Pickering emulsions stabilized by carboxylated nanodiamonds over a broad pH range

Huang, Z. ; Jurewicz, I. ; Muñoz, E. ; Garriga, R. (Universidad de Zaragoza) ; Keddie, J. L.

Resumen: Hypothesis: Surfactants in emulsions sometimes do not provide adequate stability against coalescence, whereas Pickering emulsions often offer greater stability. In a search for stabilizers offering biocompatibility, we hypothesized that carboxylated nanodiamonds (ND) would impart stability to Pickering emulsions. Experiments: We successfully prepared Pickering emulsions of sunflower oil in water via two different methods: membrane emulsification and probe sonication. The first method was only possible when the pH of the aqueous ND suspension was ≤ 4. Findings: Pendant-drop tensiometry confirmed that carboxylated ND is adsorbed at the oil/water interface, with a greater decrease in interfacial tension found with increasing ND concentrations in the aqueous phase. The carboxylated ND become more hydrophilic with increasing pH, according to three-phase contact angle analysis, because of deprotonation of the carboxylic acid groups. Membrane emulsification yielded larger (about 30 µm) oil droplets, probe sonication produced smaller (sub-μm) oil droplets. The Pickering emulsions show high stability against mechanical vibration and long-term storage for one year. They remain stable against coalescence across a wide range of pH values. Sonicated emulsions show stability against creaming. In this first-ever systematic study of carboxylated ND-stabilized Pickering emulsions, we demonstrate a promising application in the delivery of β-carotene, as a model active ingredient.

Idioma: Inglés

DOI: 10.1016/j.jcis.2021.10.130

Año: 2022

Publicado en: Journal of Colloid and Interface Science 608, Part. 2 (2022), 2025-2038
ISSN: 0021-9797

Factor impacto JCR: 9.9 (2022)

Categ. JCR: CHEMISTRY, PHYSICAL rank: 29 / 161 = 0.18 (2022) - Q1 - T1

Factor impacto CITESCORE: 15.5 - Chemical Engineering (Q1) - Materials Science (Q1)

Factor impacto SCIMAGO: 1.604 - Biomaterials (Q1) - Surfaces, Coatings and Films (Q1) - Electronic, Optical and Magnetic Materials (Q1) - Colloid and Surface Chemistry (Q1)

Financiación: info:eu-repo/grantAgreement/ES/DGA/E25-20R

Tipo y forma: Article (PostPrint)

Área (Departamento): Área Química Física (Dpto. Química Física)