  We consider a simplified coarse-grained model for colloid-polymer mixtures,
in which polymers are represented as monoatomic molecules interacting by means
of pair potentials. We use it to study polymer-colloid segregation in the
presence of a quenched matrix of colloidal hard spheres. We fix the
polymer-to-colloid size ratio to 0.8 and consider matrices such that the
fraction f of the volume that is not accessible to the colloids due to the
matrix is equal to 40%. As in the Asakura-Oosawa-Vrij (AOV) case, we find that
binodal curves in the polymer and colloid volume-fraction plane have a small
dependence on disorder. As for the position of the critical point, the behavior
is different from that observed in the AOV case: while the critical colloid
volume fraction is essentially the same in the bulk and in the presence of the
matrix, the polymer volume fraction at criticality increases as f increases. At
variance with the AOV case, no capillary colloid condensation or evaporation is
generically observed.
