Shear-induced coalescence of oil-in-water Pickering emulsions

Catherine P Whitby; Franziska E Fischer; Daniel Fornasiero; John Ralston

doi:10.1016/j.jcis.2011.05.046

Shear-induced coalescence of oil-in-water Pickering emulsions

J Colloid Interface Sci. 2011 Sep 1;361(1):170-7. doi: 10.1016/j.jcis.2011.05.046. Epub 2011 May 23.

Authors

Catherine P Whitby¹, Franziska E Fischer, Daniel Fornasiero, John Ralston

Affiliation

¹ Ian Wark Research Institute, University of South Australia, Mawson Lakes, South Australia, Australia. catherine.whitby@unisa.edu.au

PMID: 21658702
DOI: 10.1016/j.jcis.2011.05.046

Abstract

This work reports on coalescence in oil-in-water Pickering emulsions subjected to simple shear flow. The emulsions were stabilized by silanized fumed silica particles forming layers a few hundred nanometers thick around drops that are tens of micrometers in size. The drop size and particle concentration in the emulsions were fixed, while the salt concentration was varied to adjust the colloidal interactions between the drops and particles. At rest the oil drops do not coalesce. The susceptibility of the drops to orthokinetic coalescence was found to depend on the extent of particle flocculation in the attached particle layer. The evolution of the drop size with time and shear rate was consistent with phenomenological models used to describe the behavior of emulsions under shear.