  Using the 2D Ising model we study the generic properties of nucleation in
hydrophobic nanopores. To explore the pathways to nucleation of a spin-up phase
from a metastable spin-down phase we perform umbrella sampling and transition
path sampling simulations. We find that for narrow pores the nucleation occurs
on the surface outside the pore. For wide pores the nucleation starts in the
pore, and continues outside the filled pore. Intriguingly, we observe a pore
emptying transition for a range of intermediate pore widths: a pre-critical
nucleus fills the pore, continues to expand outside of the filled pore, but
then suddenly gets expelled from the pore before reaching its critical size.
