucidate the mechanism of nanoparticle aggregation in hybrid materials during polymerization.
- To investigate the influence of polymerization conditions on nanoparticle organization.
- To understand the role of phase separation in nanoparticle dispersion.
Main Methods:
- Synthesis of oleylamine-functionalized gold nanoparticles (AuNP) in methyl methacrylate (MMA) monomer.
- Free radical polymerization of MMA initiated by azobis(isobutyronitrile) (AIBN).
- Characterization using transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS).
- Application of Flory-Huggins mixing theory to explain phase separation.
Main Results:
- Gold nanoparticles initially dispersed in MMA undergo a two-step aggregation process.
- Macrophase separation occurs between poly(methyl methacrylate) (PMMA) and oleylamine during polymerization.
- AuNPs remain dispersed in the oleylamine phase before aggregating during processing (vacuum drying and pressing).
- Final nanoparticle organization is dictated by PMMA-oleylamine mixing thermodynamics.
Conclusions:
- Nanoparticle aggregation in these hybrid materials follows a distinct two-step mechanism linked to polymerization and processing.
- Reaction-induced phase transitions play a critical role in controlling nanoparticle organization.
- Understanding this mechanism allows for tailored nanoparticle dispersion in polymer matrices.
Keywords:
in situ polymerizationmaterial processingnanoparticle dispersionpolymer/inorganic nanoparticle hybrid materialsthermodynamics of mixingMore Related Videos
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