Diffusion-Limited Growth of Wetting Layers

In binary liquid mixtures, the growth of wetting layers can be limited by diffusion. At complete wetting, the distance l between the interfaces bounding the layer is shown to grow as l(t)≈A*t^θ for large times t where A* increases near the consolute point. In three dimensions where this growth behavior should be accessible to experiments, θ=1/8 and 1/10 for nonretarded and retarded van der Waals forces, respectively. The interfacial motion resulting from diffusion-limited growth is studied for general interactions, and a planar interface is found to be stable for θ<1/2.