Smart Emulsions Stabilized by a Multi-headgroup Surfactant Tolerant to High Concentrations of Acids and Salts

Wanqing Zhang; Bernard P Binks; Jianzhong Jiang; Zhenggang Cui

doi:10.1002/anie.202310743

Smart Emulsions Stabilized by a Multi-headgroup Surfactant Tolerant to High Concentrations of Acids and Salts

Angew Chem Int Ed Engl. 2023 Oct 16;62(42):e202310743. doi: 10.1002/anie.202310743. Epub 2023 Aug 31.

Authors

Wanqing Zhang¹, Bernard P Binks², Jianzhong Jiang¹, Zhenggang Cui¹

Affiliations

¹ The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Material Engineering, Jiangnan University, 1800 Lihu Road, 214122, Wuxi, China.
² Department of Chemistry, University of Hull, HU6 7RX, Hull, UK.

PMID: 37599266
DOI: 10.1002/anie.202310743

Abstract

Retaining emulsions stable at high acidity and salinity is still a great challenge. Here, we report a novel multi-headgroup surfactant (C₃ H₇ -NH⁺ (C₁₀ COOH)₂ , di-UAPAc) which can be reversibly transformed among cationic, anionic and zwitterionic forms upon pH variation. Stable oil-in-dispersion (OID) emulsions in strong acidity (pH=2) can be co-stabilized by low concentrations of di-UAPAc and silica nanoparticles. High salinity at pH=2 improves the adsorption of di-UAPAc on silica particles through hydrogen bonding, resulting in the transformation of OID emulsions into Pickering emulsions. Moreover, emulsification/demulsification and interconversion between OID and Pickering emulsions together with control of the viscosity and droplet size can be triggered by pH. The present work provides a new protocol for designing surfactants for various applications in harsh aqueous media, such as strong acidity and high salinity, involved in oil recovery and sewerage treatments.

Keywords: Emulsions; Salt; Stability; Strong Acidity; pH-Responsiveness.

Abstract

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