Triple-layered encapsulation through direct droplet impact.

Area of Science:

• Materials Science
• Chemical Engineering
• Nanotechnology

Background:

• Multilayer capsules offer superior protection and multifunctionality compared to single-layered ones.
• Fabricating complex multilayer capsules remains a significant challenge in materials science.
• Existing methods like rapid encapsulation by droplet impact are typically limited to single-shell structures.

Purpose of the Study:

• To explore the feasibility of forming multilayer capsules using a simplified droplet impact approach.
• To investigate the formation dynamics and critical conditions for creating compound droplets with multiple layers.
• To evaluate the protective capabilities and functional adaptability of the fabricated multilayer capsules.

Main Methods:

• Investigated the impact of an aqueous core droplet through a layered liquid pool to form a compound droplet.
• Utilized ultraviolet polymerization to solidify the outer shell of the formed capsule.
• Analyzed capsule formation dynamics and tested protective features through fluorescence monitoring, pH indication, and bacterial viability assays.

Main Results:

• Successfully fabricated defect-free, triple-layered capsules with a solid outer shell.
• Revealed the formation dynamics underlying the multilayer capsule assembly.
• Demonstrated reliable core protection via various assays and showcased functional customization by creating magnetically steerable capsules.

Conclusions:

• The proposed droplet impact and UV polymerization method is effective for fabricating multilayer capsules.
• These capsules provide robust protection for sensitive core materials.
• The approach offers significant flexibility for tailoring capsule functionalities for diverse applications.