Sub-micron colloidosomes with tuneable cargo release prepared using epoxy-functional diblock copolymer nanoparticles.

Area of Science:

• Materials Science
• Colloid and Surface Chemistry
• Nanotechnology

Background:

• Pickering emulsions offer a route to fabricating colloidal particles.
• Block copolymer nanoparticles can stabilize emulsions and form capsules.
• Ostwald ripening is a challenge for sub-micron emulsion stability.

Purpose of the Study:

• To create stable sub-micron colloidosomes using epoxy-functional block copolymer nanoparticles.
• To investigate Ostwald ripening stability and tuneable cargo release.
• To develop a method for fabricating robust silica capsules.

Main Methods:

• Synthesis of epoxy-functional diblock copolymer nanoparticles via RAFT polymerization.
• Formation of sub-micron water-in-oil Pickering emulsions using high-pressure microfluidization.
• Cross-linking of emulsions with 3-aminopropyltriethoxysilane (APTES) to form silica colloidosomes.

Main Results:

• Stable sub-micron Pickering emulsions (200-700 nm) were achieved with 0.5 M NaCl, preventing Ostwald ripening.
• Cross-linked colloidosomes exhibited enhanced stability compared to precursor emulsions.
• Silica shell thickness was tunable (11-23 nm), controlling dye release from >99% to ~5%.

Conclusions:

• Epoxy-functional block copolymer nanoparticles enable the formation of stable sub-micron colloidosomes.
• The developed colloidosomes offer tunable permeability for controlled release applications.
• This method provides a robust platform for fabricating advanced silica microcapsules.