Novel stabilisation of emulsions by soft particles: polyelectrolyte complexes

Bago Rodriguez, Ana Maria; Binks, Bernard P.; Sekine, Tomoko

Abstract

We put forward the concept of a novel particle stabiliser of oil-water emulsions being the polyelectrolyte complex (PEC) formed between oppositely charged water-soluble polymers, in cases where either polymer alone is incapable of stabilising an emulsion. Using poly(4-styrene sulfonate) sodium salt, PSSNa and poly(diallyldimethylammonium chloride), PDADMAC, of low polydispersity and similar molecular mass, we correlate the behaviour of their mixtures in water with that of emulsions after addition of oil. In aqueous mixtures, spherical particles of diameter between 100 and 150 nm are formed through electrostatic interactions between charged polymer chains. Around equal mole fractions of the two polymers, the zeta potential of particles reverses in sign and emulsions of oil-in-water (o/w) for a range of oils can be prepared which are the most stable to coalescence and creaming. Effects of PEC concentration and oil:water ratio have been examined. All emulsions are o/w and stability is achieved by close-packed particle layers at drop interfaces and particle aggregation in the continuous phase. Increasing the salt concentration initially causes destabilisation of the aqueous particle dispersion due to particle aggregation followed by dissolution of particles at high concentrations; the corresponding emulsions change from being stable to completely unstable and are then re-stabilised due to adsorption of uncharged individual polymer molecules.

Citation

Bago Rodriguez, A. M., Binks, B. P., & Sekine, T. (2016). Novel stabilisation of emulsions by soft particles: polyelectrolyte complexes. Faraday Discussions, 191, 255-285. https://doi.org/10.1039/c6fd00011h

• Journal Article Type: Article
• Acceptance Date: Feb 17, 2016
• Online Publication Date: Jul 15, 2016
• Publication Date: Oct 1, 2016
• Deposit Date: Mar 1, 2016
• Publicly Available Date: Jul 15, 2016
• Journal: Faraday discussions
• Print ISSN: 1359-6640
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 191
• Pages: 255-285
• DOI: https://doi.org/10.1039/c6fd00011h
• Keywords: Emulsions
• Public URL: https://hull-repository.worktribe.com/output/411724
• Publisher URL: http://pubs.rsc.org/en/Content/ArticleLanding/2016/FD/C6FD00011H#!divAbstract
• Additional Information: : This document is Similarity Check deposited; CrossRef DOI Link to Discussion:: https://doi.org/10.1039/C6FD90050J; Supplementary Information; : The Royal Society of Chemistry has an exclusive publication licence for this journal; OPEN ACCESS: The accepted version of this article will be made freely available after a 12 month embargo period; : Single-blind; : Received 1 February 2016; Accepted 17 February 2016; Advance Article published 15 July 2016; Version of Record published 6 October 2016
• Contract Date: Mar 1, 2016