title: Second virial coefficient at the critical point in a fluid of colloidal spheres plus depletants.
abstract: Vliegenthart-Lekkerkerker (VL) criterion B2 = -6vc for second virial coefficient B2 at the critical (colloidal) gas-liquid point is considered for a mixture of spheres with volume vc plus depletants. For the onset of fluid-phase instability, the VL criterion holds for a wide range of shapes of direct attractive forces between hard-core spheres (Vliegenthart, G. A.; Lekkerkerker, H. N. W. J. Chem. Phys. 2000, 112, 5364). In the case of long-ranged attractions imposed indirectly via depletants, it is found that the VL relation fails. Instead, B2/vc at the critical point depends strongly on the sphere/depletant size ratio. By making the hard spheres sticky, we find that B2 moves gradually toward the VL criterion upon increasing the stickiness.
authors.affiliation: Van't Hoff Laboratory for Physical and Colloid Chemistry, Department of Chemistry, Debye Institute, Utrecht University , Padualaan 8, 3584 CH Utrecht, The Netherlands.
authors.forename: Remco
authors.initials: R
authors.lastname: Tuinier
authors.forename: Maartje S
authors.initials: MS
authors.lastname: Feenstra