  We investigate with Monte Carlo computer simulations the capillary phase
behaviour of model colloid-polymer mixtures confined between a flat wall and a
corrugated wall. The corrugation is modelled via a sine wave as a function of
one of the in-plane coordinates leading to a depletion attraction between
colloids and the corrugated wall that is curvature dependent. We find that for
increased amplitude of corrugation the region of the phase diagram where
capillary condensation occurs becomes larger. We derive a Kelvin equation for
this system and compare its predictions to the simulation results. We find good
agreement between theory and simulation indicating that the primary reason for
the stronger capillary condensation is an increased contact area between the
fluid and the corrugated substrate. On the other hand, the colloid adsorption
curves at colloid gas-liquid coexistence show that the increased area is not
solely responsible for the stronger capillary condensation. Additionally, we
analyse the dimensional crossover from a quasi-2D to a quasi-1D system and find
that the transition is characterised by the appearance of a metastable phase.
