Wetting Layers and Dispersion Forces for a Fluid in Contact with a Vertical Wall

When a liquid wets a vertical wall, wetting layers form on the wall high above the liquid-vapor meniscus. These layers are stabilized against gravity by dispersion forces. For SF₆ in contact with fused silica, we find layers between 20 and 40 nm thick in a range of temperatures below critical. Our results support the predictions of Dzyaloshinskii, Lifshitz, and Pitaevskii, in contrast to recent experiments which are much harder to reconcile with theory.