Long-Term Stability of n-Alkane-in-Water Pickering Nanoemulsions... (Thompson et al) 2018 Langmuir.pdf (5.35 MB)
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Long-term stability of n-alkane-in-water pickering nanoemulsions: Effect of aqueous solubility of droplet phase on Ostwald ripening

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journal contribution
posted on 13.09.2019 by Kate L Thompson, Matthew J Derry, Fiona Hatton, Steven P Armes
High-pressure microfluidization is used to prepare a series of oil-in-water Pickering nanoemulsions using sterically-stabilized diblock copolymer nanoparticles as the Pickering emulsifier. The droplet phase comprised either n-octane, n-decane, n-dodecane, or n-tetradecane. This series of oils enabled the effect of aqueous solubility on Ostwald ripening to be studied, which is the primary instability mechanism for such nanoemulsions. Analytical centrifugation (LUMiSizer instrument) was used to evaluate the long-term stability of these Pickering nanoemulsions over time scales of weeks/months. This technique enables convenient quantification of the fraction of growing oil droplets and confirmed that using n-octane (aqueous solubility = 0.66 mg dm-3 at 20 °C) leads to instability even over relatively short time periods. However, using n-tetradecane (aqueous solubility = 0.386 μg dm-3 at 20 °C) leads to significantly improved long-term stability with respect to Ostwald ripening, with all droplets remaining below 1 μm diameter after 6 weeks storage at 20 °C. In the case of n-dodecane, the long-term stability of these new copolymer-stabilized Pickering nanoemulsions is significantly better than the silica-stabilized Pickering nanoemulsions reported in the literature by Persson et al. (Colloids Surf., A, 2014, 459, 48-57). This is attributed to a much greater interfacial yield stress for the former system, as recently described in the literature (see P. J. Betramo et al. Proc. Natl. Acad. Sci. U.S.A., 2017, 114, 10373-10378).

Funding

EPSRC (Fellowship grant EP/R003009/1)

Advanced Investigator ERC grant (PISA 320372)

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Materials

Published in

Langmuir

Volume

34

Issue

31

Pages

9289 - 9297

Publisher

American Chemical Society (ACS)

Version

VoR (Version of Record)

Rights holder

© American Chemical Society

Acceptance date

10/07/2018

Publication date

2018-07-12

Copyright date

2018

ISSN

0743-7463

eISSN

1520-5827

Language

en

Location

United States

Depositor

Dr Fiona Hatton

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