Atomic force microscopy for the characterisation of pinning effects of seawater micro-droplets in n-decane on a calcite surface
Author(s)
Type
Journal Article
Abstract
Hypothesis: Roughness is an important parameter in applications where wetting needs to be characterized. Micro-computed tomography is commonly used to characterize wetting in porous media but the main limitation of this approach is the incapacity to identify nanoscale roughness. Atomic force microscopy, AFM, however, has been used to characterize the topography of surfaces down to the molecular scale. Here we investigate the potential of using AFM to characterize wetting behavior at the nanoscale.
Experiments: Droplets of water on cleaved calcite under decane were imaged using quantitative imaging QI atomic force microscopy where a force-distance curve is obtained at every pixel.
Findings: When the AFM tip passed through the water droplet surface, an attraction was observed due to capillary effects, such that the thickness of the water film was estimated and hence the profile of the droplet obtained. This enables parameters such as the contact angle and contact angle distribution to be obtained at a nanometer scale. The contact angles around the 3-phase contact line are found to be quasi-symmetrically distributed between 10–30°. A correlation between the height profile of the surface and contact angle distribution demonstrates a quasi-proportional relationship between roughness on the calcite surface and contact angle.
Experiments: Droplets of water on cleaved calcite under decane were imaged using quantitative imaging QI atomic force microscopy where a force-distance curve is obtained at every pixel.
Findings: When the AFM tip passed through the water droplet surface, an attraction was observed due to capillary effects, such that the thickness of the water film was estimated and hence the profile of the droplet obtained. This enables parameters such as the contact angle and contact angle distribution to be obtained at a nanometer scale. The contact angles around the 3-phase contact line are found to be quasi-symmetrically distributed between 10–30°. A correlation between the height profile of the surface and contact angle distribution demonstrates a quasi-proportional relationship between roughness on the calcite surface and contact angle.
Date Issued
2021-06-15
Date Acceptance
2021-02-15
Citation
Journal of Colloid and Interface Science, 2021, 592 (1), pp.397-404
ISSN
0021-9797
Publisher
Elsevier
Start Page
397
End Page
404
Journal / Book Title
Journal of Colloid and Interface Science
Volume
592
Issue
1
Copyright Statement
© 2021 The Authors. Published by Elsevier Inc.
This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Sponsor
Shell Global Solutions International BV
Shell Global Solutions International BV
Shell Global Solutions International BV
Identifier
https://www.sciencedirect.com/science/article/pii/S0021979721002162
Grant Number
PO no. 4550143956
4550187526
PO no. 4550143956
Subjects
Science & Technology
Physical Sciences
Chemistry, Physical
Chemistry
Atomic force microscopy
Wetting
Contact angle
Atomic force microscopy
Contact angle
Wetting
Chemical Physics
02 Physical Sciences
03 Chemical Sciences
09 Engineering
Publication Status
Published
Date Publish Online
2021-02-22