A CO_(2)/N_(2)-Responsive Pickering Emulsion Stabilized by Novel Switchable Surface-Active Alumina Nanoparticles

This article reports the development of a novel switchable Pickering emulsion with rapid CO_(2)/N_(2) respon-siveness,which is stabilized using alumina nanoparticles hydrophobized in situ with a trace amount of a switchable superamphiphile via electrostatic interactions.With the introduction of CO_(2) for 30 s,the Pickering emulsion can be spontaneously demulsified with complete phase separation;the emulsion can then be reconstructed in response to N_(2) purging for 10 min followed by homogenization.Moreover,the stable Pickering emulsion can be stored for more than 60 days at room temperature with-out any visible change.The CO_(2)/N_(2)-responsive behavior of the switchable Pickering emulsion is attribu-ted to the reversible desorption/adsorption of the switchable surfactants on the surfaces of the alumina nanoparticles upon the alternative bubbling of CO_(2)or N_(2).Thanks to the simple fabrication of the surfac-tant and the hydrophobization of the alumina nanoparticles,this research has developed an extremely facile and cost-efficient method for preparing a rapidly CO_(2)/N_(2)-responsive switchable Pickering emul-sion.The dosage of the switchable surfactants has been significantly reduced by nearly 1500 times(from 150 to 0.1 mmol·L^(-1))as compared with the dosage used in previous studies.Moreover,the as-prepared CO_(2)/N_(2)-responsive switchable Pickering emulsion is environmentally friendly,mild,and nontoxic;thus,it holds great potential for practical applications with considerable economic and environmental benefits,such as oil transport,fossil fuel production,environmental gases detection,and the encapsulation and release of active ingredients.

Twofold bioinspiration of TiO_(2)-PDA hybrid fabrics with desirable robustness and remarkable polar/nonpolar liquid separation performance

The fundamental relationship between microstructure,constituent,processing and performances of separating materials is really a vital issue.Traditional preparation methods for separation membranes are complex,time-consuming and easy to be fouled.Also,the durability of conventional coatings on membrane is poor.By combination of bioinspiration from mussel adhesive and fish scales’underwater superoleophobicity,we propose a general route to prepare organic-inorganic hybrid coatings,while no complex apparatus is needed.Specifically,based on the biomimetic adhesion of polydopamine(PDA),we used it as a binder to adhere TiO_(2)nanoparticles and built rough microstructure on fabric.In this way,we obtained TiO_(2)-PDA treated fabric with special wettability.These TiO_(2)-PDA treated samples owned superamphiphilicity in air,underwater superoleophobicity(underwater oil contact angles(OCAs)>150°),underoil superhydrophobicity(underoil water contact angles(WCAs)>150°),excellent multiresistance;and can separate polar/nonpolar liquid mixture effectively.It also owned superaerophobicity underwater(underwater bubble contact angles(BCAs)>150°).The proposed TiO_(2)-PDA coatings are highly expected to be employed for real situation of water pollution remediation,self-cleaning,oil extraction and harsh chemical engineering issues.