Synthesis of non-spherical polymer particles using the activated swelling method

Area of Science:

• Polymer Chemistry
• Materials Science
• Nanotechnology

Background:

• Producing non-spherical particles is complex and often lacks reproducibility.
• Janus particles with asymmetric structures are particularly challenging to synthesize.

Purpose of the Study:

• To develop an easy and reproducible method for synthesizing monodisperse, non-spherical polymer particles.
• To control particle shape, including asymmetric Janus structures, using polymerization inhibitors.

Main Methods:

• Activated swelling of monodisperse polystyrene seed particles.
• Controlled free radical polymerization using methyl methacrylate, glycidyl methacrylate, and ethylene glycol dimethacrylate.
• Inhibition of polymerization by 4-methoxyphenol (MEHQ) and O2 to control particle morphology.

Main Results:

• Successfully produced monodisperse non-spherical polymer particles, including dimpled spheres, flattened spheres, and Janus particles.
• Demonstrated that the presence of both MEHQ and O2 is crucial for controlling particle shape.
• Achieved excellent monodispersity and reproducibility across various particle shapes.

Conclusions:

• The activated swelling method combined with controlled polymerization offers a facile route to diverse non-spherical polymer particles.
• This method allows for tunable particle morphology, from spherical to asymmetric Janus structures.
• Incorporation of iron oxide nanocrystals yields superparamagnetic non-spherical particles with enhanced functionality.