Strong Microcapsules with Permeable Porous Shells Made through Phase Separation in Double Emulsions

Area of Science:

• Materials Science
• Chemical Engineering
• Nanotechnology

Background:

• Microcapsules are vital for controlled chemical release and uptake in various industries.
• Achieving both high mechanical strength and high shell permeability in microcapsules remains a significant challenge.

Purpose of the Study:

• To develop a novel processing route for creating mechanically robust microcapsules with controlled porosity and permeability.
• To investigate the influence of diluents on microcapsule shell structure and properties.

Main Methods:

• Utilizing water-oil-water double emulsions templated in microfluidic devices.
• Incorporating inert diluents (undecanol, butanol) into the oil phase to generate shell porosity via phase separation during polymerization.
• Analyzing the effect of diluent amount and type on shell morphology and mechanical properties.

Main Results:

• Successfully produced mechanically robust microcapsules with a porous shell structure.
• Demonstrated control over shell porosity and permeability by varying the type and amount of inert diluent.
• Established a correlation between diluent properties, phase separation mechanisms, and resulting shell architecture.
• Showcased on-demand release of small molecules triggered by pH changes.

Conclusions:

• A simple and effective method for fabricating high-performance microcapsules has been established.
• The developed microcapsules offer a promising platform for controlled release applications in diverse industrial fields.
• The ability to tune mechanical strength and permeability through diluent selection provides significant design flexibility.