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Determining the Effective Density and Stabilizer Layer Thickness of Sterically Stabilized Nanoparticles
Bernice Akpinar1, Lee A Fielding2, Victoria J Cunningham1
1Department of Chemistry, University of Sheffield , Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K.
Macromolecules
|August 2, 2016
Summary
Model diblock copolymer nanoparticles were developed to accurately measure particle density and stabilizer layer thickness. This research improves particle size analysis by accounting for density variations, leading to more precise distribution measurements.
Area of Science:
- Colloid and Surface Chemistry
- Polymer Nanotechnology
- Materials Science
Background:
- Accurate determination of effective particle density and steric stabilizer layer thickness is crucial for nanoparticle characterization.
- Analytical centrifugation techniques (e.g., disk centrifuge photosedimentometry) require precise density values for reliable particle size analysis.
- Steric stabilization effectiveness is fundamentally linked to the properties of the stabilizer layer.
Purpose of the Study:
- To design model sterically stabilized diblock copolymer nanoparticles for developing analytical protocols.
- To accurately determine effective particle density and steric stabilizer layer thickness.
- To improve the precision of particle size analysis using analytical centrifugation.
Main Methods:
- Synthesis of diblock copolymer nanoparticles via polymerization-induced self-assembly (PISA) using RAFT aqueous emulsion polymerization.
- Characterization using transmission electron microscopy (TEM), dynamic light scattering (DLS), and small-angle X-ray scattering (SAXS).
- Calculation of effective particle density based on SAXS-derived radii of gyration and particle size data.
Main Results:
- PGMA-PTFEMA nanoparticles with tunable diameters (20-250 nm) were successfully synthesized.
- Effective particle densities were determined to be between 1.19 and 1.41 g cm⁻³, lower than the PTFEMA solid-state density.
- Recalculation of disk centrifuge photosedimentometry data using accurate density distributions yielded narrower particle size distributions.
Conclusions:
- The developed model nanoparticles facilitate accurate determination of effective particle density and stabilizer layer thickness.
- Accounting for density variations in analytical centrifugation significantly enhances the accuracy of particle size distribution measurements.
- This study provides a robust method for improving nanoparticle characterization, particularly for sterically stabilized systems.
