Application of statistical mechanics to the wetting of complex liquids

Citation
R. Fondecave et F. Brochard-wyart, Application of statistical mechanics to the wetting of complex liquids, PHYSICA A, 274(1-2), 1999, pp. 19-29
Citations number
18
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics
Journal title
PHYSICA A
ISSN journal
0378-4371 → ACNP
Volume
274
Issue
1-2
Year of publication
1999
Pages
19 - 29
Database
ISI
SICI code
0378-4371(199912)274:1-2<19:AOSMTT>2.0.ZU;2-K
Abstract
We study the wetting laws for binary mixtures with antagonist components: t he solvent wets but the solute does not. Naively, we would expect a wetting transition at a composition phi=phi(w) We measure the contact angle theta( phi) which decreases from theta(1) up to a plateau value theta(L) for phi l ess than or equal to phi(L) In the plateau regime, the solution droplet is in equilibrium with a precursor film of pure solvent. At phi(L), We have a "leak out transition", which results from the frustration of the solvent at tracted by both the polymer and the solid. Because the contact angle is fin ite at all composition, films of solution dewet below a critical thickness e(c)(phi). We observe two regimes of dewetting (i) dry dewetting at composi tion phi > phi(L). The final state after dewetting are multitude of droplet s on a dry solid, (ii) "wet" dewetting for phi < phi(L), where the final dr oplets coexist with a film of pure solvent. All these results can be extend ed to other complex systems, where wetting processes and phase separation a re coupled. (C) 1999 Elsevier Science B.V. All rights reserved.