Highly CO2/N2-switchable zwitterionic surfactant for pickering emulsions at ambient temperature

Area of Science:

• Polymer Chemistry
• Materials Science
• Surface Chemistry

Background:

• Zwitterionic polymers offer unique properties for advanced material applications.
• Stimuli-responsive materials are crucial for developing smart separation technologies.
• Pickering emulsions, stabilized by solid particles, present an alternative to conventional surfactants.

Purpose of the Study:

• To synthesize and characterize novel cross-linked zwitterionic polymer particles.
• To investigate the CO2/N2 responsiveness of these particles in aqueous solutions.
• To evaluate the performance of these particles as Pickering surfactants for emulsion stabilization and demulsification.

Main Methods:

• Surfactant-free emulsion copolymerization of 2-(diethylamino)ethyl methacrylate (DEAEMA) and sodium methacrylate (SMA) with N,N'-methylenebis(acrylamide) (MBA) cross-linker.
• Tuning of isoelectric points (pI) via CO2/N2 bubbling.
• Preparation and characterization of n-dodecane Pickering emulsions.
• Assessment of emulsification/demulsification triggered by CO2/N2 bubbling at room temperature.

Main Results:

• Cross-linked zwitterionic polymer particles with tunable pI (7.5-8.0) were successfully synthesized.
• Particles exhibited significant CO2/N2 responsiveness, dissolving and precipitating accordingly.
• Effective stabilization of n-dodecane Pickering emulsions was achieved using these particles.
• Rapid and reversible emulsification/demulsification was demonstrated upon CO2/N2 switching.

Conclusions:

• The synthesized cross-linked zwitterionic polymer particles are highly responsive to CO2/N2 stimuli.
• These particles demonstrate significant potential as functional Pickering surfactants for tunable emulsion systems.
• The CO2/N2-triggered emulsification/demulsification offers a novel approach for efficient oil-water separation.