title: Colloids and polymers in random colloidal matrices: demixing under good-solvent conditions.
abstract: 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 differs 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.
authors.affiliation: CNR, Istituto dei Sistemi Complessi (Area della Ricerca di Roma Tor Vergata) Via del Fosso del Cavaliere 100, I-00133 Roma, Italy. annunziata@thphy.uni-duesseldorf.de
authors.forename: Mario Alberto
authors.initials: MA
authors.lastname: Annunziata
authors.forename: Andrea
authors.initials: A
authors.lastname: Pelissetto
mesh_terms: D001703:Biophysics / Q000379:methods*; D003102:Colloids / Q000737:chemistry*; D003198:Computer Simulation; D005740:Gases; D008956:Models, Chemical; D015233:Models, Statistical; D008962:Models, Theoretical; D008968:Molecular Conformation; D011108:Polymers / Q000737:chemistry*; D016062:Porosity; D012997:Solvents / Q000737:chemistry*
chemical_list: D003102:Colloids; D005740:Gases; D011108:Polymers; D012997:Solvents