Effect of Criticality on Wetting Layers

We study wetting phenomena in which the wetting layer is (nearly) critical and intrudes between two noncritical phases. Finite-size scaling theory predicts an interaction, identical in range to that due to the van der Waals forces, between the interfaces bounding the wetting layer. This finite-size interaction leads to new wetting phenomena near critical end points, e.g., in ternary mixtures. The interaction amplitude and its possible universality can be observed directly in experiment.