Sugar-responsive Pickering emulsions mediated by switching hydrophobicity in microgels

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:561

Article

Tatry, Marie-Charlotte^1,2  Qiu, Yating¹  Lapeyre, Veronique¹  Garrigue, Patrick¹  Schmitt, Veronique²  Ravaine, Valerie¹ 

[1] Univ Bordeaux, ISM, Bordeaux INP, CNRS,UMR 5255, F-33400 Talence, France

[2] Univ Bordeaux, Ctr Rech Paul Pascal, CNRS, UMR 5031, 115 Ave Dr A Schweitzer, F-33600 Pessac, France

关键词: Responsive polymers;    Microgels;    Pickering emulsions;    Sugar-sensitive materials;    Boronic acids;   

DOI  :  10.1016/j.jcis.2019.11.023

来源: Elsevier

【 摘 要 】

Hypothesis: Pickering emulsions stabilized by soft and responsive microgels can demulsify on demand upon microgel collapse. The concept has been explored with simple model microgels such as poly(Nisopropylacrylamide) (pNIPAM) and their derivatives, but the role of functionalization is largely unexplored. Experiments: Saccharide-responsive phenylboronic-modified microgels are used as Pickering emulsion stabilizers. Emulsion stability and microgel organization at drop surface are studied as a function of saccharide concentration. Better insight into their behavior at interfaces is gained through adsorption kinetics and Langmuir film studies at air-water interface. Findings: The functionalization of water-swollen microgels by phenylboronic functions imparts some hydrophobicity to the structure, at the origin of additional internal cross-links analogous which rigidify the structure compared to non-functionalized microgels, as proved by their slow adsorption kinetics and poor interfacial compressibility. Upon boronate ester formation with diol groups of the saccharide, the hydrophobic character of the phenylboronic acid decreases, increasing the adsorption kinetics and their interfacial compressibility. Emulsions are stable in the presence of saccharide, given the high deformability of the yet-hydrophilic microgels, and mechanically unstable with less deformable particles in low saccharide concentration. The hydrophobic-hydrophilic switch acts as a trigger to tune the microgel stabilizing properties. (C) 2019 Elsevier Inc. All rights reserved.

【 授权许可】

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