Preparation of a magnetocaloric dual-response SiO2-based green nano-emulsifier by an SET-LRP method and evaluation of its properties. (19th January 2023)

• Record Type: Journal Article
• Authors: Lv, Man; Wang, Ling; Huang, Rui; Sun, Yubo; Liu, Xiangbin; Zhou, Wanfu; Wang, Jun
• Is Part Of: European polymer journal. Volume 183(2023)
• Publication Date: 2023-01-19
• Subjects: Single-electron-transfer living radical polymerization -- Magnetocaloric response -- Poly-N-isopropylacrylamide -- Pickering emulsion; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; Polymerization; Polymers; Periodicals; Electronic journals; 547.705
• DOI: 10.1016/j.eurpolymj.2022.111697
• Languages: English
• ISSNs: 0014-3057

Abstract

Graphical abstract: In this study, A green nano-emulsifier (Fe3 O4 @SiO2 @PNIPAM) showing magnetic and thermal responsiveness have been successfully prepared by single-electron-transfer living radical polymerization (SET-LRP). Fe3 O4 @SiO2 @PNIPAM can be easily separated by external magnets, the grafting of PNIPAM increases the heat recovery efficiency of nanoparticles, which is convenient for recycling. The Pickering emulsion prepared by Fe3 O4 @SiO2 @PNIPAM could convert arbitrarily in emulsified state and demulsified state at the external temperature and magnetic field. Highlights: An intelligent green nano-emulsifier was prepared by single-electron-transfer living radical polymerization (SET-LRP). By adjusting the external temperature and magnetic field, Pickering emulsions can be converted between emulsified state and demulsified state. Above LCST, grafting of PNIPAM improves the thermal separation recovery efficiency of nanoparticles. Abstract: In recent years, intelligent nano-emulsifiers have received extensive attention in various fields. In this study, core–shell–shell nanoparticles (Fe3 O4 @SiO2 @PNIPAM) showing magnetic and thermal responsiveness have been successfully prepared as a green nano-emulsifier by single-electron-transfer living radical polymerization (SET-LRP). The emulsifying properties of Fe3 O4 @SiO2 @PNIPAM with different PNIPAM contents in toluene/water systems and the magnetic and thermal responsiveness of Pickering emulsions have been mainly investigated. The research shows that when the content of PNIPAM is higher, Fe3 O4 @SiO2 @PNIPAM has the strongest emulsifying power and the Pickering emulsion is the most stable. After applying a magnet field outside the emulsion, Fe3 O4 @SiO2 @PNIPAM nanoparticles can be separated rapidly, which leads to emulsion demulsification. When the temperature is above the low critical solution temperature (LCST), the PNIPAM chain shrinks and the Pickering emulsion is demulsified. When the temperature returns below the LCST, the emulsion is emulsified again, and a stable emulsion can still be formed. Therefore, the Pickering emulsion made by Fe3 O4 @SiO2 @PNIPAM as an intelligent and efficient green nano-emulsifier can be converted between emulsified state and demulsified state by the control of magnetic field and temperature. These provide a wide range of ideas for Pickering emulsion recycling, industrial oil-containing wastewater separation and enhanced oil recovery.