title: Highly CO2/N2-switchable zwitterionic surfactant for pickering emulsions at ambient temperature.
abstract: Cross-linked polymer particles were prepared via surfactant-free emulsion copolymerization of 2-(diethylamino)ethyl methacrylate (DEAEMA) and sodium methacrylate (SMA) using N,N'-methylenebis(acrylamide) (MBA) as a cross-linker. Generated particles are zwitterionic, possessing unique isoelectric points in the pH range of 7.5-8.0, which is readily tunable through CO2/N2 bubbling. The particles were found to be highly responsive to CO2/N2 switching, dissolving in water with CO2 bubbling and precipitating with N2 bubbling at room temperature. Pickering emulsions of n-dodecane were prepared using these particles as the sole emulsifier. These emulsions can be rapidly demulsified with CO2 bubbling, resulting in complete oil/water phase separations. Nitrogen bubbling efficiently re-emulsifies the oil with the aid of homogenization. The rapid emulsification/demulsification using CO2/N2 bubbling at room temperature provides these cross-linked zwitterionic particles with distinct advantages as functional Pickering surfactants.
authors.affiliation: State Key Laboratory of Chemical Engineering, Department of Chemical and Biological Engineering, Zhejiang University , Hangzhou, China 310027.
authors.forename: Pingwei
authors.initials: P
authors.lastname: Liu
authors.forename: Weiqiang
authors.initials: W
authors.lastname: Lu
authors.forename: Wen-Jun
authors.initials: WJ
authors.lastname: Wang
authors.forename: Bo-Geng
authors.initials: BG
authors.lastname: Li
authors.forename: Shiping
authors.initials: S
authors.lastname: Zhu
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry*; D004655:Emulsions; D046529:Microscopy, Electron, Transmission; D009584:Nitrogen / Q000737:chemistry*; D066244:Proton Magnetic Resonance Spectroscopy; D013696:Temperature
chemical_list: D004655:Emulsions; D002245:Carbon Dioxide; D009584:Nitrogen