Semipermeable Elastic Microcapsules for Gas Capture and Sensing.

Area of Science:

• Materials Science
• Chemical Engineering
• Nanotechnology

Background:

• Development of advanced materials for gas capture and sensing is crucial for environmental monitoring and industrial applications.
• Microfluidic techniques offer precise control over the fabrication of microscale devices with tailored properties.
• Elastic, semipermeable microcapsules with responsive cores are needed for selective gas interactions.

Purpose of the Study:

• To develop monodispersed microcapsules with tunable elastic polymer shells and pH-sensitive, gas-selective liquid cores.
• To investigate the fabrication of these microcapsules using microfluidics and photopolymerization.
• To evaluate their performance in gas capture, specifically carbon dioxide (CO2), and their morphological stability.

Main Methods:

• Fabrication of microcapsules using glass capillary microfluidics and continuous on-the-fly photopolymerization.
• Utilized specific formulations for inner (K2CO3 solution with m-cresol purple), middle (UV-curable liquid silicon rubber), and outer fluids.
• Developed and validated an analytical model for predicting capsule morphology under osmotic stress; characterized shell properties using TGA, DSC, and FTIR.

Main Results:

• Successfully produced monodispersed microcapsules with tunable size and thickness.
• Achieved efficient CO2 capture capacity of 1.6-2 mmol/g with 30 wt % K2CO3 capsules.
• Demonstrated distinct morphological responses (cavitation vs. buckling) to different rates of internal water removal.

Conclusions:

• The developed microcapsules are effective for gas capture and sensing applications.
• Microfluidics and photopolymerization provide a robust method for creating these advanced microcapsules.
• The study provides insights into capsule stability and gas capture performance, with potential for further optimization.