Inter-droplet force between magnetically polarizable Pickering oil-in-water nanoemulsions stabilized with γ-Al 2 O 3 nanoparticles: Role of electrostatic and electric dipolar interactions.

Autor: Nandy M; Smart Materials Section, Corrosion Science and Technology Division, Materials Characterization Group, Metallurgy and Materials Group, HBNI, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603102, India., Lahiri BB; Smart Materials Section, Corrosion Science and Technology Division, Materials Characterization Group, Metallurgy and Materials Group, HBNI, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603102, India. Electronic address: bblahiri@igcar.gov.in., Philip J; Smart Materials Section, Corrosion Science and Technology Division, Materials Characterization Group, Metallurgy and Materials Group, HBNI, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603102, India.
Jazyk: angličtina
Zdroj: Journal of colloid and interface science [J Colloid Interface Sci] 2022 Feb; Vol. 607 (Pt 2), pp. 1671-1686. Date of Electronic Publication: 2021 Sep 09.
DOI: 10.1016/j.jcis.2021.09.025
Abstrakt: Hypothesis: The presence of nanoparticles at oil-water interface influences the interaction forces between Pickering emulsions. When charged nanoparticles are at the oil-water interface of an electrostatically stabilized emulsion, in addition to the screened Coulombic interaction, electric dipolar force also influences the total inter-droplet force profiles. An in-depth understanding of the effects of such electric dipolar forces is essential for designing colloidally stable Pickering nanoemulsions for various applications.
Experiments: Inter-droplet forces between γ-Al 2 O 3 nanoparticle stabilized oil-in-water nanoemulsion, containing superparamagnetic nanoparticles (magnetically polarizable) in the oil phase, are measured using the magnetic-chaining technique at different pH and salt concentrations. The role of mono-, di- and tri-valent salts on the inter-droplet force profiles are assessed.
Findings: Force measurement studies reveal a lowering of inter-droplet spacing, within the linear chains, for higher salt concentrations due to an increased screening. Strong interfacial attachment of the charged nanoparticles results in the formation of an asymmetric charge cloud leading to an electric dipolar interaction. Incorporating the contributions of electric dipolar and screened Coulombic interactions, the theoretically estimated total repulsive force magnitudes are in good agreement with the experimental data. The obtained results offer better insights into the nature of colloidal force between charged particle stabilized nanoemulsions.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2021 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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