Molecular dynamics of drop spreading on a solid surface

We have studied the spreading of liquid drops on a solid surface by molecular-dynamics simulations of Lennard-Jones systems of liquid, vapor, and solid. As the attraction between liquid and solid increases we observe a smooth transition from partial wetting to terraced wetting, with distinct molecular layers spreading with different velocities. In the terraced case the layers are ordered but not solid, with substantial molecular diffusion both within and between layers, and a growth rate that disagrees with experiments with nonvolatile liquids as well as recent calculations.