Silicone/vegetable oil Janus emulsion: Topological stability versus interfacial tensions and relative oil volumes

Silicone/vegetable oil Janus emulsion: Topological stability versus interfacial tensions and relative oil volumes

Autor Leonardi, G. R. Autor UNIFESP Google Scholar
Perrechil, F. A. Autor UNIFESP Google Scholar
Silveira, L. P. Autor UNIFESP Google Scholar
Brunca, H. O. Autor UNIFESP Google Scholar
Friberg, S. E. Google Scholar
Instituição Universidade Federal de São Paulo (UNIFESP)
NTNU
Resumo Several aspects were studied of the formation and destabilization in bulk of silicone/vegetable oil, SO/VO, Janus emulsions, stabilized by Tween 80. in the formation of the emulsions, it was unexpectedly found that the dispersions tended to contain both single and flocculated drops irrespective of the emulsification intensity. Microscopy of the emulsions with no cover glass revealed flocculated drops of a large (200-500 mu m) central SO drop with many small VO drops attached. Applying a cover glass did not significantly change the drop size; instead two-oil Janus drops of well-defined contact angle were found. the emulsions showed rapid creaming irrespective of the preparation method, but a few days storage did not significantly change the drop size in the creamed layer, nor was separation of the oils detected. the total interfacial free energy of the Janus drops at equilibrium was compared to the two relevant alternatives; engulfed and separate drops. the Janus drop free energies were found less for all volume ratios of the oils, when the surfactant concentrations in the aqueous phase was sufficient to prevent spreading of VO on SO. Changing the surfactant concentration to bring the interfacial tensions closer to the critical value for spreading gave declining interfacial free energy difference to that of engulfed drops. (C) 2014 Elsevier Inc. All rights reserved.
Assunto Emulsions
Janus drops
Emulsion stability
Interfacial tension
Emulsion free energy
Preparation Janus emulsions
Idioma Inglês
Financiador Ugelstad Laboratory (Norway)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Número do financiamento CNPq: 800075/2014-5
Data 2015-07-01
Publicado em Journal of Colloid and Interface Science. San Diego: Academic Press Inc Elsevier Science, v. 449, p. 31-37, 2015.
ISSN 0021-9797 (Sherpa/Romeo, fator de impacto)
Editor Elsevier B.V.
Extensão 31-37
Fonte http://dx.doi.org/10.1016/j.jcis.2014.09.028
Direito de acesso Acesso aberto Open Access
Tipo Artigo
Web of Science WOS:000353848300005
URI http://repositorio.unifesp.br/handle/11600/39146

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