Inversion of particle-stabilized emulsions of partially miscible liquids by mild drying of modified silica particles

White, Kathryn A.; Schofield, Andrew B.; Wormald, Philip; Tavacoli, Joseph W.; Clegg, Paul S.; Binks, Bernard P.

Abstract

Using a system of modified silica particles and mixtures of water and 2,6-lutidine to form particle-stabilized emulsions, we show that subtle alterations to the hydration of the particle surface can cause major shifts in emulsion structure. We use fluorescence confocal microscopy, solid state nuclear magnetic resonance (NMR) and thermo-gravimetric analysis (TGA) to explore this sensitivity, along with other shifts caused by modifications to the silica surface chemistry. The silica particles are prepared by a variant of the Stöber procedure and are modified by the inclusion of 3-(aminopropyl)triethoxysilane and the dye fluorescein isothiocyanate. Treatment prior to emulsification consists of gently drying the particles under carefully controlled conditions. In mixtures of water and 2,6-lutidine of critical composition, the particles stabilize droplet emulsions and bijels. Decreasing particle hydration yields an inversion of the emulsions from lutidine-in-water (L/W) to water-in-lutidine (W/L), with bijels forming around inversion. So dependent is the emulsion behavior on particle hydration that microscopic differences in drying within a particle sample can cause differences in the wetting behavior of that sample, which helps to stabilize multiple emulsions. The formation of bijels at emulsion inversion is also crucially dependent on the surface modification of the silica. © 2011 Elsevier Inc.

Citation

White, K. A., Schofield, A. B., Wormald, P., Tavacoli, J. W., Clegg, P. S., & Binks, B. P. (2011). Inversion of particle-stabilized emulsions of partially miscible liquids by mild drying of modified silica particles. Journal of colloid and interface science, 359(1), 126-135. https://doi.org/10.1016/j.jcis.2011.03.074

• Journal Article Type: Article
• Acceptance Date: Jul 1, 2011
• Publication Date: Jul 1, 2011
• Journal: JOURNAL OF COLLOID AND INTERFACE SCIENCE
• Print ISSN: 0021-9797
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 359
• Issue: 1
• Pages: 126-135
• DOI: https://doi.org/10.1016/j.jcis.2011.03.074
• Keywords: Pickering emulsion Transitional inversion Bijel Binary fluid Drying Hydration Adsorption Stober silica Colloidal particles 2,6-Dimethylpyridine transitional phase inversion colloidal particles gel surface adsorption mixtures spheres system water
• Public URL: https://hull-repository.worktribe.com/output/396327
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0021979711003729?via%3Dihub