Ettelaie, R orcid.org/0000-0002-6970-4650 and Lishchuk, SV (2015) Detachment force of particles from fluid droplets. Soft Matter, 11 (21). pp. 4251-4265. ISSN 1744-683X
Abstract
We calculate the deformation of a spherical droplet, resulting from the application of a pair of opposite forces to particles located diametrically opposite at the two ends of the droplet. The free-energy analysis is used to calculate the force--distance curves for the generated restoring forces, arising from the displacement of the particles relative to each other. While the logarithmic dependence of the "de Gennes-Hooke" constant on the particle to droplet size ratio, ν, is rather well known in the limit of very small ν, we find that for more realistic particle to droplet size ratios, i.e. ν=0.001 to 0.01, the additional constant terms of O(1) constitute a significant correction to previously reported results. We derive the restoring force constant to be 2πγ[0.5-ln(ν/2)]-1, in perfect agreement with the exact semi-numerical analysis of the same problem. The deviation from the linear force–displacement behaviour, occurring close to the point of detachment, is also investigated. A study of the energy dissipated shows it to be an increasingly dominant component of the work done during the detachment of the particles, as ν decreases. This indicates the existence of a significantly higher energy barrier to desorption of very small particles, compared to the one suggested by their adsorption energy alone. The influence of the line tension on the detachment force is also considered. It is shown that where line tension is important, the contact angle is no longer a constant but instead alters with the displacement of the particles from their equilibrium positions.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2015, Royal Chemistry Society. This is an author produced version of a paper accepted for publication in Soft Matter. Uploaded in accordance with the publisher's self-archiving policy. |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Food Science and Nutrition (Leeds) > FSN Colloids and Food Processing (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 16 Apr 2015 12:58 |
Last Modified: | 26 Oct 2020 14:21 |
Published Version: | http://dx.doi.org/10.1039/C5SM00540J |
Status: | Published |
Publisher: | Royal Society of Chemistry |
Identification Number: | 10.1039/C5SM00540J |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:85102 |