Scaling Behavior of Thin Films on Chemically Heterogeneous Walls.

0482992 - ÚCHP 2018 RIV US eng J - Journal Article
Malijevský, Alexandr - Parry, A.O. - Pospíšil, M.
Scaling Behavior of Thin Films on Chemically Heterogeneous Walls.
Physical Review E. Roč. 96, č. 3 (2017), č. článku 032801. ISSN 2470-0045. E-ISSN 2470-0053
R&D Projects: GA ČR(CZ) GA17-25100S
Grant - others:EPSRC(GB) EP/L020564/1
Institutional support: RVO:67985858
Keywords : wetting * scaling * density functional theory
OECD category: Physical chemistry
Impact factor: 2.284, year: 2017

We study the adsorption of a fluid in the grand canonical ensemble occurring at a planar heterogeneous wall which is decorated with a chemical stripe of width L. We suppose that the material of the stripe strongly preferentially adsorbs the liquid in contrast to the outer material which is only partially wet. This competition leads to the nucleation of a droplet of liquid on the stripe, the height hm and shape of which (at bulk two-phase coexistence) has been predicted previously using mesoscopic interfacial Hamiltonian theory. We test these predictions using a microscopic Fundamental Measure Density Functional Theory which incorporates short-ranged fluid-fluid and fully long-rangedwall-fluid interactions. Our model functional accurately describes packing effects not captured by the interfacial Hamiltonian but still we show that there is excellent agreement with the predictions h(m) approximate to L-1/2 and for the scaled circular shape of the drop even for L as small as 50 molecular diameters. For smaller stripes the droplet height is considerably lower than that predicted by the mesoscopic interfacial theory. Phase transitions for droplet configurations occurring on substrates with multiple stripes are also discussed.

Permanent Link: http://hdl.handle.net/11104/0278400