Pickering Emulsions Stabilized by Diblock Copolymer Worms Prepared via Reversible Addition-Fragmentation Chain Transfer Aqueous Dispersion Polymerization: How Does the Stimulus Sensitivity Affect the Rate of Demulsification?

Yong Gao; Zhe Xiang; Xi Zhao; Guoxiang Wang; Chenze Qi

doi:10.1021/acs.langmuir.1c01609

Pickering Emulsions Stabilized by Diblock Copolymer Worms Prepared via Reversible Addition-Fragmentation Chain Transfer Aqueous Dispersion Polymerization: How Does the Stimulus Sensitivity Affect the Rate of Demulsification?

Langmuir. 2021 Oct 12;37(40):11695-11706. doi: 10.1021/acs.langmuir.1c01609. Epub 2021 Sep 27.

Authors

Yong Gao^{1

2}, Zhe Xiang², Xi Zhao^{1

3}, Guoxiang Wang³, Chenze Qi¹

Affiliations

¹ Key Laboratory of Alternative Technologies for Fine Chemicals Process of Zhejiang Province, College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, Zhejiang 312000, China.
² College of Chemistry and Key Lab of Environment-Friendly Chemistry and Application in Ministry of Education; Key Laboratory of Polymeric Materials & Application Technology of Hunan Province, Key Laboratory of Advanced Functional Polymeric Materials of College of Hunan Province, Xiangtan University, Xiangtan, Hunan Province 411105, China.
³ College of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang, Hunan Province 414006, China.

PMID: 34579524
DOI: 10.1021/acs.langmuir.1c01609

Abstract

Responsive Pickering emulsions exhibit promising application in industry owing to the integration of the high storage stability with on-demand demulsification. In this study, stimuli-responsive Pickering emulsions stabilized by poly[oligo(ethylene glycol) methyl ether methacrylate]₁₅-b-poly(diacetone acrylamide)₁₂₀ (E₁₅D₁₂₀) worms were indicated, in which E₁₅D₁₂₀ worms were prepared via reversible addition-fragmentation chain transfer-based aqueous dispersion polymerization using thermo-sensitive POEGMA₁₅ as both the stabilizer block and macro-chain transfer agent. The factors influencing the morphologies of copolymers during polymerization-induced self assembly have been investigated. A series of different morphological polymer nanoparticles including spheres, worms, and vesicles could be produced through rational synthesis. E₁₅D₁₂₀ worms demonstrated excellent emulsifying performances and could be used as emulsifiers to form n-dodecane-in-water Pickering emulsions at a low content. The formed n-dodecane-in-water Pickering emulsions revealed a slow demulsification at pH 10 or 70 °C or pH 10/70 °C combinations, and several hours were needed for the demulsification of Pickering emulsions. However, n-dodecane-in-water Pickering emulsions displayed a rapid demulsification (∼10 min) at an elevated temperature, such as 90 °C. The different demulsification rates were attributed to different sensitivities of E₁₅D₁₂₀ worms to external stimuli. Pickering emulsions integrating a rapid responsive demulsification with a slow one would be well satisfactory on different occasions.