Related Experiment Video
Updated: Jun 8, 2026
13:57
Preparation and Friction Force Microscopy Measurements of Immiscible, Opposing Polymer Brushes
Published on: December 24, 2014
Pickering emulsions stabilized by nanoparticles with thermally responsive grafted polymer brushes
Trishna Saigal1, Hongchen Dong, Krzysztof Matyjaszewski
1Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213-3890, USA.
Langmuir : the ACS Journal of Surfaces and Colloids
|September 14, 2010
Summary
Silica nanoparticles with poly(2-(dimethylamino)ethyl methacrylate) brushes (SiO(2)-PDMAEMA) efficiently stabilize Pickering emulsions. These thermally responsive nanoparticles create stable oil-in-water emulsions, even with poor solvents, and can be reversibly broken by temperature changes.
Area of Science:
- Materials Science
- Colloid and Surface Chemistry
- Polymer Chemistry
Background:
- Pickering emulsions offer an alternative to conventional emulsions stabilized by surfactants.
- Nanoparticle stabilizers provide unique properties for emulsion control.
- Stimuli-responsive polymers enable dynamic control over emulsion stability.
Purpose of the Study:
- To investigate the emulsification capabilities of silica nanoparticles functionalized with poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) brushes.
- To explore the influence of brush grafting density and solution conditions on emulsion stability.
- To demonstrate the creation of thermally responsive Pickering emulsions.
Main Methods:
- Synthesis of SiO(2)-PDMAEMA nanoparticles using atom-transfer radical polymerization (ATRP).
- Stabilization of xylene-in-water and cyclohexane-in-water Pickering emulsions.
- Systematic variation of pH, ionic strength, temperature, and oil solvent quality.
Main Results:
- The lowest grafting density particles (0.077 chains/nm(2)) were the most effective emulsifiers, requiring only 0.05 wt %.
- Stable oil-in-water emulsions were formed with both good (xylene) and poor (cyclohexane) solvents.
- Emulsions remained stable for over 13 months, with up to 83 vol % oil.
- Thermally responsive emulsions were achieved, breaking upon heating above the critical flocculation temperature (CFT).
Conclusions:
- SiO(2)-PDMAEMA nanoparticles are efficient and robust Pickering emulsion stabilizers.
- The efficiency is highest at lower grafting densities.
- The system demonstrates tunable emulsion stability through temperature control, offering potential for novel applications.
