Click-active Janus particles

Scalable synthesis and functionalization of clickable Janus particles via seeded emulsion polymerization

Problem:

Amphiphilic Janus particles are biphasic colloids, where each face has distinct chemical properties. Janus particles are useful for stabilizing multiphasic fluid mixtures, such as emulsions. Current methods make Janus particles rely on surface functionalization or phase separation, which have low throughput or require stringent synthesis conditions. Incorporating a secondary monomer is technically challenging for Janus particles and has been previously demonstrated only for seed/core particles.

Solution:

Researchers in the Stebe and Lee Labs have developed a bulk synthesis method for generating click-active polystyrene-poly (propargyl acrylate) Janus particles using phase separation with seeded emulsion polymerization to obtain seed particles. Functionalization is achieved through cross-linking and thiol-alkyne click chemistry.

This technique has been demonstrated with 3 different click reactions, and the morphology has been characterized with scanning electron microscopy. The method can be expanded to seed particles with hydrophobic monomers and a variety of click-active monomers. Particle morphology, composition, and surface charge can all be controlled, achieving chemical flexibility; furthermore, click reactions can occur throughout the bulk of particles or only at the particle surface.

Advantages:

Bulk synthesis from commercially available reagents
Rapid functionalization of a single clickable Janus particle via click-reactions with pendant groups to transform the chemical composition, surface charge, and particle shape in a matter of minutes.
Functionalization without harsh conditions
Tailor particles for particular chemical properties, such as wetting, adhesion, catalysis, and biological recognition
Fabricate stable particles with diverse compositions
Sequential click chemistry can be performed

Applications: