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.