Bespoke contrast-matched diblock copolymer nanoparticles enable the rational design of highly transparent Pickering double emulsions

Abstract

We report the preparation of highly transparent oil-in-water Pickering emulsions using contrast-matched organic nanoparticles. This is achieved via addition of judicious amounts of either sucrose or glycerol to an aqueous dispersion of poly(glycerol monomethacrylate)56–poly(2,2,2-trifluoroethyl methacrylate)500 [PGMA–PTFEMA] diblock copolymer nanoparticles prior to high shear homogenization with an equal volume of n-dodecane. The resulting Pickering emulsions comprise polydisperse n-dodecane droplets of 20–100 μm diameter and exhibit up to 96% transmittance across the visible spectrum. In contrast, control experiments using non-contrast-matched poly(glycerol monomethacrylate)56–poly(benzyl methacrylate)300 [PGMA56–PBzMA300] diblock copolymer nanoparticles as a Pickering emulsifier only produced conventional highly turbid emulsions. Thus contrast-matching of the two immiscible phases is a necessary but not sufficient condition for the preparation of highly transparent Pickering emulsions: it is essential to use isorefractive nanoparticles in order to minimize light scattering. Furthermore, highly transparent oil-in-water-in-oil Pickering double emulsions can be obtained by homogenizing the contrast-matched oil-in-water Pickering emulsion prepared using the PGMA56–PTFEMA500 nanoparticles with a contrast-matched dispersion of hydrophobic poly(lauryl methacrylate)39–poly(2,2,2-trifluoroethyl methacrylate)800 [PLMA39–PTFEMA800] diblock copolymer nanoparticles in n-dodecane. Finally, we show that an isorefractive oil-in-water Pickering emulsion enables fluorescence spectroscopy to be used to monitor the transport of water-insoluble small molecules (pyrene and benzophenone) between n-dodecane droplets. Such transport is significantly less efficient than that observed for the equivalent isorefractive surfactant-stabilized emulsion. Conventional turbid emulsions do not enable such a comparison to be made because the intense light scattering leads to substantial spectral attenuation.

Publication DOI: https://doi.org/10.1039/c6nr03856e
Divisions: College of Engineering & Physical Sciences
College of Engineering & Physical Sciences > Chemical Engineering & Applied Chemistry
Additional Information: This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
Full Text Link: http://gateway. ... 000381417800020
Related URLs: https://pubs.rs ... 6E#!divAbstract (Publisher URL)
PURE Output Type: Article
Published Date: 2016-07-06
Accepted Date: 2016-07-04
Authors: Rymaruk, Matthew J.
Thompson, Kate L.
Derry, Matthew J. (ORCID Profile 0000-0001-5010-6725)
Warren, Nicholas J.
Ratcliffe, Liam P. D.
Williams, Clive N.
Brown, Steven L.
Armes, Steven P.

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