title: Depletion effects in a mixture of hard and attractive colloids.
abstract: Monte Carlo simulation and theory were used to study the potential of mean force (PMF) between a pair of big colloidal (solute) particles suspended in a sea of smaller particles (solvent) interacting via Baxter's sticky hard sphere (SHS) potential. Simulation results were obtained by applying a special simulation technique developed for sampling the hard sphere collision force, while the theoretical predictions were calculated from the analytic solution of the Percus-Yevick/Ornstein-Zernike integral equation for spatial correlations in a two-component mixture at vanishing solute concentration. Both theory and simulation revealed oscillations of the solute-solute PMF with a period equal to the diameter of the solvent molecules. Further, the attractive PMF between solute particles in the SHS fluid decays slower than in a hard sphere solvent. Upon increasing the strength of attraction (stickiness) between the molecules of solvent, these oscillations gradually disappear, the PMF becoming long ranged and attractive at all separations.
authors.affiliation: Faculty of Chemistry and Chemical Technology, University of Ljubljana, Askerceva 5, SI-1001 Ljubljana, Slovenia.
authors.forename: A
authors.initials: A
authors.lastname: Lajovic
authors.forename: M
authors.initials: M
authors.lastname: Tomsic
authors.forename: A
authors.initials: A
authors.lastname: Jamnik