  A solid substrate, when exposed to a vapour, can interact with it in such a
way that sufficiently close to liquid-vapour coexistence a macroscopically
thick liquid wetting layer is formed on the substrate surface. If such a
wetting transition occurs for a binary fluid mixture in the vicinity of the
critical end point of demixing transitions, critical fluctuations lead to
additional long-ranged interactions (Casimir forces) within the wetting layer,
changing its equilibrium thickness. We demonstrate this effect by Monte-Carlo
simulations of wetting layers of a symmetrical Lennard-Jones binary fluid
mixture near its critical end point. The results suggest that the effect should
also be detectable in corresponding wetting experiments.
