{"title":"CO2-Switchable High Internal Phase Pickering Emulsions Stabilized by Small-Molecular Surfactants and Hydrophilic Silica Nanoparticles","authors":"Wanqing Zhang, Miao Lv, Jin Shi, Jianzhong Jiang","doi":"10.1021/acssuschemeng.4c09490","DOIUrl":null,"url":null,"abstract":"High internal phase Pickering emulsions (HIPPEs) have received increasing attention recently due to their unique viscosity and rheological characteristics. Nevertheless, their high viscosity might limit their applications in the transportation field. Developing HIPPEs with adjustable stability, controllable viscosity, and easy preparation remains a challenge. Here, we reported an O/W HIPPEs costabilized by a novel CO<sub>2</sub>-switchable nonionic surfactant (NCOEO<sub>3</sub>) and hydrophilic silica nanoparticles with low concentrations, facilitated by the adsorption of NCOEO<sub>3</sub> onto the nanoparticles through hydrogen bonding. Upon increasing the NCOEO<sub>3</sub> concentration to 1 mM, the oil volume fraction of the emulsions can be adjusted to 92%. The HIPPEs demonstrate remarkable CO<sub>2</sub> responsiveness due to the reversible transformation of the surfactant structure between nonionic (NCOEO<sub>3</sub>) and cationic-nonionic (N<sup>+</sup>COEO<sub>3</sub>) forms triggered by CO<sub>2</sub>. This responsiveness enables efficient demulsification at room temperature as well as the recycling and recovery of the surfactant within the aqueous phase. More importantly, the inverted highly viscous HIPPEs could be reversibly converted into flowable low viscous HIPPEs through the CO<sub>2</sub> trigger. This research offers an effective method for preparing intelligent HIPPEs with adjustable properties, such as stability, viscosity, and an aqueous recyclable emulsifier, which can meet various practical application needs.","PeriodicalId":25,"journal":{"name":"ACS Sustainable Chemistry & Engineering","volume":"31 1","pages":""},"PeriodicalIF":7.1000,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACS Sustainable Chemistry & Engineering","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/acssuschemeng.4c09490","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
High internal phase Pickering emulsions (HIPPEs) have received increasing attention recently due to their unique viscosity and rheological characteristics. Nevertheless, their high viscosity might limit their applications in the transportation field. Developing HIPPEs with adjustable stability, controllable viscosity, and easy preparation remains a challenge. Here, we reported an O/W HIPPEs costabilized by a novel CO2-switchable nonionic surfactant (NCOEO3) and hydrophilic silica nanoparticles with low concentrations, facilitated by the adsorption of NCOEO3 onto the nanoparticles through hydrogen bonding. Upon increasing the NCOEO3 concentration to 1 mM, the oil volume fraction of the emulsions can be adjusted to 92%. The HIPPEs demonstrate remarkable CO2 responsiveness due to the reversible transformation of the surfactant structure between nonionic (NCOEO3) and cationic-nonionic (N+COEO3) forms triggered by CO2. This responsiveness enables efficient demulsification at room temperature as well as the recycling and recovery of the surfactant within the aqueous phase. More importantly, the inverted highly viscous HIPPEs could be reversibly converted into flowable low viscous HIPPEs through the CO2 trigger. This research offers an effective method for preparing intelligent HIPPEs with adjustable properties, such as stability, viscosity, and an aqueous recyclable emulsifier, which can meet various practical application needs.
期刊介绍:
ACS Sustainable Chemistry & Engineering is a prestigious weekly peer-reviewed scientific journal published by the American Chemical Society. Dedicated to advancing the principles of green chemistry and green engineering, it covers a wide array of research topics including green chemistry, green engineering, biomass, alternative energy, and life cycle assessment.
The journal welcomes submissions in various formats, including Letters, Articles, Features, and Perspectives (Reviews), that address the challenges of sustainability in the chemical enterprise and contribute to the advancement of sustainable practices. Join us in shaping the future of sustainable chemistry and engineering.