학술논문
Effect of surfactant concentration on diffusion and microstructure in water-in-oil emulsions studied by low-field benchtop NMR and optical microscopy.
Document Type
Academic Journal
Author
D'Agostino C; Department of Chemical Engineering and Analytical Science, The University of Manchester, The Mill, Sackville Street, Manchester, M13 9PL, UK. carmine.dagostino@manchester.ac.uk.; Dipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali (DICAM), Alma Mater Studiorum - Università di Bologna, Via Terracini, 28, 40131 Bologna, Italy.; Preziosi V; Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università di Napoli Federico II, UdR INSTM, Piazzale Tecchio, 80, 80125, Napoli, Italy. valentina.preziosi@unina.it.; CEINGE, Advanced Biotechnologies, Via Gaetano Salvatore 486, 80145 Napoli, Italy.; Caiazza G; Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università di Napoli Federico II, UdR INSTM, Piazzale Tecchio, 80, 80125, Napoli, Italy. valentina.preziosi@unina.it.; Maiorino MV; Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università di Napoli Federico II, UdR INSTM, Piazzale Tecchio, 80, 80125, Napoli, Italy. valentina.preziosi@unina.it.; Fridjonsson E; Department of Chemical Engineering, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.; Guido S; Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università di Napoli Federico II, UdR INSTM, Piazzale Tecchio, 80, 80125, Napoli, Italy. valentina.preziosi@unina.it.; CEINGE, Advanced Biotechnologies, Via Gaetano Salvatore 486, 80145 Napoli, Italy.
Source
Publisher: Royal Society of Chemistry Country of Publication: England NLM ID: 101295070 Publication Model: Electronic Cited Medium: Internet ISSN: 1744-6848 (Electronic) Linking ISSN: 1744683X NLM ISO Abbreviation: Soft Matter Subsets: PubMed not MEDLINE; MEDLINE
Subject
Language
English
Abstract
Emulsions are ubiquitous in many consumer products, including food, cosmetics and pharmaceuticals. Whilst their macroscopic characterisation is well-established, understanding their microscopic behaviour is very challenging. In our previous work we investigated oil-in-water emulsions by studying the effect of water on structuring and dynamics of such systems. In the present work, we investigate the effect of surfactant concentration on microstructure and diffusion within the water-in-oil emulsion system by using low-field pulsed-field gradient (PFG) NMR studies carried out with a benchtop NMR instrument, in conjunction with optical imaging. The results reveal that at high surfactant concentration the formation of smaller droplets gives rise to a third component in the PFG NMR attenuation plot, which is mostly attributed to restricted diffusion near the droplet boundaries. In addition, structuring effects due to increase in surfactant concentration at the boundaries could also contribute to further slowing down water diffusion at the boundaries. As the surfactant concentration decreases, the average droplet size becomes larger and both restriction and structuring effects at the droplet boundaries become less significant, as suggested by the PFG NMR plot, whereby the presence of a third diffusion component becomes less pronounced.