Microstructure evolution during nano-emulsification by NMR and microscopy
| Autor: | Stefano Guido, Valentina Preziosi, Mick D. Mantle, Einar O. Fridjonsson, Carmine D'Agostino, Abdulaziz Khan |
|---|---|
| Přispěvatelé: | D'Agostino, C., Preziosi, V., Khan, A., Mantle, M., Fridjonsson, E., Guido, S. |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Materials science
Diffusion 02 engineering and technology PFG NMR 010402 general chemistry 01 natural sciences Micelle Biomaterials Colloid and Surface Chemistry Pulmonary surfactant Rheology Nano-emulsions Phase (matter) medicine Lamellar structure Phase inversion emulsification Mineral oil 021001 nanoscience & nanotechnology Microstructure 0104 chemical sciences Nano-emulsion Electronic Optical and Magnetic Materials Surfaces Coatings and Films Chemical engineering 0210 nano-technology CLSM medicine.drug |
| Zdroj: | D'agostino, C, Preziosi, V, Khan, A, Mantle, M, Fridjonsson, E & Guido, S 2019, ' Microstructure evolution during nano-emulsification by NMR and microscopy ', Journal of Colloid and Interface Science, vol. 551, pp. 138-146 . https://doi.org/10.1016/j.jcis.2019.04.098 |
| DOI: | 10.1016/j.jcis.2019.04.098 |
| Popis: | HypothesisMicrostructure evolution in emulsions as a function of composition is of great interest but fundamentals have not yet been fully elucidated. Here, pulsed-field gradient (PFG) NMR diffusion measurements have been combined with confocal laser scanning microscopy (CLSM) to assess evolution of dynamics and microstructure during nano-emulsification.ExperimentsDiffusion coefficients of emulsions made of water, mineral oil and surfactants (Span 20 and Tween 80) were measured as a function of water composition and compared with the morphological features of the emulsions obtained by CLSM.FindingsIn the absence of water, two phases are visible from CLSM, and two diffusion components are observed with PFG NMR, a major fast component attributed to a continuous oil phase containing the more hydrophobic surfactant Span 20 with traces of Tween 80, and a minor slow component attributed to a dispersed phase of the more hydrophilic surfactant Tween 80 with traces of mineral oil and Span 20. At the inversion point (25 wt% water) the two-component diffusion behavior of the oil-rich phase is drastically reversed in terms of populations, with the slow diffusion process becoming dominant. This suggests a significant structuring of the oil-rich phase in the presence of surfactants enhanced by water, which can be explained by the formation of aggregates in the oil phase as reverse micelles or of a lamellar structure, and ties in well with the rheological measurements. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|