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China Surfactant Detergent & Cosmetics ›› 2021, Vol. 51 ›› Issue (12): 1186-1191.doi: 10.3969/j.issn.1001-1803.2021.12.004

• Development and application • Previous Articles     Next Articles

Aqueous two-phase Pickering emulsions stabilized by the CLAA@CaCO3 nanoparticles

Hu Jiawen,Fan Ye,Fang Yun(),Wang Hong   

  1. The Key Laboratory of Synthetic and Biological Colloids (Ministry of Education), School of Chemical & Material Engineering, Jiangnan University, Wuxi, Jiangsu 214122, China
  • Received:2021-02-05 Revised:2021-10-23 Online:2021-12-22 Published:2021-12-21
  • Contact: Yun Fang E-mail:yunfang@126.com

Abstract:

Aqueous two-phase system (ATPS) with the advantages of low toxicity, environmental friendliness, and good biocompatibility is often used in the field of separation and purification of biological substances. However, ATPS emulsions (the most common name is water-in-water emulsion) are much less known than oil-in-water or water-in-oil emulsions, since amphiphiles such as surfactants are difficult to adsorb on the water-water interface due to the large thickness of the water-water interface and the corresponding ultralow interfacial tension. Therefore, it is a challenge to develop effective stabilizers for water-in-water emulsions. Colloidal particles are one of the commonly used emulsifiers to stabilize water-in-water emulsion. Herein, CLAA@CaCO3 nanoparticles (NPs) were prepared via adsorbing conjugated linoleic acid admicelle (CLAA) on the surface of CaCO3 nanoparticles followed by stabilizing CLA molecules through self-crosslinking of conjugated double bonds in the CLA molecules by thermal polymerization at 80 ℃, which was confirmed by UV, FT-IR and TG analyses. The phase diagram of the ATPS composed of sodium sulfate and polyethyleneglycol 20000 (PEG 20000) was drawn and the binodal curve and tie lines were established. Subsequently, the CLAA@CaCO3 NPs were used as emulsifiers to stabilize the Pickering emulsions of Na2SO4/PEG 20000 ATPS. The results show that the CLAA@CaCO3 NPs can stabilize the PEG-in-Na2SO4 Pickering emulsions of ATPS when the mass fraction of the CLAA@CaCO3 NPs is 0.1%. Emulsions with different two-phase mass ratios on the same tie line (TL) can remain stable and the droplet size is around 50 μm. Moreover, the PEG-in-Na2SO4 Pickering emulsions with two-phase mass ratios on TL-1, TL-2 and TL-3 respectively have good long-term stability. It is found that the concentrations of the two solutes in the system should be greater than a lowest threshold concentration as indicated between TL-3 and TL-4 in order to obtain the stable Pickering emulsions of ATPS.

Key words: aqueous two-phase system, Pickering emulsion, conjugated linoleic acid, CaCO3 nanoparticle, admicelle

CLC Number: 

  • O648