Tuning the bis-hydrophilic balance of microgels: A tool to control the stability of water-in-water emulsions.

Autor: Waldmann L; Bordeaux INP, ISM, UMR 5255 CNRS - Univ. Bordeaux, F-33400 Talence, France; Univ. Bordeaux, CNRS, Bordeaux INP, CBMN UMR 5248, F-33600 Pessac, France., Nguyen DN; IMMM, UMR 6283 CNRS - Le Mans Université, Avenue Olivier Messiaen, 72085 Le Mans cedex 9, France., Arbault S; Univ. Bordeaux, CNRS, Bordeaux INP, CBMN UMR 5248, F-33600 Pessac, France., Nicolai T; IMMM, UMR 6283 CNRS - Le Mans Université, Avenue Olivier Messiaen, 72085 Le Mans cedex 9, France., Benyahia L; IMMM, UMR 6283 CNRS - Le Mans Université, Avenue Olivier Messiaen, 72085 Le Mans cedex 9, France., Ravaine V; Bordeaux INP, ISM, UMR 5255 CNRS - Univ. Bordeaux, F-33400 Talence, France. Electronic address: valerie.ravaine@u-bordeaux.fr.
Jazyk: angličtina
Zdroj: Journal of colloid and interface science [J Colloid Interface Sci] 2024 Jan; Vol. 653 (Pt A), pp. 581-593. Date of Electronic Publication: 2023 Sep 12.
DOI: 10.1016/j.jcis.2023.09.049
Abstrakt: Hypothesis: The stability of purely aqueous emulsions (W/W) formed by mixing incompatible polymers, can be achieved through the Pickering effect of particles adsorption at the interface. However, there is, as yet, no guideline regarding the chemical nature of the particles to predict whether they will stabilize a particular W/W emulsion. Bis-hydrophilic soft microgels, made of copolymerized poly(N-isopropylacrylamide) (pNIPAM) and dextran (Dex), act as very efficient stabilizers for PEO/Dextran emulsions, because the two polymers have an affinity for each polymer phase.
Experiments: The ratio between both components of the microgels is varied in order to modulate the bis-hydrophilic balance, the content of Dex compared to pNIPAM varying from 0 to 60 wt%. The partition between the two aqueous phases and the adsorption of microgels at the W/W interface is measured by confocal microscopy. The stability of emulsions is assessed via turbidity measurements and microstructural investigations under sedimentation or compression.
Findings: The adsorption of particles and their partitioning is found to evolve progressively as a function of bis-hydrophilic balance. At room temperature, the stability of the resulting W/W emulsions also depends on the bis-hydrophilic balance with a maximum of stability for the particles containing 50%wt of Dex, for the Dex-in-PEO emulsions, while the PEO-in-Dex become stable above this value. The thermo-responsiveness of the microgels translates into stability inversion of the emulsions below 50 wt% of Dex in the microgels, whereas above 50 wt%, no emulsion is stable. This work paves the way of a guideline to design efficient and responsive W/W stabilizers.
Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Valerie Ravaine reports financial support was provided by French National Research Agency.
(Copyright © 2023. Published by Elsevier Inc.)
Databáze: MEDLINE
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