The spreading behavior of spherical and cylindrical water droplets between 30Å and 100Å in radius on a sapphire surface is investigated using all-atom molecular dynamics simulations for durations on the order of tens of nanoseconds. A monolayer film develops rapidly and wets the surface, while the bulk of the droplet spreads on top of the monolayer, maintaining the shape of a spherical cap. Unlike previous simulations in the literature, the bulk radius is found to increase to a maximum value and receed as the monolayer continues to expand. Simple time and droplet size dependence is observed for monolayer radius and contact angle, and a mathematical model for the spreading dynamics is developed to predict droplet height and bulk radius over time. The model predictions match the simulation data reasonably well, although more work remains in understanding the distinct temporal regimes in the wetting process which this work does not consider
