Breaking Cassie's Law for condensation in a nanopatterned slit
File(s)
Accepted version
Author(s)
Láska, Martin
Parry, Andrew O
Malijevský, Alexandr
Type
Journal Article
Abstract
We study the phase transitions of a fluid confined in a capillary slit made from two adjacent walls, each of which are a periodic composite of stripes of two different materials. For wide slits the capillary condensation occurs at a pressure which is described accurately by a combination of the Kelvin equation and the Cassie law for an averaged contact angle. However, for narrow slits the condensation occurs in two steps involving an intermediate bridging phase, with the corresponding pressures described by two new Kelvin equations. These are characterised by different contact angles due to interfacial pinning, with one larger and one smaller than the Cassie angle. We determine the triple point and predict two types of dispersion force induced Derjaguin-like corrections due to mesoscopic volume reduction and the singular free-energy contribution from nanodroplets and bubbles. We test these predictions using a fully microscopic density functional model which confirms their validity even for molecularly narrow slits. Analogous mesoscopic corrections are also predicted for two-dimensional systems arising from thermally induced interfacial wandering.
Date Issued
2021-03-26
Date Acceptance
2021-03-01
Citation
Physical Review Letters, 2021, 126 (12), pp.1-1
ISSN
0031-9007
Publisher
American Physical Society
Start Page
1
End Page
1
Journal / Book Title
Physical Review Letters
Volume
126
Issue
12
Copyright Statement
© 2021 American Physical Society. This is the Accepted Manuscript version of a published work appearing in Physical Review Letters, https://doi.org/10.1103/PhysRevLett.126.125701
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/33834816
Subjects
General Physics
01 Mathematical Sciences
02 Physical Sciences
09 Engineering
Publication Status
Published
Coverage Spatial
United States
Article Number
125701
Date Publish Online
2021-03-26