Alkyl Acetamidine Surfactant‐Based Microemulsion and Its CO ₂ ‐Responsive Reversible Switching Properties

This is the authors' abstract. We don't add key points for this paper.

CO 2 ‐responsive switchable microemulsions have attracted significant attention due to their substantial potential in organic synthesis, drug delivery, and nanomaterial preparation. This study presents a microemulsion system composed of N ′‐dodecyl‐ N , N ‐dimethyl acetamidine, 1‐hexanol, brine, and tetradecane. The phase behavior of the microemulsion system was systematically investigated through a salinity scan to access its salinity dependence, while the solubilization ratios were also evaluated. Furthermore, the microstructural characteristics of the microemulsion system were examined using dynamic light scattering, small‐angle X‐ray scattering, and interfacial tension measurements. A transition from Winsor I to Winsor III, and subsequently to Winsor II, was observed in the alkyl acetamidine surfactant‐based microemulsion as salinity increased, with the smallest domain size and most ordered microstructure occurring near the optimal salinity. Notably, the three‐phase microemulsion system demonstrated the ability to reversibly switch between emulsification and demulsification upon CO 2 or N 2 injection, showcasing its dynamic responsiveness. This study enhances the understanding of CO 2 ‐responsive microemulsions and offers potential pathways for sustainable chemical processes.