Polymerization of electric field-centered double emulsion droplets to create polyacrylate shells

Area of Science:

• Materials Science
• Chemical Engineering
• Physics

Background:

• Hollow and porous particles are crucial in diverse fields like pharmaceuticals, catalysis, and diagnostics.
• Achieving precise control over particle shape, particularly sphericity and concentricity, is vital for advanced applications like high energy density physics.

Purpose of the Study:

• To demonstrate the use of electric field-driven droplet centering for creating highly spherical and concentric polymerizable double emulsion droplets.
• To investigate the subsequent photopolymerization of these centered droplets into uniform polymer shells.

Main Methods:

• Utilized an electric field (∼6 × 10^4 Vrms/m at 20 MHz) to center double emulsion droplets in silicone oil.
• Employed a formulation of silicone oil (inner), tripropylene glycol diacrylate with photoinitiator in N,N-dimethylacetamide (outer), suspended in ambient silicone oil.
• Photopolymerized the centered double emulsion droplets in situ under the influence of the electric field.

Main Results:

• Achieved electric field-driven centering of double emulsion droplets with ≥98% sphericity and ∼98% concentricity.
• The photopolymerization process maintained high degrees of sphericity and concentricity in the resulting polymer shells.
• The synthesized poly(propylene glycol diacrylate) capsules met sphericity requirements for inertial confinement fusion but slightly missed concentricity targets.

Conclusions:

• Electric field-driven centering and polymerization offer a viable method for synthesizing uniform hollow polymer particles.
• This technique shows significant potential for producing polymer shells for high-energy density physics experiments and other specialized applications requiring precise particle morphology.