Manga, MS, Hunter, TN, Cayre, OJ et al. (6 more authors) (2016) Measurements of sub-micron particle adsorption and particle film elasticity at oil-water interfaces. Langmuir, 32 (17). pp. 4125-4133. ISSN 0743-7463
Abstract
The influence of particle adsorption on liquid/liquid interfacial tension is not well understood, and much previous research has suggested conflicting behaviors. In this paper we investigate the surface activity and adsorption kinetics of charge stabilised and pH-responsive polymer stabilised colloids at oil/water interfaces using two tensiometry techniques; i) pendant drop and ii) microtensiometer. We found, using both techniques, that charge stabilised particles had little or no influence on the (dynamic) interfacial tension; although, dense silica particles affected the 'apparent' measured tension in the pendent drop, due to gravity driven elongation of the droplet profile. Nevertheless, this apparent change additionally allowed the study of adsorption kinetics, which was related qualitatively between particle systems by estimated diffusion coefficients. Significant and real interfacial tension responses were measured using ~53 nm core-shell latex particles with a pH-responsive polymer stabilizer of poly(methylmethacrylate) -b- poly(2-(dimethylamino)ethylmethacrylate) (pMMA-b-pDMAEMA) diblock copolymer. At pH 2, where the polymer is strongly charged, behavior was similar to that of the bare charge-stabilised particles, showing little change in the interfacial tension. At pH 10, where the polymer is discharged and poorly soluble in water, a significant decrease in the measured interfacial tension commensurate with strong adsorption at the oil-water interface was seen, which was similar in magnitude to the surface activity of the free polymer. These results were both confirmed through droplet profile and microtensiometry experiments. Dilational elasticity measurements were also performed by oscillation of the droplet; again, changes in interfacial tension with droplet oscillation were only seen with the responsive particles at pH 10. Frequency sweeps were performed to ascertain the dilational elasticity modulus, with measured values being significantly higher than previously reported for nanoparticle and surfactant systems, and similar in magnitude to protein stabilized droplets.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2016 American Chemical Society. This is an open access article published under a Creative Commons Attribution (CC-BY) License, which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited. |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemical & Process Engineering (Leeds) > Institute for Particle Science and Engineering (Leeds) |
Funding Information: | Funder Grant number EPSRC EP/H030204/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 25 Apr 2016 11:12 |
Last Modified: | 05 Oct 2017 23:36 |
Published Version: | http://dx.doi.org/10.1021/acs.langmuir.5b04586 |
Status: | Published |
Publisher: | American Chemical Society |
Identification Number: | 10.1021/acs.langmuir.5b04586 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:98980 |